Effect of Troposphere Parameter Estimation on BDS PPP

To investigate the effect of the tropospheric wet delay parameter estimation on BDS precision point positioning (PPP), observations from 13 global MGEX stations are selected over 24 days for static PPP using four parameter estimation methods: Random walk (RW), Piecewise Constant estimation (PWC: 120/180/360, estimated every 120/180/360 min). The results of the tropospheric zenith delay (ZTD) and PPP positioning are evaluated using the ZTD product and the weekly solution product provided by IGS. The ZTD time series and ZTD accuracy of the four parameter estimation methods are analyzed, and the applicability of the four parameter estimation methods is further validated by the PPP positioning accuracy. The experiments show that RW and PWC:120 are suitable for the case of drastic overall ZTD variation, whereas PWC:180 and PWC:360 are suitable for the case of gentle overall ZTD variation; furthermore, it is observed that selecting a suitable parameter estimation method leads to an improvement in both ZTD accuracy and PPP positioning accuracy. According to those results, we recommend the following order of preference for the four parameter estimation methods: RW, PWC:120, PWC:180, and PWC:360, based on their respective strengths.