Topics · 2016-04-13 · RNAV APCH, APV-SBAS 30.3.2016 SIO lennonopettajien kertauskoulutustilaisuus Tommi Antila SUOMEN ILMAILUOPISTO FINNISH AVIATION ACADEMY 1. Introduction 2

RNAV APCH, APV-SBAS

30.3.2016SIO lennonopettajien kertauskoulutustilaisuusTommi Antila

SUOMEN ILMAILUOPISTOFINNISH AVIATION ACADEMY

1. Introduction2. GNSS core systems and augmentation systems3. PBN RNAV appr specifications4. RNAV avionics, RNP APCH receivers5. RNP APCH, regulation, requirements6. EASA AMC 20-28 LPV Operating procedures

Topics

2

Radio navigation infrastructure in Finland

Introduction3

• Navigation and surveillance strategy (Trafi)

• From conventional radio navigation tosatnav and rnav– Current VOR availability

• Issues:– Training possibilities– Contingency procedures– New avionics, procedures, approvals

PBN (EUR) navigation applications

4

RNAV 5 = B-RNAV, RNAV 1 =~ P-RNAV

Introduction

PBN navigation specifications

Introduction5

PBN applications in Europe:En-route: RNAV 5 (=B-RNAV)Terminal: RNAV 1 (=~P-RNAV)NPA and APV appr: RNP APCH

Performance based navigation – fundamentals

Introduction6

• PBN requires the use of an on-board rnavsystem

• PBN creates requirements for airworthinesscertification and operational approval to usernav systems in airspace implementations

• The rnav system’s functionality as well as itsnavigation accuracy in the navaid infrastructureenvironment of the subject airspace mustconform to the requirements stipulated in therelevant icao navigation specification

Area navigation – main differences compared toconventional radio navigation

Introduction7

• Flexibility of routing and procedure design

• Guidance is not based on fixed radio beams and signals:– Position and guidance is calculated with computers, they

are not based on measured guidance signals– Integrity challenges– Databases

• Flexibility:– May create complexity– Operational procedures– Situational awareness

GNSS

Global Navigation Satellite SystemCore systems and augmentation

GNSS = Global Navigation Satellite System

Core system used in aviation: GPS = Global positioning system

GNSS augmentation systems:• Improve accuracy and integrity (flag warning)

SBAS, Space Based Augmentation Systems:• EGNOS = European Geostationary Navigation Overlay System

(EU)• WAAS = Wide Area Augmentation System (US), MSAS (JP) etc.

GBAS, Ground Based Augmentation Systems:• LAAS = Local Area Augmentation System (US)

GNSS – core systems and augmentation

9 Global Navigation Satellite System

GPS, space segment


Six orbital planes

4 satellites / plane

28-30 satellitestypical (spares)

Orbit time 12 h

Orbit height 20 200km above ground

GPS, control segment


MCS MasterControl StationSchriever airbase

Monitors orbits,clocks and NAV-messages

Re-calculatesnew orbitparameters(ephemerides)

Uploads NAV-messages

GPS satellite


4 ’atomic clocks’

Transmits NAV-message 50 bit/s

Satellite signals arespread with pseudorandom noise (PRN)codes 1.023 Mbit/s

GPS satellite


PRN codes are used for:

Separating satellite signals fromeach satellite in the receiver

Makes accurate propagationtime measurements possible,like DME range gate

Codes are numbered, e.g.PRN06 (pseudo random noisecode)

GPS, pseudorange ranging


Received satelliteC/A code signal

Same codegenerated in thereceiver

Correlationproduces apseudorange anddecodes the NAV-message

GPS receiver


When powered up,microprocessorsoftware will setappropriate PRN codesto the channels

Channels lock andbegin measuringpseudoranges andreceiving NAV-messages

Position can becalculated based onthese – in addition: timetransfer

Rf-parts,analog todigital

correlation,’channels’

pseudoranges,nav-msg data

microprocessor

clock osc.

