100
Final Degree Project in Electronics Engineering gLAB upgrade with EGNOS data processing Author: Deimos Ib´ nez Segura Department of Applied Mathematics Universitat Polit` ecnica de Catalunya (UPC) Year: 2016 Directors: Prof. Dr. Jos´ e Miguel Juan Zornoza Dr. Adri` a Rovira Garcia

gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

  • Upload
    letram

  • View
    243

  • Download
    0

Embed Size (px)

Citation preview

Page 1: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Final Degree Project in Electronics Engineering

gLAB upgrade with EGNOS data processing

Author:

Deimos Ibanez Segura

Department of Applied Mathematics

Universitat Politecnica de Catalunya (UPC)

Year: 2016

Directors:

Prof. Dr. Jose Miguel Juan ZornozaDr. Adria Rovira Garcia

Page 2: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 3: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Resum

L’objectiu d’aquest Projecte Final de Carrera es incorporar el processament dedades de SBAS (Satellite-Based Augmentation System o Sistema deAugmentacio Basat en Satel.lits) en el programa gLAB (GNSS-Lab Tool suite)(veure capıtol 2). Aquesta actualitzacio es realitza dins d’un projecte de laESA (European Space Agency o Agencia Espacial Europea) assignat al grupgAGE (Research group of Astronomy and Geomatics o grup de Recercad’Astronomıa i Geodesia Espacial). L’objectiu es proporcionar a la ESA unaeina propia per a processar dades de EGNOS (European GeostationaryNavigation Overlay System o Sistema Europeu Geoestacionari de Cobertura ala Navegacio) -el component europeu de SBAS-. En els requeriments de laESA, es va establir que aquesta havia de ser de codi obert i disenyada ambl’objectiu de ser una eina de referencia per a l’analisi de anomalies i per aqualsevol altre necessitat que pugui sorgir en la ESA (per exemple, lacapacitat de afegir soroll definit per l’usuari a les mesures crues.

Com l’objectiu final d’aquest projecte es implementar la navegacio per satel.lit,amb correccions d’SBAS, s’ha fet una introduccio a GNSS (Global NavigationSatellite System o Sistema Global de Navegacio per Satel.lit) en el capıtol 1 ials sistemes SBAS en el capıtol 3. Amb aixo es preten donar una guia basicaper a la navegacio per satel.lit i els sistemes SBAS, accessible fins i tot per alslectors que no estiguin familiaritzats amb GNSS. A mes, en el capıtol 5 hi hauna gran quantitat d’exemples de com utilitzar l’eina amb la lınia de comandesper a processament massiu.

Page 4: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 5: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Resumen

El objetivo de este Proyecto Final de Carrera es incorporar el procesamiento dedatos de SBAS (Satellite-Based Augmentation System o Sistema deAumentacion Basado en Satelites) en el programa gLAB (GNSS-Lab Toolsuite) (ver capıtulo 2). Esta actualizacion se realiza dentro de un proyecto dela ESA (European Space Agency o Agencia Espacial Europea) asignado algrupo gAGE (Research group of Astronomy and Geomatics o grupo deInvestigacion de Astronomıa y Geodesia Espacial). El objetivo es proporcionara ESA una herramienta propia para procesar datos de EGNOS (EuropeanGeostationary Navigation Overlay System o Sistema Europeo Geoestacionariode Cobertura a la Navegacion) -el componente europeo de SBAS-. En losrequerimientos de ESA, se establecio que esta tenıa que ser de codigo abiertoy disenada con el objetivo de ser una herramienta de referencia para el analisisde anomalıas y para cualquier otra necesidad que pueda surgir en la ESA (porejemplo, la capacidad de anadir ruido definido por el usuario a las medidas encrudo.

Como el objetivo final de este proyecto es implementar la navegacion porsatelite con correcciones de SBAS, se ha hecho una introduccion a GNSS(Global Navigation Satellite System o Sistema Global de Navegacion porSatelite) en el capıtulo 1 y a los sistemas SBAS en el capıtulo 3. Con ello sepretende proveer una guıa basica para la navegacion por satelite y los sistemasSBAS, accesible incluso a lectores no familiarizados con GNSS. Ademas, en elcapıtulo 5 hay una gran cantidad de ejemplos de como utilizar la herramientaen la lınea de comandos para procesamiento masivo.

Page 6: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 7: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Abstract

The objective of this Final Degree Project is to incorporate the dataprocessing from Satellite-Based Augmentation System (SBAS) systems inGNSS-Lab Tool suite (gLAB) software (see chapter 2). This upgrade is donein an European Space Agency (ESA) project awarded to Research group ofAstronomy and Geomatics (gAGE). The objective is to provide ESA apropietary tool for processing European Geostationary Navigation OverlaySystem (EGNOS) -the European component of SBAS- data. In therequirements from ESA, it was established that it had to be open source anddesigned with the aim to be a reference tool for analysing anomalies and forany other specific need should it arise at ESA (e.g. the capability to adduser-defined errors to raw measurements.

As the final purpose of the project is to be able to implement satellite navigationwith SBAS corrections, an introduction to Global Navigation Satellite System(GNSS) is done in chapter 1 and to SBAS systems in chapter 3. Therefore, itis seeked to give a basic background for satellite navigation and SBAS systems,accesible even for readers not familiarized with GNSS. Furthermore, in chapter5 there is large set of examples on how to use the tool in command line forbatch processing.

Page 8: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 9: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Contents

Resum III

Resumen V

Abstract VII

List of Figures XIII

List of Tables XV

Acronyms XVII

1 Introduction 1

2 gLAB description 5

2.1 Main gLAB features . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2 Graphical User Interface (GUI) . . . . . . . . . . . . . . . . . . 7

2.2.1 Positioning tab . . . . . . . . . . . . . . . . . . . . . . 8

2.2.2 Analysis tab . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3 Data Processing Core (DPC) . . . . . . . . . . . . . . . . . . . 10

2.4 gLAB positioning example . . . . . . . . . . . . . . . . . . . . . 11

3 SBAS description 17

Page 10: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

X CONTENTS

4 New Input parameters and output messages in gLAB 27

4.1 Input parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.2 Output messages . . . . . . . . . . . . . . . . . . . . . . . . . 28

5 gLAB usage examples with SBAS 29

5.1 Data gathering for SBAS processing . . . . . . . . . . . . . . . 29

5.2 Command line examples . . . . . . . . . . . . . . . . . . . . . . 31

5.3 SBAS Figures of Merit . . . . . . . . . . . . . . . . . . . . . . 37

6 gLAB applications and future work 41

6.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

6.2 Future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

7 Publications using gLAB 45

8 Conclusion 47

A SBAS Input parameters and output messages 49

A.1 Input parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 49

A.1.1 Help parameters . . . . . . . . . . . . . . . . . . . . . . 49

A.1.2 Input parameters . . . . . . . . . . . . . . . . . . . . . 49

A.1.3 Preprocessing parameters . . . . . . . . . . . . . . . . . 50

A.1.4 Model parameters . . . . . . . . . . . . . . . . . . . . . 51

A.1.5 Filter parameters . . . . . . . . . . . . . . . . . . . . . 54

A.1.6 Output parameters . . . . . . . . . . . . . . . . . . . . 54

A.1.7 Verbose parameters . . . . . . . . . . . . . . . . . . . . 55

A.2 Output messages . . . . . . . . . . . . . . . . . . . . . . . . . 57

A.2.1 USERADDEDERROR message . . . . . . . . . . . . . . 57

A.2.2 SBASCORR message . . . . . . . . . . . . . . . . . . . 58

Page 11: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

CONTENTS XI

A.2.3 SBASVAR message . . . . . . . . . . . . . . . . . . . . 62

A.2.4 SBASIONO message . . . . . . . . . . . . . . . . . . . 64

A.2.5 SBASUNSEL message . . . . . . . . . . . . . . . . . . . 67

A.2.6 SBASOUT message . . . . . . . . . . . . . . . . . . . . 70

Acknowledgments 73

Bibliography 75

Index 79

Page 12: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 13: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

List of Figures

1.1 GPS, GLONASS, Galileo and BeiDou satellites . . . . . . . . . . 2

1.2 GNSS architecture. . . . . . . . . . . . . . . . . . . . . . . . . 2

1.3 GPS, GLONASS, Galileo and BeiDou frequency bands . . . . . 3

2.1 gLAB GUI initial screen . . . . . . . . . . . . . . . . . . . . . . 7

2.2 gLAB GUI initial Positioning tab . . . . . . . . . . . . . . . . . 8

2.3 gLAB GUI initial Analysis tab . . . . . . . . . . . . . . . . . . . 9

2.4 gLAB Input tab example . . . . . . . . . . . . . . . . . . . . . 11

2.5 gLAB Preprocess tab example . . . . . . . . . . . . . . . . . . 12

2.6 gLAB Modelling tab example . . . . . . . . . . . . . . . . . . . 13

2.7 gLAB Filter tab example . . . . . . . . . . . . . . . . . . . . . 13

2.8 gLAB Output tab example . . . . . . . . . . . . . . . . . . . . 14

2.9 gLAB Analysis tab example . . . . . . . . . . . . . . . . . . . . 14

2.10 NEU positioning error . . . . . . . . . . . . . . . . . . . . . . . 15

3.1 SBAS systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.2 SBAS architecture . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.3 Protection levels . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.4 SBAS message example . . . . . . . . . . . . . . . . . . . . . . 24

3.5 SBAS ionosphere grid map . . . . . . . . . . . . . . . . . . . . 25

Page 14: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

XIV LIST OF FIGURES

5.1 GPS receiver in Vigo. . . . . . . . . . . . . . . . . . . . . . . . 30

5.2 Receiver from EGNOS network. . . . . . . . . . . . . . . . . . . 30

5.3 Positioning error with and without SBAS . . . . . . . . . . . . . 38

5.4 Error and protection levels . . . . . . . . . . . . . . . . . . . . 38

5.5 Stanford plots . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.6 Stanford-ESA plots . . . . . . . . . . . . . . . . . . . . . . . . 39

6.1 EGNOS gAGE/UPC monitoring system. . . . . . . . . . . . . . 42

Page 15: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

List of Tables

3.1 Performance requirements . . . . . . . . . . . . . . . . . . . . . 22

A.1 Help parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 49

A.2 Input parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 50

A.3 Preprocessing parameters . . . . . . . . . . . . . . . . . . . . . 51

A.4 Model parameters . . . . . . . . . . . . . . . . . . . . . . . . . 53

A.5 Filter parameters . . . . . . . . . . . . . . . . . . . . . . . . . 54

A.6 Output parameters . . . . . . . . . . . . . . . . . . . . . . . . 55

A.7 Verbose parameters . . . . . . . . . . . . . . . . . . . . . . . . 56

A.8 USERADDEDERROR message . . . . . . . . . . . . . . . . . . 58

A.9 SBASCORR message . . . . . . . . . . . . . . . . . . . . . . . 62

A.10 SBASVAR message . . . . . . . . . . . . . . . . . . . . . . . . 64

A.11 SBASIONO message . . . . . . . . . . . . . . . . . . . . . . . 67

A.12 SBASUNSEL message . . . . . . . . . . . . . . . . . . . . . . . 68

A.13 SBASUNSEL error messages . . . . . . . . . . . . . . . . . . . 70

A.14 SBASOUT message . . . . . . . . . . . . . . . . . . . . . . . . 71

Page 16: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 17: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Acronyms list

AL Alarm Limit

ANTEX ANTenna EXchange format

ARNS Aeronautical Radio Navigation Service

ASCII American Standard Code for Information Interchange

AWGN Additive White Gaussian Noise

BeiDou Big Dipper constellation in Chinese

BNAV Basic research utilities for SBAS NAVigation module

CCN Contract Change Notification

CDDIS Crustal Dynamics Data Information System

CNES Centre National d’Etudes Spatiales

CPU Central Processing Unit

CRC Cyclic Redundancy Check

DAT Data Analysis Tool

DoY Day of Year

DPC Data Processing Core

ECAC European Civil Aviation Conference

EGNOS European Geostationary Navigation Overlay System

EMS EGNOS Message Service

ESA European Space Agency

EUREF European Reference Organisation for Quality Assured BreastScreening and Diagnostic Services

Page 18: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

XVIII Acronyms list

Fast-PPP Fast Precise Point Positioning

FOC Full Operational Capability

GAGAN GPS and GEO Augmented Navigation

gAGE Research group of Astronomy and Geomatics

GAL GALileo Satellite Identifier

Galileo European Global Navigation Satellite System

GBAS Ground-Based Augmentation System

GEO Geostationary Orbit

GIM Global Ionospheric Maps

gLAB GNSS-Lab Tool suite

GLO GLONASS Satellite Identifier

GLONASS GLObal NAvigation Satellite System

GNSS Global Navigation Satellite System

GNU GNU’s Not Unix

GPS Global Positioning System

GSA Galileo Supervisory Authority

GUI Graphical User Interface

HAL Horizontal Alarm Limit

HE Horizontal Error

HMI Hazardous Misleading Information

HPL Horizontal Protection Level

IAC Information and Analysis Centre

IGS International GNSS Service

IGP Ionospheric Grid Point

IOD Issue Of Data

IODE Issue Of Data Ephemerides

IODF Issue Of Data Fast Correction

IODI Issue Of Data Ionospheric

Page 19: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Acronyms list XIX

IODP Issue Of Data PRN mask

IODS Service Issue Of Data

IONEX IONosphere map EXchange format

IPP Ionospheric Pierce Point

MI Misleading Information

MOPS Minimum Operational Performance Standards

MSAS Multi-functional Satellite Augmentation System

MT Message Type

NEU North East Up

NPA Non Precision Approach

PA Precision Approach

Pegasus Prototype EGNOS and GBAS Analysis System Using SAPPHIRE

PL Protection Level

PPP Precise Point Positioning

PRN Pseudo-Random Noise

PRC Pseudo Range Correction

RINEX Receiver INdependent EXchange format

RINEX-B Receiver INdependent EXchange format SBAS binary broadcastmessages

RINEX-H Receiver INdependent EXchange format GEO navigationmessage data

RNSS Radio Navigation Satellite Service

RRC Range Rate Correction

RSS Root Sum Square

SAPPHIRE Satellite and Aircraft Data Base for System Integrity Research

SBAS Satellite-Based Augmentation System

SDCM System for Differential Corrections and Monitoring

SINEX Solution (Software/technique) INdependent EXchange format

SNR Signal to Noise Ratio

Page 20: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

XX Acronyms list

SoL Safety-of-Life

SP3 Standard Product #3

SPP Standard Point Positioning

TGD Total Group Delay

TTA Time-To-Alert

UDRE User Differential Range Error

UDREI User Differential Range Error Indicator

UHF Ultra High Frequency

UIVE User Ionospheric Vertical Error

UPC Technical University of Catalonia

URA User Range Accuracy

URL Universal Resource Locator

USA United States of America

VAL Vertical Alarm Limit

VE Vertical Error

VPL Vertical Protection Level

WAAS Wide Area Augmentation System

WGS-84 World Geodetic System 84

Page 21: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 1

Introduction

A Global Navigation Satellite System (GNSS) system is a constellation ofsatellites orbiting Earth, continuously transmitting signals which enables a userto determine his position in three dimensions (by solving the navigationequations), referenced from the Earth’s centre.

