Extended Differential GPS

Alison Brown

Abstract: The Radio Technical Commission for Maritime Service (RTCM) Special Committee 104 on Differential GPS, established a standard data format for providing differential GPS services. This format has been used successfully for a number of different applications and differential GPS accuracies of 15 ft (1) using C/A code receivers have been demonstrated. The RTCM SC-1 04 differential GPS navigation message lumps together the errors from a number of different sources in the satellite pseudo-range corrections that are broadcast. This results in the differential navigation accuracy degrading if the user is operating at a distance from the differential reference station. Generally, the user must be within 100 nmi of the reference station to benefit fully from the differential GPS corrections. An Extended Differential GPS concept is presented in this paper which extends the range of operation of the differential GPS message. By using a network of differential GPS stations, a differential GPS message can be computed which provides corrections for the different components of the pseudo-range error. This allows the differential GPS navigation accuracy to be extended to a range of 1000 nmi from the master differential station.
Published in: Proceedings of the 1989 National Technical Meeting of The Institute of Navigation
January 23 - 26, 1989
San Mateo, CA
Pages: 125 - 136
Cite this article: Brown, Alison, "Extended Differential GPS," Proceedings of the 1989 National Technical Meeting of The Institute of Navigation, San Mateo, CA, January 1989, pp. 125-136.
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