Summary of feedback on the discontinuation of our DGPS service
We cited the increased accuracy of GPS and the introduction of other global positioning constellations including GLONASS, GALILEO and Beidou as being reasons why AMSA’s DGPS service is no longer needed.
We provided information about our plans to discontinue DGPS is on our website, and we invited feedback from anyone who believed safety of navigation would be adversely affected.
The feedback we received
We received four submissions expressing concern. The feedback is summarised as follows:
- Parts of Australia’s maritime industry stated there was still a dependence on AMSA’s radiobeacon DGPS for accuracy, and shutting it down could affect their operations.
- Some ships still use DGPS capable antennae and receivers, and they would need to replace them when DGPS is turned off.
- Some asked for more information on alternate systems for high accuracy positioning.
- One suggested IMO’s requirement for 10 metre accuracy was not good enough, and AMSA should be aiming for better accuracy.
- We were asked why we were not waiting until the Australia and New Zealand Space Based Augmentation System (SBAS) is available before shutting down DGPS.
- Advice from our formal stakeholder groups supported the decision and understood why AMSA was discontinuing the service.
Further information from us
To address the concerns of our stakeholders, we provide the following information:
- When DGPS is discontinued any GPS receiver, no matter how old, will still provide a GPS derived position. If you have an old receiver, you may wish to look at upgrading your receiver. Just like a mobile phone, the technology for GNSS antennae and receivers has modernised significantly over the last 20 years. If you are still using a pre-2003 GPS receiver it will continue to work, but a more modern receiver will provide a more reliable and accurate position with or without AMSA’s DGPS service. We suggest that for the best results, you should look to use a multi constellation, dual frequency receiver.
- Today, most GNSS receivers are capable of receiving an SBAS signal. The Australia/ New Zealand SBAS will become fully operational for the Australasian region by 2023. The new system will be called the Southern Positioning Augmentation Network, or SPAN, and will be a free service. For more information go to the Geoscience Australia website.
- AMSA’s DGPS service was introduced in the late 1990s to reduce up to 200 metres of error from Selective Availability, down to approximately 10 metres. The DGPS infrastructure has not been upgraded and should not be relied upon to provide any better accuracy than approximately 10 metres. It is now old technology, is limited by range, and due to its age is becoming more unreliable.
- Not all ships are fitted with DGPS capable receivers. DGPS requires an additional 300kHz receiver be fitted to make use of the DGPS radiobeacon signal. While some marine electronics manufacturers continue to make radiobeacon DGPS receivers, many are discontinuing their production.
- There are other options available in Australia for gaining higher accuracy positioning information. These include:
- AUSPOS Online GPS Processing Service. AUSPOS is a free online GPS data processing facility provided by Geoscience Australia. AUSPOS works with data collected anywhere on Earth. For more information go to AUSPOS - Online GPS Processing Service.
- AUSCORS NTRIP (Network Transport of RTCM via Internet Protocol) Broadcaster. Geoscience Australia (GA) provides 1 Hz data streaming from our Global Navigation Satellite System (GNSS) stations throughout Australia, Antarctica and the Pacific. The data is distributed via the AUSCORS NTRIP Broadcaster. Access to the data is free, however a username and password is required. The real-time data is made available through an RTCM standard transmitted over the Internet using the NTRIP (Network Transport of RTCM via Internet Protocol). For more information on this service go to AUSCORS NTRIP Broadcaster.
- A number of commercial companies also provide pay-for-use augmentation services. Many of these services provide decimetre accuracy or better. The cost for a satellite based augmentation service varies depending on the level of accuracy required.
- With the Australia/ New Zealand SBAS project underway, the test signal has been available for anyone to use. Geoscience Australia has indicated that the test signal will cease as of the 31 July 2020, but it is anticipated that a similar SBAS test signal will be available for use from 2021. To use this signal, you may need to do a firmware update to your SBAS capable receiver.
Testing for precision of GNSS positioning systems
- In May 2020, we worked with a number of organisations to assess and compare the performance of different GNSS positioning solutions. The testing compared the horizontal precision of single frequency GPS, single frequency GNSS, AMSA DGPS, and dual frequency GNSS.
- The preliminary results demonstrated the above GNSS positioning solutions provided a horizontal precision of within 0.9 metres, 95% of the time, and were all within 0.2 metres of each other.