GPS navigation data message


GPS nav message content


subframe 1 : flags, GPS-week, nav-message age,satellite status, clock correction parameters

subframe 2 + 3 : exact orbital parameters for thissatellite

subframe 4 : almanac and status for satellites 25-32,ionosphere model, UTC-parameters

subframe 5 : almanac and status for satellites 1-25almanac = ’bus schedule’, approximate orbital data for the wholeconstellation – helps receiver locking

GPS accuracy


Source segment error, aprx [m]

Atomic clocks, NAV-msg space 2Orbit inaccuracies space 1

Orbit calculation control 1

Ionosphere model propagation 5-10Troposphere model propagation 2Multipath propagation 1

Receiver errors user 1

System accuracy, horizontal all 10-14

Note: GPS accuracy changes as a function of time and place

• Problems:

– Accuracy is not good enough especially for verticalguidance during approach (propagation errors)

– Integrity:• GPS monitoring is complicated, handled by the control

segment• GPS nav-message transmission is slow, the critical data

blocks are updated once per 30 seconds

Using GPS for aviation


Differential GPS - DGPS


Monitor station:

- has a fixed GPSantenna, position isknown with highaccuracy

- can calculate thedifference between realvs. measured rangesto satellites ->pseudorangecorrections to users

- can verify GPS statusand send integritymessages to users

SBASSpace Based Augmentation SystemEGNOS

EGNOS – the European SBAS system

European Geostationary Navigation Overlay Service

Includes a Safety-of-Life service with high integrity, suitable for aviationneeds

• Differential corrections

• Integrity messages

System comprises of:

RIMS, Ranging and Integrity Monitoring Stations

MCC, Mission Control Centres

NLES, Navigation Land Earth Stations (links to GEO-satellites)

GEO, Geostationary satellitesEGNOS - the European SBAS system22

EGNOS

EGNOS - the European SBAS system23

EGNOS RIMS stations


EGNOS

• European Geostationary Navigation Overlay Service

• Differential correction data messages -> improve accuracy

• Integrity data messages -> improve integrity (flag warnings)

• Ranging service -> use as a normal GPS satellite (disabled)

• EGNOS signal is quite similar to a GPS signal, so there is no need for aseparate receiver for EGNOS signals

• In aviation applications users can fly APV (LPV) approaches down to250ft / 200ft minima

https://www.youtube.com/watch?v=ojO8TAitQoc


EGNOS availability – horizontal and vertical protection limits


PBN navigation specificationsApproach

Factors effecting navigation performance:

• Navigation systems and avionics -> position uncertainty

• Flight technical error components– Raw data, F/D manual flight, F/D+A/P

• Database integrity (Path Definition error components)

Navigation performance

28 PBN navigation specifications

• Key points for safety:

• You have adequate navigation performance – and you know itis adequate or, in abnormal cases:

• You do not have adequate navigation performance – and youknow it is not adequate

• The biggest risk associated with navigation is HMI -Hazardously Misleading Information: you have a fault andthere is no warning! Propability for this situation must be verylow.

Navigation performance


• continuous indication of aircraft position relative to track tobe displayed to the pilot flying on a navigation displaysituated in his primary field of view

• display of distance and bearing to the active (To) waypoint

• display of ground speed or time to the active (To) waypoint;

• navigation data storage function

• appropriate failure indication of the RNAV or RNP system,including the sensors

RNAV and RNP, common features

PBN navigation specifications30

• On-board performance monitoring and alerting is themain element that determines whether the navigationsystem complies with

navigation performance

10–5 integrity confidence level requirement

• On-board performance monitoring and alerting is arequirement in RNP area navigation specifications

RNP: main difference

PBN navigation specifications31

Crosstrack or.. Angular deviations

RNAV guidance displays


PBN navigation specifications, approach

RNP APCH specifications33

New approach type: APV

Due to advances in satellite navigation and areanavigation we now have new approaches:

