BDS-3/GNSS satellite ultra-rapid clock offsets estimation model with the aid of onboard clock states solution
The orbit and clock offset of GNSS are the prerequisite for the high-performance positioning,navigation and timing(PNT)services.To overcome the obvious problems of clock offsets estimation in multi-GNSS ultra-rapid orbit determination solution,such as the observation quality and model configurations,an improved model to estimate ultra-rapid clock offset is proposed by considering the BDS-3/GNSS satellite clock states.Firstly,the observation equation of clock offset estimation by inserting the clock offset velocity and acceleration terms is constructed based on the fixed ultra-rapid orbit and station positions.Secondly,the algorithms of time-difference carrier phase(TDCP)and singular decomposition are used to construct the quality control and epoch-transition model of clock offset estimation.Thirdly,with the introduction of clock parameter states transi-tion equation and consideration of BDS-3/GNSS onboard clock frequency stability,the single-epoch estimated clock offset can be obtained.According to the proposed BDS-3/GNSS ultra-rapid clock offset estimation method,an accuracy improvement at least 46.9％can be obtained,where the instantaneous clock offset of epoch interval can be directly derived using the clock state values.In addition,compared with the traditionally issued BDS-3/GNSS ultra-rapid clock offsets,the four-system kinematics PPP performances of positioning and convergence are improved with 1.7％,6.0％,31.2％and 44.9％,33.3％,38.9％for E,N and U directions,respectively.Meanwhile,the accuracy of the predicted clock offset is also improved,which can lead to the decreasing of four-system static PPP positioning residuals and convergence time with 6.3％,13.5％,11.3％and 14.5％,1.6％,12.4％for E,N and U directions,respectively.Therefore,the quality of BDS-3/GNSS satellite ultra-rapid clock offset is significantly improved by the proposed estimation method,which can also be used to improve the multi-GNSS constellation performances of real-time and near-real-time services.
BDS-3/GNSSsatellite ultra-rapid clock offsettime-difference carrier phaseclock offset statesquality control
万方数据
维普
