Shutdown of AMSA’s differential global positioning system service

Marine Notice 03/2020 – Shutdown of AMSA’s differential global positioning system (DGPS) service

This marine notice informs vessel owners, operators and masters of the shutdown of AMSA’s radiobeacon differential global positioning system (DGPS) service from 1 July 2020.

AMSA established its radiobeacon DGPS service in the 1990’s, to improve the accuracy and integrity of global positioning system (GPS) information for ships navigating off the coast of Australia. At the time, the publicly available GPS signal was intentionally degraded, resulting in large position errors of up to 200 metres. Augmentation was necessary to correct for these errors and meet minimum requirements for maritime positioning and navigation.

In the year 2000, the intentional error in GPS positioning was removed. Since then, system technology has improved and the GPS constellation has been modernised. Observed positional accuracy for unaugmented GPS now consistently meets IMO requirements for accuracy in harbour/harbour-approach navigation.

How will the discontinuation impact you?

For the vast majority of maritime users, the discontinuation of AMSA’s DGPS service will not impact the accuracy of satellite positioning or safe navigation.

DGPS receivers will no longer receive the AMSA radiobeacon DGPS signal in areas where it was previously available. This may generate a ‘lost signal’ alarm, but your receiver will still provide a GPS derived position.

Alternate sources for high accuracy positioning

Other options are available for obtaining higher accuracy positioning in Australia.

For more information:


Sachi Wimmer
Deputy Chief Executive Officer
Australian Maritime Safety Authority

Selden Asymetric Rib Technology
Cyclops Marine
Jeanneau JY60
M.O.S.S Australia
West Systems