Approach procedure with vertical guidance (APV)

• Lateral and vertical guidance

• Good navigation accuracy

• Minimum: DA/H

ICAO has defined APV-approaches as acompletely new approach type in addition to NPAand PA approaches


APV-instrument approach procedures

There are two sub-types of APV:

APV-BARO• Lateral navigation: Basic GNSS (as in non-precision approach)• Vertical guidance: barometric glide path

• Temperature compensated systems, or• Outside air temperature limitation

• Minimum (and OCA) marked as: ’LNAV/VNAV’

APV-SBAS• Lateral and vertical navigation with space based augmentation (in

Europe: EGNOS)• Minimum (and OCA) marked as: ’LPV’


PBN RNP APCH specification

36 RNP APCH specifications

RNAV non-precision approach• Lateral navigation: Basic GNSS• Accuracy in final approach segment ±0,3NM• RAIM required, RAIM prediction required

APV-BARO• Lateral navigation: Basic GNSS• Vertical guidance: barometric glide path• Accuracy in FAS ±0,3NM / ±75ft• RAIM required, RAIM prediction required

APV-SBAS• Lateral and vertical navigation with space based augmentation• EGNOS ’channel’ used for procedure identification• Accuracy in final approach almost like ILS, vertical alarm limit 50m• Integrity assured with SBAS, RAIM is not needed but SBAS usability

check is required – RAIM FDE is as a backup


• Three initial approach fixes (IAF) ofwhich any one can be used for straightin approach, however:• Maximum intercept angle is 110°• At IAF/IF there is a possibility for

holding (Automatic sequencing off)• Last fix for direct entry by ATC is

the intermediate fix (IF) within ±45º

• There is no entry to the FAF from anoffset angle, aircraft has to beestablished before FAF (radar vectorsto 2 NM before FAF)

• 2 NM before final approach fix (FAF)the receiver makes last RAIM signalevaluation and if it is ok, status changesto approach (Garmin ’GPS LNAV’) ->display ramps down to ±0.3NM

• In DA42NG, en-route CDI maximumdeflection is ±2NM

PANS OPS changes in process:• Naming of the procedures

PBN RNP APCH charts


RNAV (GNSS) NPA / APV-baro approach DA42NG


• DA42NG G1000 avionics can use linear crosstrack or angularguidance in the final approach for LNAV (or LNAV+V)

RNAV (GNSS) APV-BARO approach


• Lateral guidance is identical to the non-precisionapproach

• Vertical guidance based on barometric glidepath– Based on the published threshold crossing height (same

as reference datum height) and VPA, vertical path angle– Temperature compensated vs. non-compensated systems

• Minimum temperature limitation

• APV-BARO procedures can be flown with SBASavionics, if the database is coded so that this is allowed– In Finland currently not allowed



• Glide path built based on the published thresholdcrossing height (same as reference datum height) andVPA, vertical path angle



• FSD = Full Scale Deflection• G1000 annunciation: ’GPS L/VNAV’• Guidance needle and GS triangle in magenta color• DA42NG: only when SBAS is available and procedure allows

Performance Based NavigationPBN navigation specificationsRNP APCH – APV-SBAS approach

RNAV (GNSS) APV-SBAS approach


• Lateral and vertical guidance is based on SBAS, in EuropeEGNOS

• In US APV-SBAS is simply called ’LPV’, LocalizerPerformance with Vertical guidance

• High accuracy, high integrity

• ILS look-alike, sensitivities are almost exactly like in ILS

• Requires precise Final Approach Segment (FAS) data block,which is programmed to the data base– FAS block is protected with a CRC (cyclic redundancy check)

parameter, which is verified by the receiver



• Final approach is constructed mathematically in thereceiver using FAS data block parameters