The first GNSS to appear was the Global Positioning System (GPS), initiallyfocused on military use, but in 1983 opened for civilian use (with limitations).Since that date, the number of applications using GNSS for scientific,commercial and daily use has been continuosly increasing, which has meantthat nowadays an important chunk of the global economy is dependent onGNSS (see European GNSS Agency (GSA) (2015)). This fact has meant thatseveral countries have decided to develop their own system.

There are currently four GNSS systems:

• Global Positioning System (GPS): The USA system. The satellitedeployment started at the end of the 1970s, but until July 1995 it wasnot in Full Operational Capability (FOC) (from Sanz et al (2013)).Constellation status can be consulted in USA Navigation Center (2016).

• GLObal NAvigation Satellite System (GLONASS): The Russiansystem. The satellite deploy started in 1982, achieving FOC in December1995, but for only a few years due to lack of funds. In December 2011,it was again in FOC (from Sanz et al (2013)). Constellation status canbe consulted in Information and Analysis Centre (IAC) (2016).

• European Global Navigation Satellite System (Galileo): TheEuropean system. It currently has only 9 fully operational orbitingsatellites. It is scheduled to reach FOC by 2019-2020 (from Sanz et al(2013)). Constellation status can be consulted in European GNSSAgency (GSA) (2016).

Page 22: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

2 Introduction

• Big Dipper constellation in Chinese (BeiDou): The Chinese system.It currently has 18 fully operational orbiting satellites. It is scheduled toreach FOC by 2020 (from Sanz et al (2013)). Constellation status can beconsulted in International GNSS Service (IGS) (2016).

Figure 1.1: GNSS satellites: GPS IIR-M (top left), GLONASS-M (top right),Galileo IOV(bottom left) and BeiDou-M (bottom right) from Sanz et al (2013).

Each GNSS is divided into three segments, as shown in Fig. 1.2:

• Space Segment: Formed by the orbiting satellites.

• Control Segment: Also known as ground segment, composed of acontrol centre for operating the system, monitoring stations distributedaround the world for data collection and ground antennas for uplink datato the satellites.

• User Segment: Any GNSS receiver capable of determining usercoordinates from the GNSS signals. For example, any modernsmartphone.

Ground Antennas

Control Segment Monitoring Stations

Communication Networks

Master Control Station

User Segment

Satellite Satellite Constellation

Space Segment

Figure 1.2: GNSS architecture from Sanz et al (2013).

Page 23: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Introduction 3

Every GNSS transmits signals on two or more different frequencies. There aresome frequencies which are exclusive, others are shared with other GNSSs. Thesignals transmitted by satellites on these frequencies can be classified in threetypes:

• Carrier: Radio frequency sinusoidal signal at a given frequency.

• Ranging code: Sequences of zeros and ones which allow the receiverto determine the travel time of the radio signal from the satellite to thereceiver. They are called Pseudo-Random Noise (PRN) sequences or PRNcodes.

• Navigation data: A binary-coded message providing information on thesatellite ephemeris (pseudo-Keplerian elements or satellite position andvelocity), clock bias parameters, satellite health status and othercomplementary information. This data is updated every two hours.

In Fig. 1.3 is shown the frequency allocation for the GNSS constellations. Anexclusive frequency band allows better signal quality due to the lack ofinterference, but also needs additional electronic to receive it. On the otherhand, shared bandwidth allows to simultaneously receive signals from multipleconstellations with a single receiver, improving navigation accuracy ifadequately combined.

GLONASS Bands GPS Bands Galileo Bands SAR: Galileo Search and Rescue Downlink

L2 E6

SAR

G1

E1

ARNS

RNSS RNSS RNSS

Lower L-Band Upper L-Band

ARNS

RNSS

ARNS: Aeronautical Radio Navigation Service RNSS: Radio Navigation Satellite Service

E5b E5a

B3 L1 B1

L5 B2

Compass Bands

G3 G2

L G E B

Figure 1.3: GNSS frequency bands from Sanz et al (2013).

Page 24: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

4 Introduction

As shown in Fig. 1.3, the are two frequency bands marked as Aeronautical RadioNavigation Service (ARNS), which are exclusive for GNSS signals, thus makingthem suitable for critical operations, such as Safety-of-Life (SoL) or aeronauticaluses, hence the name. The rest of the band frequencies are for Radio NavigationSatellite Service (RNSS), which are shared with radio location services (groundradars).

Furthermore, in Fig. 1.3, it is shown that:

• GPS has 3 frequencies, L1, L2 and L5. L1 has a civil and a military signal,L2 only has a military signal (but in the future will have a civil signal),and L5 has only a civil signal, but is still in deployment phase.

• GLONASS has three frequencies, G1, G2, G3. The three of them haveboth a civil and military signal, but the G3 signals is still in deploymentphase.

• Galileo will have 10 civilian signals in their frequencies E1, E6 and E5 (E5aand E5b signals are modulated in the same frequency E5). It will haveno military signals, but some of them will have restricted access (only forpublic security authorities) or for commercial services.

• BeiDou also has 3 frequencies, B1, B2, B3. B1 and B2 will have publicsignals and restricted signals (commercial or public authorities). B3 onlyhas a restricted signal.

Finally, in order to perform GNSS positioning, the user should use the datagathered from the satellites (ranging code and navigation data) to calculate theposition. A detailed guide on how to perfom this computation is available inSanz et al (2013). In this project, the purpose is to upgrade GNSS-Lab Toolsuite (gLAB) tool, therefore an introduction to this software is given in chapter2 along with a practical example in chapter 2.4.

Page 25: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 2

gLAB description

The GNSS-Lab Tool suite (gLAB) is an advanced interactive educationalmultipurpose package to process and analyze GNSS data. It was initiallydeveloped under the ESA contract number P1081434. The first release of thissoftware package allows full processing capability of GPS data, and partialhandling of Galileo and GLONASS data.

The gLAB software tool performs a precise modelling of the GNSS observables(code and phase) at the centimeter level, allowing GPS standard and precisepoint positioning (SPP, PPP). gLAB also implements full processingcapabilities for GPS data and is prepared to allocate future module updates,such as the expansion to Galileo and GLONASS systems, EGNOS anddifferential processing. It is capable of reading a variety of standard formatssuch as RINEX-3.00, SP3, ANTEX or SINEX files, among others. Moreover,functionality is also included for Galileo and GLONASS, being able to performsome data analysis with real multi-constellation data.

gLAB is flexible, able to run under Linux and Windows operating systems(OS) and it is provided free of charge by the European Space Agency (ESA)to Universities and GNSS professionals. It is programmed in C and Pythonlanguages and is divided into three main software modules:

• The Data Processing Core (DPC)

• The Data Analysis Tool (DAT)

• The Graphical User Interface (GUI)

Page 26: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

6 gLAB description

The DPC implements all the data processing algorithms and can be executedin command line. The DAT provides a plotting tool for the data analysis. TheGUI consists of different graphic panels for user friendly managing of both theDPC and DAT. Both the DPC and DAT modules may be used independently ofthe GUI, by including them in batch files to automatically process GNSS data.

2.1 Main gLAB features

The main gLAB features are:

• High Accuracy Positioning capability: This software tool implements aprecise modelling of the GNSS measurements (code and carrier phase) atthe centimeter level, allowing both standalone GPS positioning and PPP.

• Fully configurable: gLAB is driven by a configuration file, where thedifferent internal parameters are set. These range from input/output anddata processing options such as Kalman filter. This ASCII configurationfile can be generated from the Graphical User Interface (GUI) as well asby any experienced user, with a text editor.

• Easy to use: gLAB includes an intuitive GUI, with tooltips and a lot ofexplanations of the various options to select. Guidelines and several errorand warning messages are also provided, as well as templates and carefullychosen defaults for pre-configured Standard Point Positioning (SPP) andPrecise Point Positioning (PPP) processing modes.

• Access to internal computations: A wide tracking of internalcomputations is provided by gLAB through various output messages.

• Open source: gLAB source code is distributed under the Apache LicenseVersion 2.0. This allows the user to develop both free and commercialGNSS data processing tools using gLAB as a library.

• Automate: Able to be executed in command line and to be included inbatch processing.

• Multi-platform: gLAB can be run in both Linux and Windows. For theformer, any Linux distribution compatible with C compiler and Pythonsupport will work, although Ubuntu is recommended. For the latter, theWindows versions supported are XP, 7, 8 and 10. Furthermore, it runs ona virtual machine with any of these operating systems.

Page 27: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

2.2. Graphical User Interface (GUI) 7

2.2 Graphical User Interface (GUI)

The GUI is an interface between the other two components (DPC and DAT)of gLAB. It allows the user to change parameters, and execute the other twoprograms with proper arguments. The initial screen can be seen in Fig. 2.1,where two main tabs may be found:

• Positioning: Interfaces with the DPC tool, and allows selecting thedifferent processing options.

• Analysis: Interfaces with the DAT, and allows selecting the plottingoptions.

Figure 2.1: gLAB GUI initial screen.

A very important feature of gLAB are the tooltips. When the user hovers themouse over a given option, a small box with information about the item isautomatically displayed. These tooltips help the user to understand what is theeffect of each option on the processing.

Page 28: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

8 gLAB description

2.2.1 Positioning tab

The positioning tab is split into 5 different sections, which correspond to 5different modules inside the DPC:

• INPUT: The “driver” between the input data and the rest of the program.This module implements all the input reading capabilities and stores datain the appropriate internal structures.

• PREPROCESS: This module prepares the data for the next module(MODEL). It checks for cycle-slips, inconsistencies between code andcarrier phase measurements and decimates the data (if required).

• MODEL: This module has all the functions to completely model thereceiver measurements. It implements several kinds of models, which canbe enabled or disabled at will.

• FILTER: This module implements a configurable Kalman filter (fromKalman, Rudolph Emil (1960)), and obtains the estimations of therequired parameters.

• OUTPUT: This module outputs the data obtained from the FILTER.

The GUI also provides two “data processing templates”, shown as buttons inthe lower center part of the interface with labels “SPP Template” and “PPPTemplate” (see Fig. 2.2). Those “templates” automatically configure theappropriate options to carry out the desired data processing strategy.

Figure 2.2: gLAB GUI initial Positioning tab.

Page 29: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

2.2. Graphical User Interface (GUI) 9

2.2.2 Analysis tab

The analysis tab allows configuring all the visualization options for the DAT, asshown in Fig. 2.3. There are two different areas. In the upper part are all thetemplates buttons. In this case, the templates are a set of preconfigured plottingoptions for the Graphic Details section. Clicking on any template button willload all the corresponding options, allowing modifying or plotting them directly.

In the lower part, the user can configure a plot from scratch using the “GlobalGraphic Parameters” section below the templates. The GUI can accommodateup to four plots, (i.e. four different data series in the same graphic) althoughthe DAT program has no plot number limitation when executed independentlyfrom the command line.

Finally, it should be noted that while there are some common data that needsto be uploaded only once per graphic (such as the title and labels), user canfine tune various options of the individual plots, providing full flexibility to theuser.

Figure 2.3: gLAB GUI initial Analysis tab.

Page 30: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

10 gLAB description

2.3 Data Processing Core (DPC)

The DPC is the processing tool of gLAB, and it has been programmed in C. Itsmean features are:

• Easy to use for an advanced user.

• Modularized, in order to incorporate future updates.

• Optimized for CPU and memory usage.

The options of the DPC and GUI are basically the same with some exceptionsthat provide further flexibility. The DPC can be executed with the “-help”argument, which provides detailed information of the possible arguments. It isalso worth mentioning that the DPC can also read the processing options froma configuration file, allowing easy repeatability of results and automatic batchprocessing.

The DPC can work in four different modes:

• Positioning Mode: “Standard” mode, where all the processing is doneand the position solution for a receiver is provided as OUTPUT messages.The minimum parameters required for this mode are an input observationfile and orbit and clock products (broadcast or precise). Using preciseproducts also requires the use of an ANTEX file.

• Show Input Mode: This mode only reads an input RINEX observationfile and prints its measurements. No orbit nor clock products should beprovided (if provided, gLAB will switch to Positioning Mode).

• Product Comparison Mode: This mode reads and compares twodifferent sources of orbit and clock products. In order to use this mode,two different orbit and clock products should be provided. This modeoutputs the SATDIFF, SATSTAT and SATSTATTOT messages.

• Show Product Mode: This mode reads a single source of orbit and clockproducts. In order to use this mode, a single orbit and clock productshould be provided. This mode outputs SATPVT messages with thesatellite coordinates, velocity and clocks.

