A New Satellite Clock Offsets Prediction Method Based on the IGS RTS Products

Abstract

Satellite clock offsets prediction is crucial for GNSS applications and has attracted much attention from the GNSS community. However, previous satellite clock offset prediction was mostly carried out based on the IGS rapid products or IGS final products. Limited by the long latency of the above products, the predicted satellite clock offset cannot meet the requirements of high precision real-time applications such as real-time PPP. In this paper, a new satellite clock offsets prediction method based on the IGS real-time service (RTS) products is proposed, in which the satellite clock drifts from the broadcast ephemeris are used as the pseudo-observations. For the polynomial part, only clock drift and clock drift rate are estimated while the latest clock offsets are directly applied. The GPS satellite clock offsets are predicted all together by considering the datum change involved in the IGS combination process, which is observed in the IGS01 clock products. The results show that the standard deviations of the predicted IGS01 products are 1.408 ns and 0.079 ns for the traditional method and proposed method, respectively. For the IGS03 products, the corresponding standard deviations are 0.243 ns and 0.080 ns. The proposed satellite clock offset prediction method provides better clock prediction performance based on the IGS RTS products.