What are the issues with Multi-GNSS Enabling the National Positioning

Infrastructure?

John Dawson and Gary JohnstonEarth Monitoring and Hazards Group

Quick Recap on Australia’s NPI Plan

A national positioning capability is a key component of Australia’s future economy

Hence Australian Federal Government interest

Quick Recap on Australia’s NPI Plan

Australian government developed a National Positioning Infrastructure (NPI) Plan

Led by Geoscience Australia

Whole-of-Government approach

Recognises the importance of multi-GNSS Mitigates total reliance on GPS Anticipates improved

positioning capabilities through access to more GNSS signals/satellites

Building Australia’s NPI

The three ‘easy’ steps towards building an NPI

National coordination is hard

But the move to multi-GNSS introduces additional challenges

History of Multi-GNSS at Geoscience Australia

Contributing GPS data to the IGS since its inception 1993

Since 2000, Contributing GLONASS data to the IGS -- International GLONASS Experiment

Tracking Galilieo Giove since 2010 (Stromlo, Canberra) and 2011 (Davis, Antarctica) and contribution to the COoperative Network for GIOVE Observation (CONGO)

History of Multi-GNSS at Geoscience Australia

Since 2010, progressively upgrading the national (ARGN+AuScope) network to GPS+GLONASS+others

Since 2010, hosting a QZSS master control station at Mount Stromlo

In 2013, regional multi-GNSS data sharing agreement with JAXAQZSS Monitor Station – Mount Stromlo Canberra

History of Multi-GNSS at Geoscience Australia

Deploying 10 Multi-GNSS Septentrio receivers in 2013-14

CRCSI, Curtin University ionospheric scintillation experiments

Ongoing laser tracking of retro-reflector equipped GPS, GLONASS, COMPASS, Galileo, QZSS satellites

National/Regional Multi-GNSS Tracking – July 2013

Upgrading our network is a multi-year project

Satellite Laser Ranging (SLR)

SLR, Mount Stromlo, Canberra

GNSS (cm-level) orbits can be validated using SLR

SLR observations of GNSS have made important contribution to satellite force modelling

Independent orbit accuracy assessment

Satellite Laser Ranging (SLR)

International Laser Ranging Service (ILRS) tracking priorities as of 1 July 2013

GPS: gps36

QZSS: qzs1

COMPASS: compassm3, compassi3, compassi5, compassg1

GLONASS: glonass129, glonass130, glonass102, glonass109, glonass110

Galileo: galileo104, galileo103, galileo101, galileo102, giovea

Challenge: additional tracking of GNSS using the same SLR resources

Network Operations

UNAVCO TEQC software

software developed and supported at UNAVCO for “translation, editing, quality check” of GNSS data

Used extensively in the IGS community

TEQC built into many internal Geoscience Australia data management and quality assurance processes

TEQC is limited to RINEX 2.x and will not be upgraded to RINEX 3

RINEX 2.x doesn’t support the complexities of multi-GNSS

Re-engineering GA’s data management and quality assurance processes while maintaining normal operations is not a trivial task

Communications Issues

More signals and data

Emergence of supported multi-GNSS formats has been slow

Long-term (data limited) contracts

Often share links with other Geoscience Australia projects to keep costs lower

Australian Tsunami Warning System (ATWS)

Carefully manage communication saturation

Nauru VSAT

Norseman Next-g

Global Reference Frame IssuesAntenna Change

1, 5, 15 mm (ENU)

IGS Reference Frame Core Stations

GNSS Antenna Calibrations

Antenna hardware (elements and preamplifiers) cause phase advance and delay

Phase advance and delay changes cause range bias and consequently impact position determination

Antenna type/model and individual antenna dependent

GNSS Antenna Calibrations

Current capability based around L1 and L2 on GPS + all GLONASS

New antennas

New signals and frequencies present challenges

No L5 GPS

Legal Traceability of GPS in Australia

Legal Issues of using GPS in Australia

What about the other GNSS?

Challenges: Many network operators

Standardisation

Coordinates – National Reg 13 Campaign

Data access policies

Data management

Challenges: International Engagement

• National security implications• Many stakeholders to manage• Different objectives (and challenge of communication)

Multi-GNSS Analysis

No Australian ‘operational’ sovereign capability to process GNSS

No communications infrastructure to deliver precise corrections – any where in Australia and its maritime jurisdictions

A multi-GNSS National Positioning Infrastructure (NPI)

New analysis approaches

Integrating and managing GNSS networks

Working across government and private sectors Expectation of high reliability

Hardware and Software components

High user expectations

Developing new models for sustainability

New and challenging use cases

International coordination