Differential Global Positioning System (DGPS) is a technology that enhances the positional data available from global navigation satellite systems (GNSS). It can increase the accuracy of a GPS system from approximately 15 metres to 1–3 centimetres.
DGPS works by using a network of fixed position, ground-based reference stations. Each station calculates the difference between its highly accurate known position and its less accurate satellite-derived position. The stations then broadcast this data locally, which non-fixed (mobile) receivers use to correct their position by the same amount, thereby improving their accuracy1.
The United States Coast Guard (USCG) previously ran DGPS in the United States but it was discontinued in March 2022. Other countries have their own DGPS implementations. A similar system which transmits corrections from orbiting satellites instead of ground-based transmitters is called a Wide-Area DGPS (WADGPS).
DGPS is an important tool in modern navigation and is used by military personnel and professional surveyors to navigate accurately and reliably. It uses additional reference stations to provide more accurate and reliable positioning data. The biggest benefit of DGPS is how land surveyors can achieve improved accuracy and reliability. In general, a DGPS can achieve accuracies of 1-3 meters, depending on a variety of factors. This means that land survey measurements can be conducted with greater precision and reliability. DGPS is perfect for surveying, construction, navigation, mapping, and engineering purposes.