Differential Global Positioning System


The Maritime and Port Authority of Singapore (MPA) has set up facilities to broadcast Differential Global Positioning Service (DGPS) signals at Raffles Lighthouse since 9 October 1997. The facilities  have been upgraded in 2010 and a new station has been installed at Horsburgh Lighthouse to increase  the DGPS signal coverage. The aim of providing the DGPS broadcast service is to further enhance navigational safety in the Singapore Strait, its approaches and its port waters.  It provides reliable, all-weather and round-the-clock DGPS data with 99% availability. This service is still offered free-of-charge to the shipping community and the public equipped with DGPS receivers.

The DGPS service is provided via the marine radio beacon operating in the Medium Frequency (MF) band. The message format of the broadcast is based on international standards adopted from the Radio Technical Commission for Maritime Services, Special Committee 104 (RTCM SC-104).

The DGPS Reference Stations at Raffles and Horsburgh Lighthouses are equipped with highly accurate GPS receivers and a real time integrity monitoring station which verifies the accuracy of the DGPS data. Should the accuracy of the data fail, the system provides timely warnings to users  that the data should not be used.

The technical details of the systems are summarised in the table below.


Please direct any further enquiries that you may have to The Chief Hydrographer of the Hydrographic Department