Approach parameters in FAS data block:• Operation Type ( i.e APV )• FPAP ( Flight Path Alignment Point)• LTP ( Lat/ Lon WGS84)• LTP ellipsoidal height• GP Angle (VPA)• GP course width• HAL (Horizontal Alert Limit)• VAL (Vertical Alert Limit)• Others



RNAV (GNSS) APV-SBAS approach DA42NG




G1000 annunciation: ’GPS LPV’

Guidance needle and GS triangle in magenta color

Can be used only when SBAS, i.e. EGNOS in Europe is available

APV SBAS: Video

• SBAS: how it works recap:

• In the US, APV-approaches arecalled LPV approaches

• In the US, WAAS is the SBASaugmentation system likeEGNOS is in Europe

Bombardier Global Express videohttp://www.youtube.com/watch?v=oxWm81YHPlg


RNAV (GNSS) approach features


Approachprocedure

Lateralguidance

Verticalguidance

Integritybased on

Preflightchecks

LNAVNPA Basic GNSS n/a RAIM RAIM

Prediction

LNAV/VNAVAPV-BARO Basic GNSS Baro VNAV

(or SBAS) RAIM RAIMPrediction

LPVAPV-SBAS GPS SBAS GPS SBAS SBAS

SBASAvailability

check

Performance Based NavigationRNAV avionicsRNP APCH receivers

DO-229() SBAS receiver classification

RNP APCH SBAS avionics53

• Beta– Sensor Only. Does Not Have Navigation Function– Generates Position, Velocity, Time, with Integrity– Typically Provides PVT To An FMS Which Provides Navigation

Function• Gamma

– Typical Panel Mount Receiver– Beta Sensor Plus Navigation Function With Procedure Database

And User Controls• Delta

– Beta Sensor With Navigation Function That Provides Deviationsto A Final Approach Segment Only

– Functions Like ILS (e.g. Does Not Support En Route Navigation)

SBAS receiver Class Beta


SBAS receiver Class Gamma


SBAS receiver Class Delta


Requirements for SBAS receivers


RTCA/DO-229D (Radio Technical Commission for Aeronautics)• Minimum Operational Performance Standards for GPS/WAAS

Airborne Equipment

RTCA/DO-160E• Environmental Conditions and test Procedures for Airborne

Equipment

RTCA/DO-310• Minimum Operational Performance Standards for GNSS Airborne

Active Antenna Equipment for the L1 Frequency Band.

RTCA/DO-254• Design Assurance Guidance for Airborne Electronic Hardware


RTCA/DO-178B• Software Considerations in Airborne Systems and Equipment

Certification

RTCA Document DO-160 versions D, E, and F• Environmental Conditions and Test Procedures for Airborne

Equipment

TSO-C145-b/c• Minimum Performance standards for Airborne Navigation Sensors,

using the Global Positioning System (GPS) Augmented by the WideArea Augmentation System (WAAS)

TSO-C146c• Minimum performance standards for Class Gamma or Class Delta

equipment, using GPS augmented by WAAS

Requirements for SBAS receivers

DA42NG G1000 SBAS avionics


DA42NG G1000 SBAS avionics


The GIA 63(W) SBAS characteristics• A 12+3 channel parallel GPS / WAAS receiver that

simultaneously tracks and uses up to 12 GPS and 3 WAASsatellites

• Horizontal accuracy 1,25m (RMS)• Vertical accuracy 2,00m (RMS)• Time-to-first-fix 1:45• Update frequency: 5 updates / sec• Fulfills sensor requirements for:

– TSO-C145A– AMC 20-4 (B-RNAV)– TGL 10 (P-RNAV)– RTCA/DO-229C Class Beta 3 LNAV, LNAV/VNAV, LPV approach

Performance Based NavigationRNP APCH - LPV approachRegulation and other information

