# Presentation: 829585

## Carrier Phased Based Positioning in Australia and in Queensland

- Matt Higgins
- Principal Survey Advisor,
- Department of Natural Resources, Mines and Water
- Chair Commission 5 on Positioning and Measurement,
- International Federation of Surveyors (FIG)

## Outline of the Presentation

- Quick Overview of GNSS in Queensland – by way of Welcome!
- Pseudo Range vs Carrier Phased Based GNSS
- Continuously Operating Reference Stations (CORS) in Australia
- Services for Post processing and Real-Time
- Expanding User Base for Centimetre Accuracy
- A look into the future...

## GNSS in Queensland

- GNSS has long been recognised as an ideal technology for a large, sparsely populated land;
- NRMW has over 20 years experience in GNSS, eg first GPS Surveys in 1985;
- Providing cutting edge GNSS infrastructure - SunPOZ;
- Strong R&D Track Record and Capabilities;
- World class GNSS companies in South East Queensland;
- Currently developing a strategy for Next Generation GNSS in Queensland in line with Queensland Government’s *Smart State *Policy

## The “Pseudo-range”

***Difference between what it should hear and what it does hear is the time delay (5 units in diagram)***
***Range Distance = Time Delay * Speed of Light***
***Not the true range; part of the time delay is due to Receiver Clock Offset ~ hence “pseudo-range”***

## “Carrier Phase” Measurement

***Distance from the satellite to the user’s antenna can also be expressed in terms of the number of wavelengths of the underlying signal carrying the codes.***

***Wavelength of GPS L1 carrier = 19 centimetres;***
***Fractional part (“phase”) of a given wavelength, can be ******measured to 1/100 of a wavelength ~ resolution of 2mm;***
***Enables position relative to a known point with centimetre accuracy;***
***Dual frequency measurements most reliable but accessing L2 carrier signal has required expensive receivers – Will full L2C signal availability change that?***

## Current Techniques for Centimetre Positioning with GPS

***Process 2 datasets in PC for Centimetre accuracy***

***Current Techniques for Centimetre Positioning with GPS***

## Continuously Operating Reference Stations (CORS) - Next Logical Step 

- Australian Regional GNSS Network
- Geoscience Australia (National and International obligations);
- Supporting Post-Processed Carrier Phase based positioning;
- AUSPOS – Online Processing Service.
- CORS Networks in Australian States and Territories
- Government owned networks in Victoria, Queensland, New South Wales and Northern Territory
- Private Sector Network in West Australia
- Supporting Post-Processed Carrier Phase based positioning;
- Delivering Real-Time corrections for Carrier Phase based positioning;
- Not full national coverage for centimetre accuracy.
- Nationwide Commercial Services from Omnistar and Starfire - Decimetre

## Slide 8

## Centimetre accuracy in real-time using survey quality GPS receiver and mobile phone communications;
Pilot Network since 2001;
Operational Network during 2006;
Trimble’s GPSNet Software for production;
Trialling Leica’s Spider software;
Coverage for cm accuracy includes 15km buffer around outside of network;
Coverage much larger for sub-meter corrections;
Supports post-processing;
Gives substance to NRMW’s role as Lead Agency in Queensland for GNSS.

- Centimetre accuracy in real-time using survey quality GPS receiver and mobile phone communications;
- Pilot Network since 2001;
- Operational Network during 2006;
- Trimble’s GPSNet Software for production;
- Trialling Leica’s Spider software;
- Coverage for cm accuracy includes 15km buffer around outside of network;
- Coverage much larger for sub-meter corrections;
- Supports post-processing;
- Gives substance to NRMW’s role as Lead Agency in Queensland for GNSS.

## Expanding User Base for Centimetre Accuracy

- Traditional Surveying users embracing online processing and real-time surveying – but the user base is moving beyond surveyors;
- New applications for centimetre accuracy, especially in “*Machine Guidance*” for Agriculture, Construction and Mining;
- High value and high cost industries where marginal improvements to efficiency bring large $ savings;
- Also a growing number of users who only need 10cm but with very high reliability (eg they require 5*sigma so 1*sigma must be 2cm)
- Reliance on high accuracy GNSS services by these new users is leading to a new category of *“liability critical”* applications so suppliers need to deliver 2cm @ 24/7!

## Machine Guidance with Centimetre Accuracy

***Leica Geosystems***

## Port of Brisbane:New Port Road and  Seawall built using GPS Machine Guidance

## Mine Safety

**Dragline Automation**

***Mining – A Major Industry for Queensland***

## Precision Agriculture

## Improved Shipping Guidance

## GNSS Applications in Queensland Governmenteg Queensland Rail...

## What about the future?...

***More Satellites***

## Global Navigation Satellite Systems (GNSS) are seeing many new developments in the next deacde and Australia and Queensland can be involved in all...

