Differential GPS reference station algorithm-design and analysis

The global positioning system (GPS) allows properly equipped users to determine their position based on the measured pseudoranges to at least four satellites. Differential GPS operation (DGPS) uses a reference station at a known location to calculate and broadcast pseudorange corrections to local users, resulting in improved user position accuracy. DGPS accuracy is limited by the ability of the reference station to remove the effects of receiver measurement noise and multipath errors from the broadcast corrections. This article presents two new algorithms for DGPS reference station design. The accuracy of the algorithms is analyzed both theoretically and experimentally. The single and two frequency reference station algorithms, respectively, achieve 6 dB and 20 dB improvement relative to the raw corrections.