Page 31: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

2.4. gLAB positioning example 11

2.4 gLAB positioning example

In this section a simple standard positioning example is depicted with gLAB (asit is stated in IS-GPS-200 (2010)). Although it is the least accurate due to theorbits and clocks used, it is the common procedure in mobile and mass-marketdevices due to they only work in single frequency.

The first step is to fill in the “Input tab”. This tab is for the input data for theprogram.

The only required fields are the ’RINEX Observation File’ and ’RINEXNavigation File’. The former has the raw data from the ground receiver whilethe latter has the satellite ephemerides data. In this case, the observation fileused will be “ebre0560.13o” (which is from the station “ebre”, day of yearnumber 056 from year 2013) and the navigation file is “brdc0560.13n” (thebroadcast file compiled by the International GNSS Service (IGS) for the sameday International GNSS Service Products (2014)). The interface should looklike Fig. 2.4:

Figure 2.4: gLAB Input tab configured to do the Standard Point Positioning(SPP).

Page 32: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

12 gLAB description

The next step is to check the “Preprocess tab”. The purpose of this tab is tocheck for data consistency and validity. Some of the checks are:

• Satellite health: Check if the health bits in the RINEX navigationmessage are “0”. If not “0”, it means that a satellite is not sendingvalid data. Then this satellite is discarded further in the processing.

• Cycle slip: When using the phase of the satellite signal (not used inthis example), the measurements must be continuous. When a cycle slipoccurs, measurements are not continuous and the associated carrier-phaseambiguity has to be reset.

This configuration is enough to use the SPP. More information on each optionscan be gathered by hovering over them until its tooltip appears. The interfaceshould look like Fig. 2.5:

Figure 2.5: gLAB Preprocess tab configured to do the SPP.

Page 33: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

2.4. gLAB positioning example 13

In the “Modelling tab”, the different models can be selected to compensate forany errors produced by electronic and propagation effects in the signal, such asthe electronic delays or atmospheric refraction in the troposphere (up to fiftykm height) and ionosphere (between sixty and two thousand km in height).

The default options should be used. The interface should look like Fig. 2.6:

Figure 2.6: gLAB Modelling tab configured to do the SPP.

The “Filter tab” represents the last step in the calculation. After checking forsignal consistency and modelling error sources, a mathematic algorithm, namedKalman filter (see Kalman, Rudolph Emil (1960)), uses all the data to calculatethe current position, using also data from the previous iteration.

The default options should be used, though manipulating the filter optionsrequires advanced knowledge. The interface should look like Fig. 2.7:

Figure 2.7: gLAB Filter tab configured to do the SPP.

Page 34: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

14 gLAB description

Finally, in the “Output tab”, which messages are printed in the output file canbe selected. gLAB can print many values from its internal calculations.

The default options are recommended. At least the OUTPUT messages shouldbe activated. The interface should look like Fig. 2.8:

Figure 2.8: gLAB Output tab configured to do the SPP.

Once the configuration is finished, click on the “Run gLAB” button on thebottom right hand side of the screen to start the computations. Once finished,switch to the ‘Analysis tab’.

In the “Analysis tab”, each of the buttons are for predefined plots. Clicking onthe “NEU positioning error” button will automatically set the configuration forprinting the measurement error in the three axes in North East Up (NEU)coordinates (see appendix B of Sanz et al (2013) for coordinate systemsdescription). The interface should look like Fig. 2.9:

Figure 2.9: gLAB Analysis tab configured to do the NEU positioning error plot.

Page 35: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

2.4. gLAB positioning example 15

Clicking on the “Plot” button in bottom right hand side of the screen will showthe requested plot. It should look like Fig. 2.10:

Figure 2.10: NEU positioning error for 24 hours on the 25th February 2013 forstation “ebre”.

In the plot, for most of the day the North and East error (corresponding to a2D positioning) is ±2 meters, but the Up error (height) is much higher (up to 8meters). This is due to that the satellites in range tend to surround the user (ifseen from user’s position), there are signals from many directions, decreasingthe mean error, except in the Up axis, because the Earth blocks the satellite’ssignals which are at the other side of the planet. Indeed, a user can see severalsatellites around its position in North and East axes (which makes the errors onthese axes slightly compensate each other), but not in the Up axis, because theearth blocks the satellite signals which are at the other side of the planet.

The plot shown in Fig. 2.10 is a typical result from SPP. The peak errors thatappear are linked to several causes, such as ionospheric errors, code multipathor poor geometries (see IS-GPS-200 (2010)).

Page 36: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 37: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 3

SBAS description

Global Navigation Satellite System (GNSS) systems that are in FullOperational Capability (FOC), such as GPS and GLONASS, provide goodresults for simple applications (e.g any app for smartphones). However, forSafety-of-Life (SoL) applications such as civil aviation, standalone GNSSpresents important limitations. These are the following:

• Integrity: The definition from ICAO (2006) is: Integrity is a measure ofthe trust that can be placed in the correctness of the information suppliedby the total system. Integrity includes the ability of a system to providetimely and valid warnings to the user (alerts) when the system must not beused for the intended operation (or phase of flight). It is the probability ofhaving erroneus information. This assures that the information providedcan always be trusted by the navigation system, because there is a qualitycheck of the input data. If the output data may be not safe, the system hasto warn the user (time-to-alert) as soon a possible (less than 10 seconds).For GNSS systems, if a satellite has a malfunction, it can take up to 2hours until the satellite broadcast message is updated with the satellitehealth flag set to don’t use. It is measured as the probability of receivinga false alarm (see table 3.1).

• Availability: The definition from ICAO (2006) is: The availability ofGNSS is characterized by the portion of time the system is to be usedfor navigation during which reliable navigation information is presented tothe crew, autopilot, or other system managing the flight of the aircraft.A system high availability has to be online at least 99.999% of the timeduring one year (that is, it only can be offline slightly more than 5 minuteseach year). During the last decades with GNSSs, the only system withthis availability has been GPS.

Page 38: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

18 SBAS description

• Accuracy: The definition from ICAO (2006) is: GNSS position error isthe difference between the estimated position and the actual position.For an estimated position at a specific location, the probability shouldbe at least 95 per cent that the position error is within the accuracyrequirement. Depending on the application, metre level or centimetrelevel may be required. For meter level, single frequency is enough, butfor centimetre precision, dual frequency is required. The problem withdual frequency is that, currently, signals in L2 frequency are only formilitary use. Nevertheless, nowadays any commercial receiver can trackthe military signals, but the governments, at any moment, might changethe codes of these signals, resulting in all commercial receivers losing trackof these signals. For this reason, military signals cannot be considered forSoL as their availability is not guaranteed. In the near future, when L5signals are fully deployed in GNSSs, these will be incorporated in futureupdates of SBAS.

• Continuity: The definition from ICAO (2006) is: Continuity of serviceof a system is the capability of the system to perform its functionwithout unscheduled interruptions during the intended operation. It isthe probability that the system will keep its performance during theduration of a phase of operation. Lack of continuity means that theoperation has to be aborted (with the risk implied). GNSSs were notdesigned to provide a specific continuity goal, therefore no continuitycan be assured.

Additionally, although it is not a direct SBAS requirement, it is also veryimportant that the system is protected against interferences (eitheraccidentally or intentional). L1 GNSS signals are at an aeroprotectedfrequency, which means that this frequency has exclusive usage, and anyinterference is to be considered a major offence or even a crime, while L2GNSS signals are not at an aeroprotected frequency.

For the reasons mentioned above, the only signal which is suitable to be usedfor SoL services is the C1C signal in L1 frequency in GPS. But using just thissignal for positioning does not meet the integrity and accuracy requirements.The 3D positioning error with this signal is about 3 to 10 meters (see Fig 2.10),and this error can increase depending on the satellite clocks and the level ofionization in the ionosphere (the higher the ionization, the higher are GNSSsignals delayed). The ionosphere model broadcast for GPS is only 6 lines ofcode (but good enough for SPP), so it is vulnerable to days with high activityin the ionosphere.

Page 39: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

SBAS description 19

Thus, to meet SoL requirements, SBAS receiver needs additional datacontaining the following information:

• Corrections: Corrections for signal delays in real time will improve theaccuracy of the positioning.

• Confidence bounds: Confidence bounds provide information on thequality of the data, and also inform which data (satellites) can be usedfor computing the navigation solution.

• Ionosphere model: The ionosphere is an important error source andit is difficult to model. A good ionosphere model is very important forimproving accuracy.

In order for a receiver to get this additional information, there has to be anexternal system which computes these corrections and broadcasts them to theuser. These systems are called augmentation, and for SoL purposes, there arecurrently two types:

• GBAS: Ground-Based Augmentation System. This is for broadcastingcorrections in a local area (forty-three kilometers, from SC-159 (2005)).It is installed in airports, and each airport GBAS system is independentfrom others. This system does not need to provide a ionospheric model,as it can be assumed that the error produced in the airplane measurementis the same as the error measured in the base station at the airport. Thedata is broadcast through Ultra High Frequency (UHF) radio links.

• SBAS: Satellite-Based Augmentation System. This is for broadcastingcorrections in a wide area (continents). The data is broadcast throughgeostationary satellites.

As the aim of this project is to implement SBAS on gLAB, we will focus onlyon SBAS systems. Currently, we have the following SBAS available or indevelopment (as we can see in Fig 3.1):

Page 40: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

20 SBAS description

Figure 3.1: SBAS systems from OXTS (2014).

• WAAS: Wide Area Augmentation System (WAAS) is the first SBASdeveloped and fully operational. It has been developed by the UnitedStates of America (USA) and only provides service in the USA.Corrections are only for GPS constellation. Operational since 2003 (fromNavipedia (2011c)).

• EGNOS: European Geostationary Navigation Overlay System (EGNOS)is the European system. Provides service to all the European Civil AviationConference (ECAC) area (see ECAC (2016)). Corrections are only for GPSconstellation, but in the future it will include Galileo. Operational since2011 (from Navipedia (2011a)).

• MSAS: Multi-functional Satellite Augmentation System (MSAS) is thejapanese system. Provides service only to Japan. Corrections are only forGPS constellation. Operational since 2007 (from Navipedia (2011b)).

• SDCM: System for Differential Corrections and Monitoring (SDCM) isthe Russian system. It is still in development phase, and it will provideservice only in Russia. It is the only system that will provide correctionsfor GPS and GLONASS constellations.

• GAGAN: GPS and GEO Augmented Navigation (GAGAN) is the Indiansystem. It is still in development phase, and it will provide service only inIndia. Corrections are only for GPS constellation.

Page 41: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

SBAS description 21

Each SBAS system have the following architecture (similar to GNSS systems)as we can see in Fig 3.2:

• Ground Segment: Network of GNSS receivers spread throughout theservice area. These receivers provide data to a few master stations, whichcompute the SBAS corrections and send them to the uplink stations,which will send the corrections to the GEO satellites.

• Space Segment: Consists of a set of GEO satellites covering the desiredarea. WAAS and EGNOS have 3 GEO in each SBAS orbit. GEO satellitesbroadcast the corrections to the users.

• User segment: For SoL purposes, it must be a SBAS certified receiver.For other non SoL purposes, any GNSS receiver able to track SBAS signalscan use the SBAS corrections.

Figure 3.2: SBAS architecture from NovAtel (2013).

The performance of SBAS systems is defined with respect to the level of servicethat the system is commited to provide. The most important use for SBAS iscivil aviation, thus performances come from its navigation safety requirements.These vary from each operation mode, which are shown in table 3.1, and themodes are the following:

Page 42: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

22 SBAS description

• PA: Precision Approach mode. Occurs when an aeroplane is approachinga terminal for landing.

• NPA: Precision Approach mode. Occurs when an aeroplane is notapproaching a terminal for landing (i.e. en route over earth or ocean anddeparture in terminals).

OperationNon Precision

Approach (NPA)Precision

Approach (PA)Horizontal Accuracy

(95%)220 m 16 m

Vertical Accuracy(95%)

N/A 20 m

Integrity 1 · 10−7/h 2 · 10−7 per approach

Time-To-Alert (TTA) 10 s 10 s

Continuity 1 · 10−4/h to 1 · 10−8/h 8 · 10−6 in any 15 s

Availability 0.99 to 0.99999 0.99 to 0.99999

Table 3.1: Performance requirements from ICAO (2006).

The integrity requirement in table 3.1 refer to the probability of having erroneousinformation (which is called as Misleading Information (MI)) and the probabilityof not fullfilling the operation performance requirements. In order to define whenthere is an integrity or continuity risk, the following terms are defined:

• Protection Level (PL): Users know the receiver-satellites geometryand can compute confidence bounds on the horizontal and verticalposition errors. These bounds are called Protection Levels (HorizontalProtection Level (HPL) and Vertical Protection Level (VPL)). Theyprovide a measurement of confidence that the true position is within aellipsoid around the computed position (see Fig 3.3).

• Alarm Limit (AL): The threshold for protection levels. When anyprotection level exceeds this threshold, the system is declared asunavailable. There is one threshold for each component, HorizontalAlarm Limit (HAL) and Vertical Alarm Limit (VAL) for horizontal andvertical components.

Page 43: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

SBAS description 23

Figure 3.3: Protection levels from Hernandez-Pajares et al (2002).

According to these definitions, we can set four modes of operation in a SBASsystem (this modes will be later explained in Fig 5.5 in chapter 5.3):

• Normal operation: When the navigation error is below the ProtectionLevel and the Protection Level is under the Alarm Limit.

• Misleading Information (MI): When the navigation error is above theProtection Level.

• Hazardous Misleading Information (HMI): When the navigationerror is above the Protection Level and above the Alarm Limit, but theProtection Level is below the Alarm Limit.

• System unavailable: When the Protection Level is above the AlarmLimit. If the error is above the Protection Level, the SBAS positioningwill also present Misleading Information.

