Differential GPS services and accuracies

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There are a variety of delivery mechanisms for the correction signal.

The most common are radio broadcasts and satellite broadcasts (not GPS satellites).

Radio Broadcast

Radio broadcast - the General Lighthouse Authority (GLA) offer a free medium wave radio broadcast service aimed at mariners. The corrections are computed and transmitted by GPS receivers at lighthouses. The accuracy of the correction varies with distance from the lighthouse. For more information on using this service with your GPS receiver, contact the receiver manufacturer.  For information on the service click here.

The GLA service improves the positional accuracy of a single GPS receiver to the 1-2m level.

Satellite broadcast

These systems use geostationary satellites to beam down a footprint of corrections covering a wide area (for example, the UK). One such system is Fugro's™ OmniSTAR®. This type of system is usually available by subscription and they are based on a network of GPS receivers. The broadcast corrections are valid across the whole footprint area. Accuracy does not tend to vary with distance from a network GPS receiver and is more uniform over whole of the correction footprint.

These systems will improve the positional accuracy of a single GPS receiver to the sub-1 m-1 m level. For more information on using these services with your GPS receiver, contact the receiver manufacturer.

Fugro and OmniSTAR are trademarks of Fugro plc.