RNP APCH requirements

RNP APCH LPV Regulation62

RNP APCH, LNAV and LNAV/VNAV requirements


• ICAO Doc 9613 PBN Manual VOL II Part C Ch 5: RNP APCH

• Airworthiness– EASA AMC 20-27a– FAA AC 20-130A, AC 20-138A, AC 20-129, (replaced by AC 20-

138B and C)– ETSO/TSO C129a, ETSO/TSO C145a and C146

• Operations– EASA AMC 20-27a– FAA AC 90-105

RNP APCH, LPV requirements


• ICAO Doc 9613 PBN Manual VOL II Part C Ch5: RNP APCH

• Airworthiness– EASA AMC 20-28– FAA and European regulation for equipment qualification

standard based on DO 229():– E/TSO C146() for « stand-alone » receiver– E/TSO C145() for SBAS sensor– FAA AC 20-138A/ 138C

• Operational– EASA AMC 20-28– FAA AC OPS: AC 90-107 etc.

RNP APCH, LPV requirements


• Regulation and approval related materials in the web:– http://www.egnos-portal.eu/sites/default/files/EGNOS-How-

to-Obtain-RNP-APCH-(LPV)-Operational-Approval-in-Europe.pdf

– http://www.gsa.europa.eu/sites/default/files/LPV_Implementation_Guidelines_Airports_Operators_0.pdf

• RNP-APCH ICAO seminar material in the web:– http://www.icao.int/WACAF/Documents/Meetings/2014/OP

S-Approval/15%20October%202014/08%20-%20RNP%20APCH.pdf

Finavia AIC A documents:• https://ais.fi/ais/aica/A/A2013/EF_CIRC_2013_A_014_en.pdf• https://ais.fi/ais/aica/A/A2013/EF_CIRC_2013_A_015_en.pdf• EGNOS NOTAMs for EFJO

EGNOS service status (ESSP):• https://egnos-user-support.essp-sas.eu/egnos_ops/index.php

LPV, APV SBAS information

66 RNP APCH LPV Regulation

LPV, APV SBAS in flight plans


• https://ais.fi/files/finavia2/FPL%20-ohjeet/FPL_tayttoohje_suomeksi.pdf

• Field 10, equipment– LPV, APV SBAS capability, add letter ’B’– APV SBAS is a part of PBN, so add also ’R’

• Field 18, remarks– NAV/SBAS– PBN/S1 (for RNP APCH NPA)

• These are not fully logical due to FPL developmentprocess.. (there is no ‘S3’ for APV-SBAS)

LPV, APV SBAS in flight plans


Performance Based NavigationRNP APCH - LPV approachOperational considerationsAccording to EASA AMC 20 - 28

LPV APCH operational procedures – pre flight

LPV operational procedures70

• Nav data valid and current• Verify charts vs. database vs. display on CDU• Verify procedure is in use, NOTAMs etc• Verify LPV minima in accordance with the promulgated OCA(H) and

the operational requirement (e.g. EU-OPS 1.430) the DecisionAltitude/Height (DA(H))

Note: For LPV approach operations, the Flight Crew selects the desiredapproach procedure using its name or the SBAS channel number andthe on board system automatically extracts the high-integrity procedureand associated alert limits (VAL, HAL). This information is protectedfrom data corruption by a cyclic redundancy check (CRC) determinedduring the procedure design.

(Note: SBAS channels are between 40000..99999)



The Flight Crew should ensure sufficient means are available tonavigate and land at the destination or at an alternate aerodromein the case of loss of the capability to perform RNAV(GNSS)approaches to the published minima.

Operators and Flight-Crews must take account of any NOTAMs(including SBAS NOTAMs) or operator briefing material thatcould adversely affect the aircraft system operation, or theavailability or suitability of the procedures at the airport oflanding, or any alternate airport.

AIC A14 / 2013 3.4 – 3.5, AIC A15 / 2013 ch 7https://egnos-user-support.essp-sas.eu/new_egnos_ops/



If the missed approach procedure is based on conventionalmeans (e.g. VOR, DME) the appropriate airborne equipmentrequired to fly this procedure must be available and serviceableon board the aircraft. The associated ground-based navigationaids must also be operational.