In order to fulfill the above requirements, SBAS systems broadcast binarymessages at a bitrate of 250 bits/s with a standard format (see Fig 3.4).These messages can provide corrections up to 51 satellites (of one or moreGNSS constellations) concurrently. The corrections in these messages can bedivided into three Message Type (MT):

Page 44: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

24 SBAS description

• Fast Corrections: Corrections for satellite clocks and their confidencebounds. Clocks vary very fast, so fast corrections have to be updated every12 seconds and their confidence bounds every 6 seconds (from RTCA-MOPS (2006)). They are broadcast in MT 2, 3, 4, 5, 6 and 24 (first halfmessage of type 24 is for fast corrections, see Fig 3.4).

• Slow Corrections: Corrections for satellite broadcast ephemerides(satellite orbits and other slow varying terms). They need to be updatedevery 5 minutes (from RTCA-MOPS (2006)). They are broadcast in MT9,10,17,24 (last half message of type 24 is for slow corrections, seeFig 3.4), 25, 27 and 28.

• Ionosphere Corrections: Corrections for ionosphere delay. Thecorrection is broadcast using a world map grid (with variable distancebetween points) divided by bands (see Fig 3.5). Each SBAS will onlybroadcast the corrections for the area where it is providing service. Theyneed to be updated every 5 minutes (from RTCA-MOPS (2006)). Theyare broadcast in MT 18 and 26.

Figure 3.4: SBAS message example from RTCA-MOPS (2001).

All of the corrections mentioned above provide not only the correction itself, butalso its error bound (sigma). These error bounds are an important componentof the SBAS messages, by combining the error bounds from all the correctionsprovide the error bound for the satellite measurement, which will be used forcomputing the Protection Level of the user. Therefore, the integrity of SBASnavigation is directly linked to the realism of these error bounds.

Page 45: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

SBAS description 25

The methodology to combine all the fast corrections, slow corrections andionosphere corrections is complex (see appendix A and J of RTCA-MOPS(2006)), as it must take into consideration all the rules for synchronizationbetween messages, the degradation terms (for the case when newer messagesare lost and the available messages propagate in time) and the rules forcomputing the overall error bounds. These rules apply for a large number ofpossible cases, and it is beyond the current scope to explain them in thisdocument (as the number of added lines in gLAB code is nearly sixteenthousand), but if the reader is interested in further details, there is thefollowing article Todd Walter (1999) with practical examples on how tocompute the SBAS corrections.

Figure 3.5: SBAS ionosphere grid map from RTCA-MOPS (2001).

Page 46: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 47: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 4

New Input parameters andoutput messages in gLAB

The version of gLAB has been upgraded with the aim of being a tool notonly for processing SBAS data, but able to be used for tracking down anyanomaly encountered in the SBAS processing. For this purpose, the tool hasmany input parameters so that the processing can be modified in many ways,as well as having output messages with all the internal computations as wellas human readable messages (e.g. the messages explaining why a satellite hasbeen discarded for positioning).

It is also worth mentioning that even though the most time-consuming task wasto program the decoding and processing of SBAS data, designing the tool withso many processing options (which many of them do not follow the MOPS, butare very useful for investigations) also took a large amount of time and effort.

4.1 Input parameters

The new input parameters are divided into the following sections:

• Help parameters: These parameters make gLAB show large helpmessages and then exit without processing.

• Input parameters: These parameters are for selecting the input files tobe used.

• Preprocessing parameters: These parameters are for changing thebehaviour in measurement preprocessing (e.g selecting a GEO).

• Model parameters: These parameters are for changing how the SBAScorrections are computed or applied (e.g changing the error bounds).

Page 48: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

28 New Input parameters and output messages in gLAB

• Filter parameters: These parameters are for changing the solutions to becomputed (e.g. enable the computation of the solutions for all geometriesfor Stanford-ESA plot).

• Output parameters: These parameters are for enabling SBAS messagefile type conversion or changing the name of the output files.

• Verbose parameters: These parameters are for changing which messagesare printed in the output file.

The full list of all parameters and its description can be found in Appendix A.1

4.2 Output messages

There are five new output messages for SBAS data plus an additional messagewith user-added error values (the possibility to add user-added error tomeasurements from the measurements was an additional ESA requirements,but it is not related in any way to MOPS). These six new messages are shownin the same order as gLAB prints them. This order reflects the several stagesfrom reading data to computing the navigation solution. The messages are thefollowing:

• USERADDEDERROR message: This message shows the error addedto each measurement for each satellite by the user. The error can begenerated by a step, ramp, sinusoidal or an Additive White GaussianNoise (AWGN) function. A text file is used to pass to gLAB how togenerate it (the parameter ’-usererrorfile <filename>’ outputs a helpmessage explaining how to create this file).

• SBASCORR message: This message shows the computed corrections.

• SBASVAR message: This message shows the computed error bounds.

• SBASIONO message: This message shows the computed ionospherecorrections and all the intermidiate values for computing the ionospherecorrection.

• SBASUNSEL message: This message shows the reason for discardinga satellite with a human readable text message.

• SBASOUT message: This message shows the solution computation, theprotection levels and the list of satellites used in the solution computation.

A detailed description of each message, explaining each field of each messagecan be found in Appendix A.2.

Page 49: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 5

gLAB usage examples withSBAS

In this chapter, in section 5.1 it is shown how to download the data for thecommand line examples in section 5.2. In section 5.2 it is shown a large numberof command line examples to execute gLAB in Linux, Windows and Cygwin (aLinux terminal emulator in Windows, which is provided with the Windows gLABinstallable file), so the user can rapidly start using the tool. In section 5.3, thetypical plots for SBAS are shown using some results from gLAB.

5.1 Data gathering for SBAS processing

The command line examples (in section 5.2) and plots (in section 5.3) arereferred to station ”vigo” in Day of Year (DoY) 165 (14th June) of year 2015.It is necessary to download three files: the observation file (with themeasurements from the receiver), the broadcast file (with the navigation datafrom the satellites) and the SBAS messages (which can be from any receiver,as the messages are broadcast for entire countries or continents). The files willbe downloaded from the following sites:

• Observation file: The GPS data receiver station is ”vigo” (shown inFig 5.1), which belongs to the European Reference Organisation forQuality Assured Breast Screening and Diagnostic Services (EUREF)permanent GNSS receiver network (see Bruyninx, C. (2004)). The 1 Hzobservation data file for any day can be downloaded from the URL:ftp://igs.bkg.bund.de/EUREF/highrate/

Page 50: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

30 gLAB usage examples with SBAS

• Navigation file: The GPS navigation data file can also be downloadedfrom European Reference Organisation for Quality Assured BreastScreening and Diagnostic Services (EUREF) network, but they areusually downloaded from Crustal Dynamics Data InformationSystem (CDDIS) network (see International GNSS Service Products(2014)). The URL for downloading the broadcast data is:ftp://cddis.gsfc.nasa.gov/pub/gps/data/daily/

• SBAS data file: The SBAS data file can be generated by any SBASreceiver in the same coverage area (a receiver is shown in Fig 5.2). Asthe selected receiver is in Vigo (Spain), we will use EGNOS messages.The RINEX-B files with EGNOS messages can be downloaded fromCentre National d’Etudes Spatiales (CNES) (see Centre Nationald’Etudes Spatiales (2016)) through the URLftp://serenad-public.cnes.fr/SERENAD0/FROM_NTMF/MSG/.

Figure 5.1: GPS receiver in Vigo from EUREF (2016).

Figure 5.2: Receiver from EGNOS network from Navipedia (2016).

Page 51: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

5.2. Command line examples 31

5.2 Command line examples

Usage examples in command line to run gLAB with SBAS data processing:

Standalone navigation with SBAS ionosphere (without any other SBAScorrection):

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbasiono M1201650.15b -model:iono SBAS > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasiono M1201650.15b -model:iono SBAS > outputfile.txt

Convert RINEX-B file to EMS and Pegasus format and exit without processing:Linux/Cygwin:

./gLAB linux -input:sbas M1201650.15b -output:ems -output:pegasus-onlyconvertWindows:

gLAB.exe -input:sbas M1201650.15b -output:ems -output:pegasus -onlyconvert

Convert RINEX-B file to Pegasus format (using space as column separator) andexit without processing:

Linux/Cygwin:./gLAB linux -input:sbas M1201650.15b -output:pegasus -

output:pegspace -onlyconvertWindows:

gLAB.exe -input:sbas M1201650.15b -output:pegasus -output:pegspace -onlyconvert

Convert RINEX-B file to Pegasus format (aligning all columns with spaces), exitwithout processing and write files Pegasus files in current directory:

Linux/Cygwin:./gLAB linux -input:sbas M1201650.15b -output:pegasus -

output:pegfilealign -output:sbasdir ”.” -onlyconvertWindows:

gLAB.exe -input:sbas M1201650.15b -output:pegasus -output:pegfilealign -output:sbasdir ”.” -onlyconvert

Page 52: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

32 gLAB usage examples with SBAS

Convert RINEX-B file to Pegasus format (using space as column separator andaligning all columns with spaces) and exit without processing:

Linux/Cygwin:./gLAB linux -input:sbas M1201650.15b -output:pegasus -

output:pegspace -output:pegfilealign -onlyconvertWindows:

gLAB.exe -input:sbas M1201650.15b -output:pegasus -output:pegspace -output:pegfilealign -onlyconvert

Standard SBAS processing:Linux/Cygwin:Windows:

./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b > outputfile.txt

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b > outputfile.txt

Standard SBAS processing with file conversion from RINEX-B to Pegasus:Linux/Cygwin:

./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b -output:pegasus > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -output:pegasus > outputfile.txt

Standard SBAS processing printing only SBASOUT messages:Linux/Cygwin:

./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b -print:none -print:sbasout > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -print:none -print:sbasout > outputfile.txt

Standard SBAS processing enabling the step detector and also computing theStanford-ESA plot values:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -filter:stfdesa -filter:stepdetector > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -filter:stfdesa -filter:stepdetector > outputfile.txt

NOTE: The Stanford-ESA plot values will be written in the file”<observationfilename> stdESA” (which in this case would be”vigo1650.15o stdESA”)

Page 53: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

5.2. Command line examples 33

Standard SBAS processing computing the Stanford-ESA plot values with theoutput file for Stanford-ESA plot values as ”std-ESA-madr”,and set themaximum values for the ’x’ axis (error axis) to 40 meters, the ’y’ axis(protection level) to 70 meters, the ’x’ pixel resolution to 1 meter and the ’y’pixel resolution to 1 meter:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -filter:stfdesa -output:stfdesa ”std-ESA-madr”-filter:stfdesa:xmax 40 -filter:stfdesa:ymax 60 -filter:stfdesa:xres 1 -filter:stfdesa:yres 1 > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b -filter:stfdesa -output:stfdesa ”std-ESA-madr”-filter:stfdesa:xmax 40 -filter:stfdesa:ymax 60 -filter:stfdesa:xres 1 -filter:stfdesa:yres 1 > outputfile.txt

SBAS processing disabling the steady state operation for smoothing anddecimating at a 30 second rate:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -pre:dec 30 -pre:smoothmin 0 > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -pre:dec 30 -pre:smoothmin 0 > outputfile.txt

SBAS processing using the GEO with highest elevation, enabling SNRdeselection to all GPS satellites with a threshold of 38 dBHz and fixing theσmultipath of the airborne receiver to 5 meters:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -pre:geosel 2 -pre:snr -pre:snrsel G0 38 -model:sigmpath 5 0 > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -pre:geosel 2 -pre:snr -pre:snrsel G0 38 -model:sigmpath 5 0> outputfile.txt

Page 54: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

34 gLAB usage examples with SBAS

SBAS processing with timeout for message type 26 to 10 minutes in NPA,timeout for fast corrections of 30 seconds in both PA and NPA, timeout forrange rate corrections to 40 seconds in PA, enabling mode switching, setting theσmultipath of the receiver to a fixed value of σmultipath = 5+3e(−satelevation/10),the σdivergence to a fixed value of 10 meters and the σnoise to 13 meters:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -model:sbastmoutnpa 26 600 -model:sbastmoutfc30 -model:sbastmoutrrcpa 40 -model:sbasmodeswitch -model:sigmpath 5 3-model:sigdiv 10 -model:signoise 13 > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -model:sbastmoutnpa 26 600 -model:sbastmoutfc 30 -model:sbastmoutrrcpa 40 -model:sbasmodeswitch -model:sigmpath 5 3 -model:sigdiv 10 -model:signoise 13 > outputfile.txt

SBAS processing enabling GEO switch and mode switch, deselecting GEO 136,selecting GEO 120 as primary GEO, ignore type 0 messages and setting theGEO acquisition time to 100 seconds and the switch time to 10 seconds:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -model:geoswitch -model:sbasmodeswitch -pre:geoexclude 136 -pre:geosel 120 -model:ignoretype0 -model:geoadqtime100 -model:switchtime 10 > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b -model:geoswitch -model:sbasmodeswitch-pre:geoexclude 136 -pre:geosel 120 -model:ignoretype0 -model:geoadqtime100 -model:switchtime 10 > outputfile.txt

SBAS processing in NPA mode, treating MT0 as MT2, using data from mixedGEO and enabling the step detector:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n

-input:sbas M1201650.15b -model:sbasmode NPA -pre:geosel 0 -filter:stepdetector > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -model:sbasmode NPA -pre:geosel 0 -filter:stepdetector >outputfile.txt

Page 55: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

5.2. Command line examples 35

SBAS processing enabling GEO switch, enabling GEO switch to mixed GEOdata, setting timeout for MT10 to 100 seconds for both PA and NPA andsetting the SBAS receiver to type 1:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n

-input:sbas M1201650.15b -model:geoswitch -model:mixedgeo -model:sbastmout 10 100 -model:sbasreceiver 1 > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -model:geoswitch -model:mixedgeo -model:sbastmout 10 100-model:sbasreceiver 1 > outputfile.txt

Show help message and an example on how to create a user-defined error filefor adding error to raw measurements:

Linux/Cygwin:./gLAB linux -usererrorfile

Windows:gLAB.exe -usererrorfile

Show help message and an example on how to create a user-defined sigmamultipath model:

Linux/Cygwin:./gLAB linux -sigmamultipathfile

Windows:gLAB.exe -sigmamultipathfile

SBAS processing with user-defined error:Linux/Cygwin:

./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b -input:usererror usererrorfile > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -input:usererror usererrorfile > outputfile.txt

SBAS processing with user-defined sigma multipath model:Linux/Cygwin:

./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbas M1201650.15b -input:sigmpath usersigmamultipathmodelfile >outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -input:sigmpath usersigmamultipathmodelfile > outputfile.txt

Page 56: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

36 gLAB usage examples with SBAS

SBAS processing with user-defined sigma multipath model, user-defined error,σdivergence to a fixed value of 10 meters and the σnoise to 13 meters:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -input:sigmpath usersigmamultipathmodelfile -input:usererror usererrorfile -model:sigdiv 10 -model:signoise 13 >outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -input:sigmpath usersigmamultipathmodelfile -input:usererrorusererrorfile -model:sigdiv 10 -model:signoise 13 > outputfile.txt

SBAS processing but using IONEX ionosphere model instead of SBASionosphere model:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -input:inx igrg1650.15i -model:iono IONEX >outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -input:inx igrg1650.15i -model:iono IONEX > outputfile.txt

SBAS processing but disabling all ionosphere model (including SBAS) and withuser-defined sigma multipath model:

Linux/Cygwin:./gLAB linux -input:obs vigo1650.15o -input:nav brdc1650.15n -

input:sbas M1201650.15b -input:sigmpath usersigmamultipathmodelfile --model:iono > outputfile.txtWindows:

gLAB.exe -input:obs vigo1650.15o -input:nav brdc1650.15n -input:sbasM1201650.15b -input:sigmpath usersigmamultipathmodelfile --model:iono >outputfile.txt

Page 57: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

5.3. SBAS Figures of Merit 37

5.3 SBAS Figures of Merit

After processing data using SBAS, the next step is to analize the results byplotting. The output messages provide detailed level of information, but thetypical plots after processing SBAS are the following:

• NEU error plot: This plot depicts the North East Up (NEU) errorcomponents with respect to time for each navigation solution computed.