- USA’s GPS Modernisation and ultimately GPS-III (+ WAAS);
- Russia’s GLONASS Re-vitalisation; (+ its own Global SBAS?);
- EU’s Galileo (+ EGNOS);
- Japan’s QZSS (+ MSAS);
- India’s IRNSS (+ GAGAN);
- China’s Beidou and/or Compass;
- Australian Augmentations: GRAS, CORS etc...

## What about the future?...

***More Signals***

## GPS and Galileo Signals (let alone GLONASS!)

**Coded signals should make carrier phase tracking simpler and cheaper but which signals will be most useful and what receivers will be for sale?**
**With state-of-the-art technology for generating and processing multiple signals, will differential carrier smoothed ranging deliver centimetre accuracy?**

**C/A**

**OS/GPS III**

**L1**
**(1575.42 MHz)**

**E6**
**(1278.75 MHz)**

**L2**
**(1227.6 MHz)**

**L5**
**(1176.45**
**MHz)**

**M**

**P(Y)**

**PRS**

**PRS**

**CS**

**E5b**
**(1217.14**
**MHz)**

**L5**

**E5a***

**E5b***

**(OS)**

**(CS, SoL)**

## GALILEO1/GPS2 Receivers for Centimetre Accuracy...

- Decreasing cost

**A**: Top-of-line GNSS Rx tracks all sats, *highest* availability, *highest cost*, *highest* in DF-only & TF-only performance, *best hybrid*.
**B**: *Moderate cost* GNSS Rx tracks all sats, but does not track E6, GPS TF-only positioning available 2015, *good price/performance compromise*.
**C**: *Moderate cost* GALILEO-only surveying Rx, TF-only positioning available 2010, *unclear if tracking of E6 requires user charges for CS*.
**D**: *Lowest cost* GALILEO-only surveying Rx, DF-only performance (*similar* to current GPS-only performance in 2010), *uses OS signals only*.
- From Rizos, Higgins and Hewitson

| L11,2 | E61 | L2C2 | E51/L52 | # sats 2010; # sats 2015 | Comments |
| --- | --- | --- | --- | --- | --- |
| 30/2830/36 | 3030 | 1836 | 30/1030/28 | 60-DF1,28-DF2; 30-TF1,10-TF2 60-DF1,64-DF2; 30-TF1,28-TF2  | A
GPS+GALILEO |
| 30/2830/36 | -- | 1836 | 30/1030/28 | 30-DF1,28-DF2; 10-TF2 30-DF1,64-DF2; 30-TF1  | BGPS+GALILEO |
| 3030 | 3030 | -- | 3030 | 60-DF1; 30-TF1 60-DF1; 30-TF1  | C GALILEO |
| 3030 | -- | -- | 3030 | 30-DF1 30-DF1 | DGALILEO |

## What about the future?...

***More Infrastructure***

## A Major National Initiative for CORS

- National Collaborative Research Infrastructure Strategy
- $540m over 7 years
- Bids between 5m and 60m
- Infrastructure to encourage research in Australia targeting the National Research Priorities

***From Geoscience Australia***

## A Major National Initiative for CORS

- Capability Area on “*Structure and Evolution of the Australian Continent*”;
- Geospatial Reference Frame enhancement
-  Expanded VLBI, SLR, Gravimetry, GNSS;
- Improve the Realisation of ITRF in Australia
-  GNSS network covering majority of applications;
- State and Territory Cooperation.

***From Geoscience Australia***

## Proposed VLBI Network

***From Geoscience Australia***

## Proposed GNSS Network

- Cross continental GNSS transects for measuring intra-plate deformation
- Station spacing of 200km, resulting in users not being more then 100km from nearest CORS station
- Circum-continental coverage for measuring plate dynamics, and sea level change
- Major road and rail routes covered
- Major agricultural areas covered
- Major population zones covered
- Major areas of environmental research covered
- Some of the existing mining industry areas covered, although it is envisaged that this number would be increase by mine operators adding their sites collaboratively to the network.
- Major tourism areas covered

***From Geoscience Australia***

## From Geoscience Australia

***From Geoscience Australia***

## Queensland GNSS Infrastructure

***Queensland GNSS Infrastructure***

- Expansion of SunPOZ based firmly on GPS
- Galileo Sensor Station Tender for ESA
- Investigating a GLONASS Station

## Conclusion

- Carrier phased based positioning is a growth area due to the increasing number of users requiring centimetre accuracy;
- Delivering high accuracy GNSS services to new users with “*liability critical*” applications is a challenge;
- We are moving from an environment dominated by GPS to a multi-system, multi-signal environment, which is also a challenge;
- These issues require constant review to ensure provision of the necessary and suitable infrastructure.