An Approach of Network Code Differential GPS Positioning for Medium and Long Distances

This contribution presents an approach of network code DGPS post-processing positioning with the use of at least three simultaneous reference stations. The traditional DGPS is based on only one reference station. Using only one reference station, a rover receiver does not have redundant observations. The accuracy of DGPS positioning is very difficult to estimate and, in some DGPS receivers, is not valid or the DGPS positions are determined without estimated accuracy. In practical experiments worldwide, it has been shown that code DGPS accuracy varies from approximately 1 to 2 meters depending on the number of satellites and their configuration. This paper presents new functional and stochastic models of network DGPS positioning for medium and long distances, allowing centimeter accuracy for some epochs with valid accuracy estimation based on variance covariance (VC) matrix. Valid accuracy estimation is an extremely important issue from a practical point of view for allowing large enhance of DGPS applications. Practical calculations and analysis of the approach have been presented with the use of GPS data from the ASG-PL (Polish Active Geodetic Network) network.