• HE and HPL: This plot compares the values of the Horizontal Error (HE)and the Horizontal Protection Level (HPL) for each navigation solutioncomputed.

• VE and VPL: This plot compares the values of the Vertical Error (VE)and the Vertical Protection Level (VPL) for each navigation solutioncomputed.

• Stanford plot: This plot depicts the horizontal axis as the errorcomponent and the vertical axis as the protection level. The plot ismade out of pixels, whose colour indicate how many points (epochs)occur in those coordinates. In this way, it is easy to see if there are errorvalues over the protection level and how the epoch solution isdistributed. Two Stanfords plots have to be done, one for the horizontalerror and horizontal protection level, and another for the vertical errorand vertical protection level.

• Stanford-ESA plot: The same as the Stanford plot, but in this casethe plots includes all the navigation solutions for all possible geometriesin each epoch (i.e. computing all the navigation solution with all thepossible satellites in view in each epoch). A complete review of Stanford-ESA can be found in Ventura-Traveset, J. and Flament (2006).

These plots can be done with any powerful plotting tool, such as for exampleGNUplot, which is the default tool in Linux systems. In order to make gLABa self contained tool, a plotting tool (graph) is also given, which has beendeveloped by the Research group of Astronomy and Geomatics (gAGE). All theplots shown below have been done with graph.

Page 58: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

38 gLAB usage examples with SBAS

The plots in Fig 5.3 show the positioning error in north, east and up componentsfor both modes, without SBAS corrections and with SBAS corrections. We canclearly see that the error with SBAS stays under 2 meters during most of the day,while in SPP the error varies more than 5 meters. In Fig 5.3b there is an errorpeak at second 41230 approximately, which does not appear in Fig 5.3a. Thisis because at this epoch, three satellites have cycle-slip, and after a cycle-slip,SBAS processing needs to wait for 360 seconds for the smoothing to convergefor using the satellite again in the solution computation, while in SPP there isno need to wait for the smoothing to converge.

(a) NEU error without SBAS corrections (b) NEU error with SBAS corrections

Figure 5.3: Positioning error with and without SBAS

The plots in Fig 5.4 show that the protection levels adequately bound thenavigation error as expected, due to as the error increases, the protection levelalso increases, but in a higher rate.

(a) HE and HPL (b) VE and VPL

Figure 5.4: Error and protection levels

Page 59: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

5.3. SBAS Figures of Merit 39

The plots in Fig 5.5 show the Stanford plots for the horizontal (Fig 5.5a) andvertical (Fig 5.5b) components. We can clearly see that the values are far fromthe diagonal line where the error equals the protection level. Systems havingthis property are conservative, because SBAS systems are designed for safety oflife services.

(a) Stanford plot for horizontal components (b) Stanford plot for vertical components

Figure 5.5: Stanford plots

The plots in Fig 5.6 show the Stanford-ESA plot for the horizontal (Fig 5.6a)and vertical (Fig 5.6b) components. With these plots, we can assure that inany case (any geometry used for the solution computation), the user will neverhave any geometry in which the error is higher than the protection level. Asa comparison between Stanford plot and Stanford-ESA plot, the number ofgeometries (shown in the title of Fig 5.5) is larger than seventy-nine thousand,while in Stanford-ESA plot the number of geometries is larger than thirty-fivemillion (shown in the title of Fig 5.6b), which is a factor of more than onethousand.

(a) Stanford-ESA plot for horizontalcomponents

(b) Stanford-ESA plot for verticalcomponents

Figure 5.6: Stanford-ESA plots

Page 60: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 61: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 6

gLAB applications and futurework

As this upgrade gLAB has been developed within an ESA contract, in thiscontract applications for this software were also foreseen. Furthermore, thereare planned future updates for this tool. These applications and updates areexplained in this chapter.

6.1 Applications

The main use for this new version is gLAB is for a monitoring system for EGNOS.A monitoring system is an autonomous server that automatically downloadsSBAS data, processes it, and the results are statistically analized for each day.The computations are done in post-process with a latency of two days (so it issure that the receiver network has had time to upload the 24h data file from thereceiver to their public servers). Moreover, for easy access to the results, theserver has a webserver (accessible through the internet). The goal is to createa new monitoring system using gLAB for processing EGNOS data very similarto the one shown in Fig 6.1. The plots that will be available in the webpagewill be the ones already shown in chapter 5.3.

Page 62: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

42 gLAB applications and future work

Figure 6.1: EGNOS gAGE/UPC monitoring system. In this screenshot the plotsfor integrity and accuracy values for the 29th December 2015 are shown.

Page 63: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

6.2. Future work 43

6.2 Future work

The following tasks are planned to be carried out in already started projects orprojects pending approval, all of them with ESA:

• Graphical User Interface (GUI): A Contract ChangeNotification (CCN) has already been issued to the current gLAB projectfor SBAS in order to extend the current GUI with SBAS.

• Educational courses: Once the new GUI is finished, gLAB SBAScapabilities will be used for educational purposes, for both students andprofessionals.

• Dual frequency SBAS: The new version of SBAS is currently beingdesigned, with one of most important features being the capability towork in dual frequency (L1 and L5). The objective will be to implementthe current development version in gLAB and use it in the validation phaseof this new version of EGNOS.

• Galileo: EGNOS is planning to broadcast corrections for Galileo whenthis constellation reaches FOC. gLAB will be updated in order to includealso Galileo in SBAS processing.

Page 64: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 65: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 7

Publications using gLAB

During my work in gLAB, in previous projects (see Ibanez, D. (2014)) and thecurrent one, gLAB has proven to be a very useful tool for computing resultsused later for publishing papers. In this chapter all the publications in which Iappear as author or coauthor and gLAB has been used will be listed.

The first one is my previous update of gLAB, in which I added NeQuick, Fast-PPP and IGS-GIM GNSS ionospheric models. It is worth mentioning that thishas been read or downloaded from fifty-three different countries (these statisticsare publicly available in the publication website shown in the citation):

• Ibanez, D (2014) Implementation of GNSS Ionospheric models in gLAB.URL http://upcommons.upc.edu/handle/2099.1/24770

The previous update was key for the following publications (one peer-reviewedjournal article -the first entry- and five conference proceedings), due to thefact that all of them are related to ionospheric model studies or the impactof ionosphere model quality on the navigation solution. The papers are thefollowing:

1. Rovira-Garcia A, Juan J, Sanz J, Gonzalez-Casado G, Ibanez Segura D(2015b) Accuracy of Ionospheric Models used in GNSS and SBAS:Methodology and Analysis. Journal of Geodesy 90(3):229–240, doi:{10.1007/s00190-015-0868-3}, URLhttp://dx.doi.org/10.1007/s00190-015-0868-3

2. Rovira-Garcia A, Juan M, Sanz J, Gonzalez-Casado G, Ibanez Segura D,Romero-Sanchez (2015d) Assessment of Ionospheric Models for GNSSDuring a Year of Solar Maximum. In: Proceedings of ION GNSS+ 2015,Tampa, Florida (USA), pp 3833–3840, URL http://www.ion.org/

publications/abstract.cfm?jp=p&articleID=13088

Page 66: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

46 Publications using gLAB

3. Rovira-Garcia A, Juan J, Sanz J, Gonzalez-Casado G, Ibanez Segura D(2015c) Assessment of Ionospheric Models Tailored for Navigation. In:SBAS Ionospheric Working Group Meeting 22, Trieste, Italy

4. Rovira-Garcia A, Juan J, Sanz J, Gonzalez-Casado G, Ibanez Segura D(2015a) A Methodology to Assess Ionospheric Models for GNSS. In:Proceedings of the European Geosciences Union General Assembly 2015Geophysical Research Abstracts Vol. 17, Vienna, Austria, URL http://

meetingorganizer.copernicus.org/EGU2015/EGU2015-1015.pdf

5. Juan M, Sanz J, Gonzalez-Casado G, Rovira-Garcia A, Ibanez Segura D,Orus-Perez R, Prieto-Cerdeira R, Schlueter S (2014) Accurate referenceionospheric model for testing GNSS ionospheric correction in EGNOSand Galileo. In: Proceedings of the 7th ESA Workshop on SatelliteNavigation Technologies: Era of Galileo IOV (NAVITEC 2014),ESA/ESTEC, Noordwijk, The Netherlands, URLhttp://gage6.upc.es/gAGE_WEB/papers/2014/73415_Juan.pdf

6. Vinh L, Quang PX, Garcia-Rigo A, Rovira-Garcia A, Ibanez Segura D(2013) Experiments on the Ionospheric Models in GNSS. In: Proceedingsof 20th Asia-Pacific Regional Space Agency Forum, Hanoi, Vietnam, vol113

Page 67: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Chapter 8

Conclusion

In this final degree project the gLAB tool (described in chapter 2) was upgradedin order to use messages from SBAS systems in GNSS positioning. Both systemshave been introduced, the former in chapter 3 and the latter in chapter 1.

During the programming phase, it should be noted that the source codestructure and design of gLAB has proved to be a flexible and fully prepared formajor upgrades, although being a source code with about 20.000 lines. Itsmodular design, with different source code files for the various parts of theprocessing (for example one file just for functions for modelling measurements,another just for output messages, etc.), makes it much easier for anyprogrammer to understand the code and add the necessary changes.

In the test phase, gLAB computed values were checked with two independenttools: the Basic research utilities for SBAS NAVigation module (BNAV),developed in the Research group of Astronomy and Geomatics (gAGE), andthe Prototype EGNOS and GBAS Analysis System UsingSAPPHIRE (Pegasus), developed by Eurocontrol. Having access to BNAVsource code greatly helped in the debugging, while the use of Pegasus (whosesource code is not available) as a second validation tool helped find commonerrors between gLAB and BNAV.

In chapter 5 a very large amount of command line examples are presented. It isimportant to emphasize that, for normal SBAS processing, the only parametersneeded by gLAB are the input files, which makes it very simple for any user toget started with the tool, even though the large number of available parametersand the large output messages detailed in appendix A.

Last but not least, in chapter 7 it is shown that gLAB is an important tool forpublications. Therefore, this upgrade of gLAB will allow further publicationsfocused on SBAS.

