Differential GNSS

Common card · No. 447433

Differential GNSS (DGNSS), including differential GPS (DGPS), supplement and enhance the positional data available from global navigation satellite systems (GNSS), such as the American Global Positioning System (GPS) and other similar systems. A DGPS can increase accuracy of positional data by about a thousandfold, from approximately 15 metres (49 ft) to 1–3 centimetres (1⁄2–1+1⁄4 in). A DGPS system consists of networks of fixed position, ground-based reference stations. Each reference station calculates the difference between its highly accurate known position and its less accurate satellite-derived position. The stations broadcast this data locally—typically using ground-based transmitters of shorter range. Non-fixed (mobile) receivers use it to correct their position by the same amount, thereby improving their accuracy. Direct correction of position estimates is called observation-space correction. The United States Coast Guard (USCG) previously ran DGPS in the United States on longwave...

Read on Wikipedia · Image bdk, CC BY-SA 3.0