GPS navigation knowledge-DGPS

DGPS introduction DGPS is short for English difference global positioning system, that is, differential global positioning system. A precise known location (reference site)Install the GPS monitoring receiver to calculate the number of distance corrections between the reference station and the GPS satellite. The difference value is usually called PRC (pseudo distance correction value). The reference station transmits the data to the User Receiver for error correction, thus improving the positioning accuracy. DGPS is an effective method to overcome the negative effects of SA and improve the GPS positioning accuracy, which can reach level III and above. DGPS can be generally divided into single-station DGPS, multi-benchmark station area DGPS, wide area DGPS and global DGPS, global DGPS is brewing. Edit the DGPS principle in this section. Currently, the positioning accuracy provided by the GPS system is better than 10 meters. To achieve higher positioning accuracy, we usually adopt the differential GPS technology: place a GPS receiver on the reference station for observation. Based on the precise coordinates known by the reference station, the number of distance corrections made from the reference station to the satellite is calculated, and the reference station sends the data in real time. While conducting GPS observation, the user receiver also receives the number of corrections sent by the reference station and corrects the positioning results to improve the positioning accuracy. ^{[1] Differential GPS is divided into two categories: pseudo-range difference and carrier phase difference. The pseudo-Distance Difference Principle is the most widely used difference. On the reference station, observe all satellites and obtain the real distance from each satellite to the Reference Station at each time point based on the known coordinates of the Reference Station and the coordinates of each satellite. Then compare with the measured pseudo-margin to obtain the number of pseudo-margin corrections and transmit them to the user receiver to improve positioning accuracy. This difference can be used to obtain meter-level positioning accuracy. For example, the widely used "Beacon difference" Carrier Phase Difference Principle Carrier Phase Difference technology, also known as the real time kinematic technology, it is a real-time differential method for processing the carrier phase observations of two stations. That is, the carrier phase collected by the benchmark station is sent to the user receiver to calculate the coordinate of the difference. The carrier phase difference can make the positioning accuracy reach the centimeter level. It is widely used in dynamic fields that require high-precision positions.}