Page 68: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 69: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Appendix A

SBAS Input parameters andoutput messages

A.1 Input parameters

A.1.1 Help parameters

These are the parameters to display help messages:

-usererrorfile Shows an example of user-defined errorconfiguration file

-sigmamultipathfile Shows an example of user multipath modelconfiguration file

Table A.1: Help parameters

A.1.2 Input parameters

These are the input parameters:

-input:sbas <file> Sets the SBAS data file (RINEX-B v2.11 orEMS). Activates SBAS processing mode

-input:sbasiono <file> Sets the input RINEX-B or EMS SBAS filefor ionospheric corrections. It does notactivate SBAS processing mode

-input:sigmpath <file> Sets the data file for user sigma multipathmodel for SBAS (execute ’gLAB -sigmamultipathfile’ for details)

Page 70: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

50 SBAS Input parameters and output messages

-input:usererror <file> Sets the data file for adding user definednoise signal to raw measurements (execute’gLAB -usererrorfile’ for details)

Table A.2: Input parameters

A.1.3 Preprocessing parameters

These are the preprocessing parameters:

-pre:geoexclude # Exclude GEO satellite from SBAS. Datafrom this GEO will be ignored for SBAScorrections# = PRN number

-pre:geosel # Select GEO satellite for SBAS corrections# = 0 Use data from all GEO (all GEOmixed) [default in NPA if mixing GEO datais enabled]# = 1 Use GEO from the first line ofSBAS data read [default in PA]# = 2 Use the GEO with highest elevation120 <= # <= 210 Use the GEO with thegiven PRN

-pre:snr Enable Signal to Noise Ratio (SNR)deselection. The SNR is read from theobservation file. [default off]. If noSNR is present in the observation file, nodeselection is done. The default thresholdis 35 dBHz

-pre:snrsel g# <val> Set a SNR threshold for a given satellite.If this option is given, SNR deselection willbe activatedg = character determining GNSS system(G->GPS)# = PRN number. If #=0, then thethreshold will be applied to all satellites ofthe selected GNSS system<val> Value for SNR threshold in dBHz.This value is compared to the SNRobtained from the RINEX file in all codeand carrier phase measurements. If noSNR value is present in the RINEX file, thisvalue will be omitted

Page 71: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.1. Input parameters 51

-pre:smoothmin <val> Number of seconds of continuous codesmoothing before steady-state operation[default 0 for non SBAS processing, 360for SBAS processing]. Satellites will beexcluded until reaching this steady-state

Table A.3: Preprocessing parameters

A.1.4 Model parameters

These are the model parameters:

-model:iono <val> <val>= no Do not correct ionosphere[default in PPP] (equivalent to ’--model:iono’)<val>= Klobuchar Correctmeasurements with Klobuchar model[default in SPP]<val>= BeiDou Correct measurementswith BeiDou model<val>= IONEX Correct measurementswith IONEX file data<val>= FPPP Correct measurementswith Fast Precise Point Positioning (Fast-PPP) file data<val>= NeQuick Correct measurementswith NeQuick model<val>= SBAS Correct measurementswith SBAS iono corrections (but do notapply any other SBAS correction)

-model:alarmmsgtype2 When reading an SBAS message type 0,parse it as type 2 [default off]

-model:ignoretype0 Ignore all SBAS messages type 0 [defaultoff]

-model:sbasmode <val> Select navigation mode for SBASprocessing:<val>= PA Precision Approach [default]<val>= NPA Non Precision Approach

-model:geoswitch Enable GEO switch for SBAS processing[default off]

Page 72: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

52 SBAS Input parameters and output messages

-model:geofallback If GEO switch for SBAS is enabled, alwaystry to return to the initial selected GEO[default off]By default, gLAB will try to keepthe same GEO during SBAS processing,independently of how it has been selected

-model:sbasmodeswitch Enable navigation mode switching forSBAS processing [default off]

-model:sbasreceiver # Set receiver class type for SBAS (forcomputing variance of the airbornereceiver)# = 0 User defined receiver model (givenin file with parameter ’-input:sigmpath’)# = 1 Class 1 equipment# = 2,3,4 Class 2,3,4 equipment (allequivalent) [default 2]

-model:geoadqtime # Set the minimum time (in seconds) toconsider that gLAB has received enoughSBAS corrections from a GEO countingfrom the first message received [default300]This timer is set to ensure that gLAB hasreceived enough corrections from the GEOwe want to switch to. If this timer is settoo low (few seconds), it may happen thatgLAB switches to a GEO with not enoughdata (due to gLAB is in initialization or theGEO has received an alarm message)

-model:switchtime # Set the minimum time (in seconds)between a GEO or mode switch and thefollowing one [default 20]This timer is set to avoid continuousswitching in the same epoch when all GEOdo not have enough data. If this timeris set to zero, a maximum of 2 switchesper epoch (for both mode and GEO) areallowed

-model:sbastmout <n><val>

Set timeout value for SBAS messages(except for fast and range rate corrections)in both modes, PA and NPA<n> is the message type number<val> is the timeout value (in seconds)

Page 73: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.1. Input parameters 53

-model:sbastmoutpa <n><val>

Set timeout value for SBAS messages(except for fast and range rate corrections)in PA mode<n> is the message type number<val> is the timeout value (in seconds)

-model:sbastmoutnpa <n><val>

Set timeout value for SBAS messages(except for fast and range rate corrections)in NPA mode<n> is the message type number<val> is the timeout value (in seconds)

-model:sbastmoutfc <val> Set timeout value for fast corrections inboth modes, PA and NPA<val> is the timeout value (in seconds)

-model:sbastmoutfcpa<val>

Set timeout value for fast corrections in PA<val> is the timeout value (in seconds)

-model:sbastmoutfcnpa<val>

Set timeout value for fast corrections inNPA<val> is the timeout value (in seconds)

-model:sbastmoutrrc <val> Set timeout value for range rate correctionsin both modes, PA and NPA<val> is the timeout value (in seconds)

-model:sbastmoutrrcpa<val>

Set timeout value for range rate correctionsin PA<val> is the timeout value (in seconds)

-model:sbastmoutrrcnpa<val>

Set timeout value for range rate correctionsin NPA<val> is the timeout value (in seconds)

-model:sigmpath <val1><val2>

Set parameters a,b for sigma multipathfor SBAS airborne receiver, beingsigma=a+b∗eˆ(-satelevation/10) and theelevation in degrees<val1> a value (in metres)<val2> b value (in metres)

-model:sigdiv <val> Set a fixed value (in metres) for sigmadivergence for SBAS airborne receiver

-model:signoise <val> Set a fixed value (in metres) for sigma noisefor SBAS airborne receiver

Table A.4: Model parameters

NOTE: If no timeout values are set, the default MOPS values fromRTCA-MOPS (2006) will be set.

Page 74: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

54 SBAS Input parameters and output messages

A.1.5 Filter parameters

These are the filter parameters:

-filter:stepdetector Check for jumps in measurements using theprefit residuals [default off]

-filter:stfdesa Compute values for Stanford-ESA plot(only available for SBAS processing)[default disabled].The output data is written in a separate file(which has to be processed with graph.py).See parameter ’-output:stfdesa’

-filter:stfdesa:xmax <val> Sets the maximum value for the horizontalaxis (error axis, in metres) for Stanford-ESA plot [default 50]

-filter:stfdesa:ymax <val> Sets the maximum value for the verticalaxis (protection level axis, in metres) forStanford-ESA plot [default 50]

-filter:stfdesa:xres <val> Sets the horizontal resolution (error axis, inmetres) for Stanford-ESA plot [default 0.1]

-filter:stfdesa:yres <val> Sets the vertical resolution (protection levelaxis, in metres) for Stanford-ESA plot[default 0.1]

Table A.5: Filter parameters

A.1.6 Output parameters

These are the output parameters:

-output:rinexb Generate a RINEX-B file without incorrectmessages (see note below) from the SBASdata (only for SBAS) [default off]

-output:ems Generate a EMS file without incorrectmessages (see note below) from the SBASdata (only for SBAS) [default off]

-output:pegasus Generate Pegasus file format from theSBAS data (only for SBAS) [default off]

-output:pegstrictrinex When generating a RINEX-H file forPegasus, follow the RINEX 2.11 rules fortransmission time, health flag and URA(only active if -output:pegasus has beenset) [default off]

Page 75: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.1. Input parameters 55

-output:pegspace Set the field separator in Pegasus files tospace character (’ ’) instead of a semicolon(’;’) [default off]

-output:pegfilealign Print Pegasus files with all columns aligned[default off]

-output:sbasdir <name> Set the directory name where to write theoutput SBAS files (’.’ for current directory)[default “SBAS”]

-output:stfdesa <name> Set the filename where to write the outputdata for Stanford-ESA plots [default“observationfilename stdESA”].The output file has to be processed withgraph.py to generate the Stanford-ESAplots

-onlyconvert Convert EMS or RINEX-B file to RINEX-B, EMS or Pegasus and exit withoutprocessing any GNSS data [default off]

Table A.6: Output parameters

NOTE: Incorrect messages from RINEX-B or EMS files are messages whichfulfill any of these conditions: Cyclic Redundancy Check (CRC) mismatch,invalid header, unknown message type, invalid time of applicability (timeexceeds 86400 seconds).

A.1.7 Verbose parameters

These are the verbose parameters:

-print:sbascor Print SBASCORR messages (only forSBAS) [default off]

-print:sbasvar Print SBASVAR messages (only for SBAS)[default off]

-print:sbasiono Print SBASIONO messages (only forSBAS) [default off]

-print:sbasout Print SBASOUT messages (only for SBAS)[default on]

-print:sbasunsel Print SBASUNSEL messages (only forSBAS) [default off]

Page 76: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

56 SBAS Input parameters and output messages

-print:sbasunused Print messages from discarded satellitesdue to SBAS GEO switch (only for SBAS)[default off]The discarded messages are MODEL,SBASCORR, SBASVAR, SBASIONO andSBASUNSEL, but only the ones selectedfrom user parameters will be printed. Also,an asterisk ’*’ will be added at the endof the first field to indicate that it is adiscarded measurement

-print:usererror Print user added error to rawmeasurements [default on]

Table A.7: Verbose parameters

NOTE: Use -print:... to activate, --print:... to deactivate.

Page 77: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 57

A.2 Output messages

A.2.1 USERADDEDERROR message

User-defined error added to measurements before cycle-slip detection andsmoothing.

# FIELD DESCRIPTION UNITS1 USERADDEDERROR Fixed word indicating the data

stored.-

2 Year Year number (4 digits). years

3 DoY Day of Year (3 digits). days

4 Seconds of day Seconds elapsed since thebeginning of the day.

seconds

5 GPS week Week number in GPS Time. Thisfield is related to the GPS weekof the data snapshot used for thecomputations.

weeks

6 Time of week Seconds elapsed since thebeginning of the week. Thisfield is related to the GPS numberof seconds of the data snapshotused for the computations.

seconds

7 GNSS system Satellite constellation (GPS, GAL,GLO or GEO).

-

8 PRN Satellite identifier. -

9 Measurementidentifier

String with the measurementobservation code.

-

10 Measuredpseudorange

Value of the measured pseudorange(phase measurements areprealigned).

metres

11 Measuredpseudorange withuser-defined error

Value of the measured pseudorange(phase measurements areprealigned) with the total user-defined error.

metres

12 Active user-definederror functions

Total number of active user-definederrors functions (Step, Ramp,Sinusoidal and Additive WhiteGaussian Noise (AWGN)) in thecurrent epoch.

-

13 Total user-definederror functions

Total user-defined error in thecurrent epoch.

metres

Page 78: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

58 SBAS Input parameters and output messages

14 Active Step functionerror

Number of active Step functionerrors in the current epoch.

-

15 Step function errorvalue

Sum of all Step function errors inthe current epoch.

metres

16 Active Ramp functionerror

Total number of active Rampfunction errors in the currentepoch.

-

17 Ramp function errorvalue

Sum of all Ramp function errors inthe current epoch.

metres

18 Active Sinusoidalfunction error

Number of active Sinusoidalfunction errors in the currentepoch.

-

19 Sinusoidal functionerror value

Sum of all Sinusoidal functionerrors in the current epoch.

metres

20 Active AWGN functionerror

Number of active AWGN functionerrors in the current epoch.

-

21 AWGN function errorvalue

Sum of all AWGN function errors inthe current epoch.

metres

Table A.8: USERADDEDERROR message

A.2.2 SBASCORR message

SBAS corrections breakdown. It is shown when a model can be fully computedusing SBAS corrections for GPS C1C measurement.

# FIELD DESCRIPTION UNITS1 SBASCORR Fixed word indicating the data

stored.-

2 Receiver id Receiver identification. -

3 Mode SBAS processing mode: PA, NPA. -

4 GNSS system Satellite constellation (GPS, GAL,GLO or GEO).

-

5 PRN Satellite identifier. -

6 Year Year number (4 digits). years

7 DoY Day of Year (3 digits). days

8 Seconds of day Seconds elapsed since thebeginning of the day.

seconds

9 GPS week Week number in GPS Time. Thisfield is related to the GPS weekof the data snapshot used for thecomputations.

weeks

Page 79: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 59

10 Time of week Seconds elapsed since thebeginning of the week. Thisfield is related to the GPS numberof seconds of the data snapshotused for the computations.

seconds

11 GEO PRN GEO from which the SBAScorrections are used (’0’ means allGEOs)

-

12 Prefit Residual pseudorange value(measurement − model) used asprefit residual for the satellite.

metres

13 Measuredpseudorange (C1Craw)

Value of the measured pseudorange(C1C raw).

metres

14 Measuredpseudorange (C1Csmoothed)

Value of the measured pseudorangeafter smoothing (C1C smoothed).

metres

15 Geometric range (ρ) Geometric distance between thesatellite and the receiver location(with SBAS corrections).

metres

16 Relativistic delay Delay associated to relativisticeffects (with SBAS corrections).

metres

17 Satellite clock offset It includes the clock offsetcorrection broadcast by thesatellite itself together with thesatellite clock offset broadcast inthe Long Term Corrections for thesatellite.

metres

18 Total group delay(TGD)

Delay associated to the groupof GPS satellites. From GPSnavigation message.

metres

19 IPP Latitude Latitude corresponding to theIonospheric Pierce Point (IPP) usedto compute the ionospheric delay.

degrees(-90-90◦)

20 IPP Longitude Longitude corresponding to theIonospheric Pierce Point (IPP) usedto compute the ionospheric delay.

degrees(0-360◦)

21 Ionospheric delay Delay associated to ionosphericeffects.

metres

22 Tropospheric delay Delay associated to troposphericeffects.

metres

Page 80: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

60 SBAS Input parameters and output messages

23 PRC Pseudorange correction to beapplied to the satellite modelling.

metres

24 RRC Range rate correction to be appliedto the satellite modelling.

metres

25 ai factor Fast Correction degradation factorfrom message type 7.

metres/seconds2

26 PRC timeout Timeout interval for currentpseudorange correction.

seconds

27 RRC timeout Timeout interval for current rangerate correction (smallest PRCtimeout for all satellites).

seconds

28 PRC time reference Time (seconds of day) used forcomputing PRC timeout.

seconds

29 UDRE time reference Time (seconds of day) used forcomputing sigma User DifferentialRange Error (UDRE) timeout.

seconds

30 Fast correctiondegradation timereference

Time (seconds of day) usedfor computing fast correctiondegradation.

seconds

31 X Sat pos X component of the satelliteposition in WGS-84 systemat emission time with SBAScorrections.

metres

32 Y Sat pos Y component of the satelliteposition in WGS-84 systemat emission time with SBAScorrections.

metres

33 Z Sat pos Z component of the satelliteposition in WGS-84 systemat emission time with SBAScorrections.

metres

34 ∆X Long-term correction to be appliedto the X component of the satellite.

metres

35 ∆Y Long-term correction to be appliedto the Y component of the satellite.

metres

36 ∆Z Long-term correction to be appliedto the Z component of the satellite.

metres

37 ∆t Long-term correction to be appliedto the satellite clock.

metres

38 IODP fast corrections Issue Of Data PRN mask (IODP)used for fast corrections. If noIODP is available, the value is -1.

