An Improved Method for BDS Inter-frequency Clock Bias Estimation

Abstract

Inter-frequency clock bias (IFCB) should be considered when performing triple-frequency GNSS precise point positioning (PPP). Traditional approach of IFCB estimation is by averaging IFCB of all stations. However, this method doesn’t consider the variation of receiver IFCB, so the averaged receiver IFCB is lumped into satellite IFCB. If the receiver IFCB can’t eliminate by averaging when station number is limited, this method is not theoretical compactness. In this paper, we propose a more compactness IFCB estimation method based on network solution. In this method, the satellite and receiver IFCB are estimated together under a constraint of satellite IFCB. To validate this method, we select a 60-days global MGEX data and estimate the BDS IFCB between B1B2 and B1B3. Results show that BDS IFCB is within 10 cm and the RMS for all satellites are within 3 cm, while for receiver IFCB, it has a similar periodic performance as satellite. After correcting IFCB in kinematic PPP using B1B3 combination, statistical results among 13 MGEX stations show about 0.5 cm improvement in horizontal and vertical comparing with uncorrected IFCB PPP solution.