Sercel high-precision real-time differential GPS principles and results

The authors describe DGPS (differential Global Positioning System) equipment capable of high accuracy, the methods and format used, and the type of transmission. They also present the results acquired at sea during the first experiments conducted with the hydrographic service of the French Navy. It is concluded that this first stage has led to the capability of providing a lightweight DGPS monitoring reference station which may be set up anywhere in one day, and which offers a reliable few-meter accuracy for distances up to more than 500 nautical miles