-

Page 81: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 61

39 IODF Issue Of Data Fast Correction(IODF) in messages type 2-5, 24for fast corrections. If no IODF isavailable, the value is -1.

-

40 Fast correctionsatellite slot

Satellite slot in the fast correctionmask (1-51). If no IODP isavailable, the value is -1. The slotindicates the satellite position inthe fast correction message.

-

41 IODP long termcorrections

IODP used for long termcorrections. If no IODP isavailable, the value is -1

-

42 Long-term correctionssatellite slot

Satellite slot in the long termcorrection mask (1-51). If noIODP is available, the value is -1. The slot indicates the satelliteposition in the long term correctionmessage.

-

43 IODE Issue Of Data Ephemerides (IODE)used for broadcast ephemeris. Ifno IODE is available, the value is999. If an IODE is used that doesnot match the one broadcast in thelong term corrections (only in NPAmode), the value will negative.

-

44 IODS Service Issue Of Data (IODS) usedfor service message. If no IODS isavailable or it is not used, the valueis -1.

-

45 IODP clock-ephemeriscovariance matrix

IODP used for clock-ephemeriscovariance matrix. If no IODP isavailable or it is not used, the valueis -1.

-

46 Clock-ephemeriscovariance matrix slot

Satellite slot in the clock-ephemeriscovariance mask (1-51). If noIODP is available or it is not used,the value is -1. The slot indicatesthe satellite position in the clock-ephemeris message.

-

Page 82: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

62 SBAS Input parameters and output messages

47 Ionosphere model flag Flag to indicate which ionospheremodel is used. Its possible valuesare ’-1’ for no ionosphere model, ’0’for SBAS ionosphere model, ’1’ forKlobuchar ionosphere model and’2’ for any other ionosphere model.

-

48 Elevation Elevation angle between thesatellite and the receiver location.

degrees

49 Azimuth Azimuth angle between the satelliteand the receiver location.

degrees

Table A.9: SBASCORR message

A.2.3 SBASVAR message

SBAS variance contributions breakdown. It is shown when a model can be fullycomputed using SBAS corrections for GPS C1C measurement.

# FIELD DESCRIPTION UNITS1 SBASVAR Fixed word indicating the data

stored.-

2 Receiver id Receiver identification. -

3 Mode SBAS processing mode: PA, NPA. -

4 GNSS system Satellite constellation (GPS, GAL,GLO or GEO).

-

5 PRN Satellite identifier. -

6 Year Year number (4 digits). years

7 DoY Day of Year (3 digits). days

8 Seconds of day Seconds elapsed since thebeginning of the day.

seconds

9 GPS week Week number in GPS Time. Thisfield is related to the GPS weekof the data snapshot used for thecomputations.

weeks

10 Time of week Seconds elapsed since thebeginning of the week. Thisfield is related to the GPS numberof seconds of the data snapshotused for the computations.

seconds

11 GEO PRN GEO from which the SBAScorrections are used (’0’ means allGEOs)

-

Page 83: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 63

12 σtotal Sigma of the total residual errorassociated to the satellite.

metres

13 σflt Sigma of the residual errorassociated to the fast and long-term corrections.

metres

14 σUDRE Sigma of the User DifferentialRange Error (UDRE)

metres

15 δUDRE Delta User Differential Range Error(UDRE)

-

16 δUDRE data source Data source (SBAS message typenumber) for δUDRE . It may havethe following values: 27 or 28for their respective message type,-27 or -28 if received any ofthese message types but there wasmissing data for current satellite orwas timed out, 0 if no message typereceived or both received.

-

17 εfc Degradation parameter for fastcorrection data.

metres

18 εrrc Degradation parameter for rangerate correction data.

metres

19 εltc Degradation parameter for longterm correction data or GEOnavigation message data.

metres

20 εer Degradation parameter for en-routethrough NPA applications.

metres

21 RSSUDRE Root Sum Square (RSS) flag inmessage type 10.

-

22 σUIV E Sigma of the residual errorassociated to the ionosphericcorrections.

metres

23 σtropo Sigma of the residual errorassociated to the troposphericcorrections.

metres

24 σair Sigma of the total airborne receivererror.

metres

25 σnoise Sigma of the airborne receivernoise.

metres

26 σmultipath Sigma of the airborne receivermultipath.

metres

Page 84: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

64 SBAS Input parameters and output messages

27 σdivg Sigma of the airborne receiverdivergence.

metres

28 Elevation Elevation angle between thesatellite and the receiver location.

degrees

29 Azimuth Azimuth angle between the satelliteand the receiver location.

degrees

Table A.10: SBASVAR message

A.2.4 SBASIONO message

SBAS ionosphere breakdown. It is shown when SBAS ionosphere can becomputed.

# FIELD DESCRIPTION UNITS1 SBASIONO Fixed word indicating the data

stored.-

2 Receiver id Receiver identification. -

3 Mode SBAS processing mode: PA, NPA. -

4 GNSS system Satellite constellation (GPS, GAL,GLO or GEO).

-

5 PRN Satellite identifier. -

6 Year Year number (4 digits). years

7 DoY Day of Year (3 digits). days

8 Seconds of day Seconds elapsed since thebeginning of the day.

seconds

9 GPS week Week number in GPS Time. Thisfield is related to the GPS weekof the data snapshot used for thecomputations.

weeks

10 Time of week Seconds elapsed since thebeginning of the week. Thisfield is related to the GPS numberof seconds of the data snapshotused for the computations.

seconds

11 GEO PRN GEO from which the SBAScorrections are used (’0’ means allGEOs)

-

12 IPP Latitude Latitude corresponding to theIonospheric Pierce Point (IPP) usedto compute the ionospheric delay.

degrees(-90-90◦)

Page 85: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 65

13 IPP Longitude Longitude corresponding to theIonospheric Pierce Point (IPP) usedto compute the ionospheric delay.

degrees(0-360◦)

14 Interpolation mode Interpolation mode. 0 for squareinterpolation, [1-4] indicatesthe vertex not used in triangleinterpolation.

-

15 IODI vertex 1 Issue Of Data Ionospheric (IODI)for vertex 1.

-

16 Band Number forvertex 1

Band Number for vertex 1.-

17 IGP vertex 1 Ionospheric Grid Point (IGP)Number for vertex 1

-

18 Vertex 1 IGP receptiontime

Time of reception of last bit ofvertex 1 IGP (seconds of day).

seconds

19 Vertex 1 IGP latitude Latitude of the Ionospheric GridPoint (IGP) for vertex 1

degrees(-90-90◦)

20 Vertex 1 IGP longitude Longitude of the Ionospheric GridPoint (IGP) for vertex 1

degrees(0-360◦)

21 Vertex 1 delay Ionosphere delay (raw value fromMT26) for vertex 1.

L1 metres

22 Vertex 1 variance Ionosphere variance (raw valuefrom MT26) for vertex 1.

L1metres2

23 Vertex 1 εiono Degradation term for vertex 1. L1 metres

24 Vertex 1 delayinterpolated

Ionosphere delay after interpolation(if required) for vertex 1.

L1 metres

25 Vertex 1 varianceinterpolated

Ionosphere variance after applyingdegradation and interpolation (ifrequired) for vertex 1.

L1metres2

26 Vertex 1 weight Interpolation weight for vertex 1. -

27 IODI vertex 2 Issue Of Data Ionospheric (IODI)for vertex 2.

-

28 Band Number forvertex 2

Band Number for vertex 2.-

29 IGP vertex 2 Ionospheric Grid Point (IGP)Number for vertex 2

-

30 Vertex 2 IGP receptiontime

Time of reception of last bit ofvertex 2 IGP (seconds of day).

seconds

31 Vertex 2 IGP latitude Latitude of the Ionospheric GridPoint (IGP) for vertex 2

degrees(-90-90◦)

32 Vertex 2 IGP longitude Longitude of the Ionospheric GridPoint (IGP) for vertex 2

degrees(0-360◦)

Page 86: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

66 SBAS Input parameters and output messages

33 Vertex 2 delay Ionosphere delay (raw value fromMT26) for vertex 2.

L1 metres

34 Vertex 2 variance Ionosphere variance (raw valuefrom MT26) for vertex 2.

L1metres2

35 Vertex 2 εiono Degradation term for vertex 2. L1 metres

36 Vertex 2 delayinterpolated

Ionosphere delay after interpolation(if required) for vertex 2.

L1 metres

37 Vertex 2 varianceinterpolated

Ionosphere variance after applyingdegradation and interpolation (ifrequired) for vertex 2.

L1metres2

38 Vertex 2 weight Interpolation weight for vertex 2. -

39 IODI vertex 3 Issue Of Data Ionospheric (IODI)for vertex 3.

-

40 Band Number forvertex 3

Band Number for vertex 3.-

41 IGP vertex 3 Ionospheric Grid Point (IGP)Number for vertex 3

-

42 Vertex 3 IGP receptiontime

Time of reception of last bit ofvertex 3 IGP (seconds of day).

seconds

43 Vertex 3 IGP latitude Latitude of the Ionospheric GridPoint (IGP) for vertex 3

degrees(-90-90◦)

44 Vertex 3 IGP longitude Longitude of the Ionospheric GridPoint (IGP) for vertex 3

degrees(0-360◦)

45 Vertex 3 delay Ionosphere delay (raw value fromMT26) for vertex 3.

L1 metres

46 Vertex 3 variance Ionosphere variance (raw valuefrom MT26) for vertex 3.

L1metres2

47 Vertex 3 εiono Degradation term for vertex 3. L1 metres

48 Vertex 3 delayinterpolated

Ionosphere delay after interpolation(if required) for vertex 3.

L1 metres

49 Vertex 3 varianceinterpolated

Ionosphere variance after applyingdegradation and interpolation (ifrequired) for vertex 3.

L1metres2

50 Vertex 3 weight Interpolation weight for vertex 3. -

51 IODI vertex 4 Issue Of Data Ionospheric (IODI)for vertex 4.

-

52 Band Number forvertex 4

Band Number for vertex 4.-

53 IGP vertex 4 Ionospheric Grid Point (IGP)Number for vertex 4

-

54 Vertex 4 IGP receptiontime

Time of reception of last bit ofvertex 4 IGP (seconds of day).

seconds

Page 87: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 67

55 Vertex 4 IGP latitude Latitude of the Ionospheric GridPoint (IGP) for vertex 4

degrees(-90-90◦)

56 Vertex 4 IGP longitude Longitude of the Ionospheric GridPoint (IGP) for vertex 4

degrees(0-360◦)

57 Vertex 4 delay Ionosphere delay (raw value fromMT26) for vertex 4.

L1 metres

58 Vertex 4 variance Ionosphere variance (raw valuefrom MT26) for vertex 4.

L1metres2

59 Vertex 4 εiono Degradation term for vertex 4. L1 metres

60 Vertex 4 delayinterpolated

Ionosphere delay after interpolation(if required) for vertex 4.

L1 metres

61 Vertex 4 varianceinterpolated

Ionosphere variance after applyingdegradation and interpolation (ifrequired) for vertex 4.

L1metres2

62 Vertex 4 weight Interpolation weight for vertex 4. -

63 Mapping function Value of the mapping function. L1 metres

64 Slant delay Total slant delay. L1 metres

65 Slant sigma Total slant sigma. L1 metres

66 Elevation Elevation angle between thesatellite and the receiver location.

degrees

67 Azimuth Azimuth angle between the satelliteand the receiver location.

degrees

Table A.11: SBASIONO message

NOTE: Vertex 1 is the IGP north east to IPP, vertex 2 is the IGP north westto IPP, vertex 3 is the IGP south west to IPP and vertex 4 is the IGP southeast to IPP.

A.2.5 SBASUNSEL message

SBAS satellite unselection message. When a satellite is discarded due to MOPScriteria (from RTCA-MOPS (2006)), this message details the reason. The list oferror messages in table A.12 is ordered in the same order as the SBAS correctionare computed.

# FIELD DESCRIPTION UNITS1 SBASUNSEL Fixed word indicating the data

stored.-

2 Receiver id Receiver identification. -

3 Mode SBAS processing mode: PA, NPA. -

Page 88: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

68 SBAS Input parameters and output messages

4 GNSS system Satellite constellation (GPS, GAL,GLO or GEO).

-

5 PRN Satellite identifier. -

6 Year Year number (4 digits). years

7 DoY Day of Year (3 digits). days

8 Seconds of day Seconds elapsed since thebeginning of the day.

seconds

9 GPS week Week number in GPS Time. Thisfield is related to the GPS weekof the data snapshot used for thecomputations.

weeks

10 Time of week Seconds elapsed since thebeginning of the week. Thisfield is related to the GPS numberof seconds of the data snapshotused for the computations.

seconds

11 GEO PRN GEO from which the SBAScorrections are used (’0’ means allGEOs)

-

12 Error code Number identifying the reason fordiscarding the satellite.

-

13 Error message Message detailing the reason fordiscarding the satellite.

-

Table A.12: SBASUNSEL message

NOTE: The error code in field 12 is a number which identifies the discardreason with a range from 1 to 45 (useful for parsing purposes). Field 13 will bealways between quotes in order to ease parsing purposes.

A.2.5.1 SBASUNSEL error messages

Here is the list of possible errors in the SBASUNSEL message.