If the missed approach procedure is based on RNAV (noconventional or dead reckoning missed approach available) theappropriate airborne equipment required to fly this proceduremust be available and serviceable on board the aircraft.

Any MEL restriction must be observed.

LPV APCH – Prior to Commencing the Procedure


the Flight Crew must verify the correctness of the loaded procedure bycomparison with the appropriate approach charts. This check mustinclude:

• The waypoint sequence;

• Reasonableness of the tracks and distances of the approach legs,and the accuracy of the inbound course and mileage of the finalapproach segment.

• Note: As a minimum, this check could be a simple inspection of asuitable map display.

• The vertical path angle where the system permits.

LPV APCH – Prior to Commencing the Procedure


In complying with ATC instructions, the Flight Crew should be aware ofthe implications for the navigation system in particular:

The manual entry of coordinates into the navigation system by theFlight Crew for operation within the terminal area is not permitted;

‘Direct to’ clearances may be accepted to the Intermediate Fix (IF)provided that the resulting track change at the IF does not exceed 45º.Note: Direct to clearance to FAP is not acceptable.

The approach system provides the capability for the Flight Crew tointercept the Final Approach track well before the FAP (Vector To Final(VTF) function or equivalent.

LPV APCH – During the Procedure


• The crew must check that the GNSS approach modeindicates LPV (or an equivalent annunciation) prior topassing the FAP

The final approach segment should be intercepted beforethe The appropriate displays should be selected so that thefollowing information can be monitored:

• aircraft position relative to the lateral path;• aircraft position relative to the vertical path;• absence of LOI (Loss Of Integrity) alert.



• The crew should respect all published altitude and speedconstraints.

• The Flight Crew shall maintain the aircraft within ⅓ thefull scale deflection for the lateral deviation and within ½the full scale deflection for the vertical deviation.

• Prior to sequencing the FAP, the procedure must bediscontinued or may be continued to LNAV minima whensupported by the system if there is:– loss of integrity is indicated by a warning annunciator



After sequencing the FAP, the procedure must be discontinued, unlessthe Flight Crew have in sight the visual references required to continuethe approach if there is:• loss of integrity is indicated by a warning annunciator;• loss of vertical guidance is indicated (even if lateral guidance is

displayed);• lateral or vertical deviation are excessive and cannot be timely

corrected.

The missed approach must be flown in accordance with the publishedprocedure (e.g. conventional or RNAV).

Note: Alternatively, when the aircraft is still above 1 000 ft. AGL, thepilot may decide to continue the approach to LNAV minima whensupported by the system.

LPV APCH – Abnormal Procedures


Abnormal procedures to address Cautions and Warnings resulting fromthe following conditions should be developed:

• Failure of the navigation system components, including thoseaffecting flight technical errors (e.g. failures of the flight director orautopilot).

• Loss of integrity annunciation.

• Warning flag or equivalent indicator on the lateral and/or verticalnavigation display.

• Degradation of the GNSS approach mode during a LPV approachprocedure (e.g. downgrade from LPV to LNAV).

LPV APCH – Abnormal Procedures


• In case of a complete RNAV guidance loss during theapproach, the crew must follow the operator definedcontingency procedure.

• In the event of communications failure, the Flight Crewshould continue with the procedure in accordance withpublished lost communication procedures.

• The Flight Crew should notify ATC of any problem withthe navigation system that results in the loss of theapproach capability.

LPV APCH – Reporting


Occurrence Reports (see EU-OPS 1.420):

a) Significant navigation errors attributed to incorrect dataor a database coding error.

b) Unexpected deviations in lateral/vertical flight path notcaused by pilot input or erroneous operation of equipment.

c) Significant misleading information without a failurewarning.