Differential GPS Corrections for the Error in the Nominal Location of Reference Station

Abstract

In the differential GPS systems, the difference of atmospheric propagation delay between user site and reference station introduces some position error. Among this effect, the difference of tropospheric propagation delay could be corrected using the location of the reference station, and user position accuracy could be improved. This correction is based on the location of reference station which is provided to user, or the nominal location, thus quantization error of this nominal location, which is relatively large for the SLAS service of the Quasi-Zenith Satellite System, produces additional position error through this correction. And, relocation of the reference station far from the nominal location possibly emphasizes such an effect and raises unignorable large error. The author reports the detail of the effects due to the difference of the nominal location and true location of the reference station and correction method for this effect. It is confirmed that position error up to 20 mm due to quantization error of nominal location for the SLAS service is cancelled and position error induced by relocation of the reference station is also reduced largely.