ERROR CODE ERROR MESSAGE1 “No GEO satellites available”

2 “No data for user selected GEO”

3 “Not enough almanac or GEO navigation message todetermine the GEO with highest elevation”

Page 89: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 69

4 “Received alarm message for current GEO at epoch<YYYY DoY SoD!>. Time remaining to finish alarm:<seconds> seconds”

5 “Received 4 or more consecutive messages with errors”

6 “Missed 4 or more consecutive messages”

7 “No PRN mask”

8 “PRN mask timed out”

9 “Satellite is not monitored in any of the PRN maskavailable”

10 “No message type 10 available [PA only]”

11 “Message type 10 timed out [PA only]”

12 “No fast correction data received for current PRN [PAonly]”

13 “Sigma UDRE timed out [PA only]”

14 “Satellite flagged as ’Not monitored’ (UDREI=14)”

15 “Satellite flagged as ’Do not use’ (UDREI=15)”

16 “Satellite has an UDREI value of <value> [PA only]

17 “No fast correction degradation data [PA only]”

18 “Fast correction degradation data timed out [PA only]”

19 “Last PRC received timed out [PA only]”

20 “Only one PRC received. RRC calculation not possible [PAonly]”

21 “RRC timed out (under alarm condition) due to timedifference between PRC used [PA only]”

22 “RRC timed out (under alarm condition) due to excessivePRC propagation in time [PA only]”

23 “RRC timed out due to time difference between PRC used[PA only]”

24 “RRC timed out due to excessive PRC propagation in time[PA only]”

25 “Service message timed out [PA only]”

26 “Not received a full set of service messages with the sameIODS [PA only]”

27 “No clock-ephemeris covariance matrix data for currentsatellite [PA only]”

28 “Clock-ephemeris covariance matrix data timed out [PAonly]”

29 “No navigation data for ranging GEO”

30 “Ranging GEO navigation data timed out”

31 “URA index value of <value> for ranging GEO satellite”

32 “No long term correction data for current satellite [PAonly]”

Page 90: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

70 SBAS Input parameters and output messages

33 “Long-term correction data timed out [PA only]”

34 “No broadcast block with IOD <value> [PA only]”

35 “No broadcast block available for current satellite(regardless of SBAS IOD) [NPA only]”

36 “Could not compute transmission time for current PRNmeasurement [NPA only]”

37 “No ionospheric grid mask [PA only]”

38 “Ionospheric grid mask timed out [PA only]”

39 “IGPs around ionospheric pierce point not found in MOPSgrid [PA only]”

40 “Not enough IGPs available in ionospheric grid mask [PAonly]”

41 “One IGP is set as don’t use [PA only]”

42 “One or more IGPs is set as not monitored or has timedout [PA only]”

43 “Data not available for one or more IGPs [PA only]”

44 “Ionospheric pierce point is outside triangle [PA only]”

45 “External ionosphere model not available”

Table A.13: SBASUNSEL error messages

A.2.6 SBASOUT message

Receiver solution message. This message provides the estimated receiverposition, protection levels and satellites used in solution computation.

# FIELD DESCRIPTION UNITS1 SBASOUT Fixed word indicating the data

stored.-

2 Receiver id Receiver identification. -

3 Mode SBAS processing mode: PA, NPA. -

4 Year Year number (4 digits). years

5 DoY Day of Year (3 digits). days

6 Seconds of day Seconds elapsed since thebeginning of the day.

seconds

7 GPS week Week number in GPS Time. Thisfield is related to the GPS weekof the data snapshot used for thecomputations.

weeks

Page 91: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

A.2. Output messages 71

8 Time of week Seconds elapsed since thebeginning of the week. Thisfield is related to the GPS numberof seconds of the data snapshotused for the computations.

seconds

9 GEO PRN GEO from which the SBAScorrections are used (’0’ means allGEOs)

-

10 ∆N Receiver North difference inrelation to nominal a prioriposition.

metres

11 ∆E Receiver East difference in relationto nominal a priori position.

metres

12 ∆U Receiver Up difference in relation tonominal a priori position.

metres

13 HE Receiver Horizontal Error (HE). metres

14 HPL Receiver Horizontal ProtectionLevel (HPL).

metres

15 VPL Receiver Vertical Protection Level(VPL).

metres

16 Receiver clock offset Offset associated to the receiverclock.

metres

17 Satellites in view Number of satellites in viewsuitable for SBAS.

-

18 Satellites used in filter Number of satellites used in SBASsolution computation.

-

19 List of satellites Satellite list. Each satellite willhave as a first character, a ’+’if it was used in the solutioncomputation, or a ’-’ if it was not.The second character is the systemidentifier (G->GPS, E->Galileo,R->GLONASS, S->GEO). Thenext two characters are the PRNidentifier. The list is sorted,showing first the satellites used inthe computation and at the end theones not used.

-

Table A.14: SBASOUT message

Page 92: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 93: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Acknowledgements

I would like to thank all the members of the gAGE group that have helped mefulfill this project: Dr. Jaume Sanz Subirana, Dr. Jose Miguel Juan Zornoza,Dr. Adria Rovira Garcia, Jesus Romero Sanchez, Yixie Shao and Maria TeresaAlonso.

I would like to thank my family for their support and their continuouspersevererance for making me finish the electronic engineering degree.

This project has been sponsored by the ESA project ”gLAB SW Upgrade forEGNOS Data Processing”, contract No. 4000113054/14/NL/HK.

Page 94: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 95: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Bibliography

Bruyninx, C (2004) The EUREF Permanent Network: a multi-disciplinarynetwork serving surveyors as well as scientists. GeoInformatics 7:32–35

Centre National d’Etudes Spatiales (2016) URL https://cnes.fr/en

ECAC (2016) ECAC Member States. https://www.ecac-ceac.org/

member-states

EUREF (2016) EUREF Permanent Network. URL http://www.epncb.oma.

be/_networkdata/siteinfo4onestation.php?station=VIGO00ESP

European GNSS Agency (GSA) (2016) Galileo constellation status. http:

//www.gsc-europa.eu/system-status/Constellation-Information,accessed: 2016-05-09

European GNSS Agency (GSA) (2015) GNSS market report. Luxembourg,doi: 10.2878/251572, URL http://www.gsa.europa.eu/system/files/

reports/GNSS-Market-Report-2015-issue4_0.pdf

Hernandez-Pajares M, Juan M, Sanz J (2002) Egnos tutorial. http://gage14.upc.es/TEACHING_MATERIAL/SLIDES/EGNOS_tutorial_gAGE.pdf

Ibanez, D (2014) Implementation of GNSS Ionospheric models in gLAB. URLhttp://upcommons.upc.edu/handle/2099.1/24770

ICAO (2006) Standards and Recommended Practices, Annex 10, Volume 1Radio Navigation Aids

Information and Analysis Centre (IAC) (2016) Glonass constellation status.https://www.glonass-iac.ru/en/GLONASS/, accessed: 2016-05-09

International GNSS Service (IGS) (2016) Beidou constellation status. https://igscb.jpl.nasa.gov/projects/mgex/Status_BDS.htm, accessed: 2016-05-09

Page 96: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

76 BIBLIOGRAPHY

International GNSS Service Products (2014) http://www.igs.org/

products/data

IS-GPS-200 (2010) GPS Interface Specification IS-GPS-200. Revision E.,http://www.gps.gov/technical/icwg/is-gps-200e.pdf

Juan M, Sanz J, Gonzalez-Casado G, Rovira-Garcia A, Ibanez Segura D,Orus-Perez R, Prieto-Cerdeira R, Schlueter S (2014) Accurate referenceionospheric model for testing GNSS ionospheric correction in EGNOS andGalileo. In: Proceedings of the 7th ESA Workshop on Satellite NavigationTechnologies: Era of Galileo IOV (NAVITEC 2014), ESA/ESTEC, Noordwijk,The Netherlands, URL http://gage6.upc.es/gAGE_WEB/papers/2014/

73415_Juan.pdf

Kalman, Rudolph Emil (1960) A New Approach to Linear Filtering andPrediction Problems. Transactions of the ASME–Journal of Basic Engineering82(Series D):35–45

Navipedia (2011a) EGNOS General Introduction. http://www.navipedia.

net/index.php/EGNOS_General_Introduction

Navipedia (2011b) MSAS General Introduction. http://www.navipedia.net/index.php/MSAS_General_Introduction

Navipedia (2011c) WAAS General Introduction. http://www.navipedia.net/index.php/WAAS_General_Introduction

Navipedia (2016) SBAS Fundamentals. URL http://www.navipedia.net/

index.php/SBAS_Fundamentals

NovAtel (2013) Spaced based augmentation systems (sbas). http://www.

novatel.com/products/novatel-correct-with-sbas-and-dgps/,accessed: 2016-05-09

OXTS (2014) More SBAS regions added forusers in india and russia. http://www.oxts.com/

more-sbas-regions-added-for-users-in-india-and-russia/,accessed: 2016-05-09

Rovira-Garcia A, Juan J, Sanz J, Gonzalez-Casado G, Ibanez Segura D (2015a) AMethodology to Assess Ionospheric Models for GNSS. In: Proceedings of theEuropean Geosciences Union General Assembly 2015 Geophysical ResearchAbstracts Vol. 17, Vienna, Austria, URL http://meetingorganizer.

copernicus.org/EGU2015/EGU2015-1015.pdf

Rovira-Garcia A, Juan J, Sanz J, Gonzalez-Casado G, Ibanez SeguraD (2015b) Accuracy of Ionospheric Models used in GNSS andSBAS: Methodology and Analysis. Journal of Geodesy 90(3):229–240,

Page 97: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

BIBLIOGRAPHY 77

doi: {10.1007/s00190-015-0868-3}, URL http://dx.doi.org/10.1007/

s00190-015-0868-3

Rovira-Garcia A, Juan J, Sanz J, Gonzalez-Casado G, Ibanez Segura D(2015c) Assessment of Ionospheric Models Tailored for Navigation. In: SBASIonospheric Working Group Meeting 22, Trieste, Italy

Rovira-Garcia A, Juan M, Sanz J, Gonzalez-Casado G, Ibanez Segura D,Romero-Sanchez (2015d) Assessment of Ionospheric Models for GNSS Duringa Year of Solar Maximum. In: Proceedings of ION GNSS+ 2015, Tampa,Florida (USA), pp 3833–3840, URL http://www.ion.org/publications/

abstract.cfm?jp=p&articleID=13088

RTCA-MOPS (2001) Minimum Operational Performance Standards forGlobal Positioning System/Wide Area Augmentation System AirborneEquipment.RTCA Document 229-C

RTCA-MOPS (2006) Minimum Operational Performance Standards forGlobal Positioning System/Wide Area Augmentation System AirborneEquipment.RTCA Document 229-D

Sanz J, Juan J, Hernandez-Pajares M (2013) GNSS Data Processing, Vol. I:Fundamentals and Algorithms. ESA Communications, ESTEC. TM-23/1.,Noordwijk, the Netherlands

SC-159 RF (2005) GNSS-based Precision Approach Local Area AugmentationSystem (LAAS) Signal-in-space Interface Control Document (ICD). RTCA,URL https://books.google.es/books?id=dQWbngEACAAJ

Todd Walter (1999) WAAS MOPS: Practical Examples. http://waas.

stanford.edu/mops/mops_ex.pdf

USA Navigation Center (2016) Gps constellation status. http://www.navcen.uscg.gov/?Do=constellationstatus, accessed: 2016-05-09

Ventura-Traveset, J, Flament D (2006) EGNOS: The European GeostationaryNavigation Overlay System: A Cornerstone of Galileo. ESA PublicationsDivision, ESTEC. Series ESA SP 1303., Noordwijk, the Netherlands

Vinh L, Quang PX, Garcia-Rigo A, Rovira-Garcia A, Ibanez Segura D (2013)Experiments on the Ionospheric Models in GNSS. In: Proceedings of 20thAsia-Pacific Regional Space Agency Forum, Hanoi, Vietnam, vol 113

Page 98: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final
Page 99: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

Index

Data Processing Core (DPC), 10

Graphical User Interface (GUI), 7,43

GNSS-Lab Tool suite (gLAB)positioning example, 11

GBAS, 19

GNSS, 1

BeiDou, 2

GLONASS, 1

GPS, 1

Receiver, 30

Galileo, 1, 43

SBAS, 17, 43

Architecture, 21

Corrections, 24

Data, 19

Integrity, 22

Alarm Limit, 22

Protection Level, 22, 23

Modes, 22

Operation modes, 23

HMI, 23

MI, 23

Normal operation, 23

System unavailable, 23

Requirements, 17

Requirements Values, 22

Systems, 20

EGNOS, 20, 43

GAGAN, 20

MSAS, 20

SDCM, 20

WAAS, 20SBAS Figures of Merit, 37SBAS Input parameters and output

messages, 49SBAS description, 17SBAS plots

HE, 37HPL, 37NEU, 37Stanford, 37Stanford-ESA, 37VE, 37VPL, 37

gLAB applications and future work,41

gLAB description, 5gLAB usage examples with SBAS,

29

Acronyms list, XVIIApplications, 41

Command line examples, 31

Data gathering, 29

Future work, 43

Input parameters, 27, 49Filter parameters, 28, 54Help parameters, 27, 49Input parameters, 27, 49Model parameters, 27, 51Output parameters, 28, 54

Page 100: gLAB upgrade with EGNOS data processing - upcommons.upc.edu Upgrade... · gLAB upgrade with EGNOS data processing Author: Deimos Ib anez~ Segura ... El objetivo de este Proyecto Final

80 INDEX

Preprocessing parameters, 27,50

Verbose parameters, 28, 55

Introduction, 1

Architecture, 2

Segments, 2

Main gLAB features, 6

New Input parameters and outputmessages in gLAB, 27

Output messages, 28, 57

SBASCORR message, 28, 58

SBASIONO message, 28, 64

SBASOUT message, 28, 70

SBASUNSEL message, 28, 67

SBASUNSEL error messages,68

SBASVAR message, 28, 62USERADDEDERROR message,

28, 57

Publications using gLAB, 45

Signal, 3Components, 3

Carrier, 3Frequencies, 3Navigation data, 3Pseudo-Random Noise, 3Ranging code, 3

SystemsEGNOS

Receiver, 30