BDS/GPS对流层延迟估计及对精密单点定位的影响

BDS/GPS Zenith Tropospheric Delay Estimation and Its Effect on Precise Point Positioning

针对对流层湿延迟参数估计及水平梯度处理策略对精密单点定位影响的问题,以9个多系统实验网实测数据为基础,设计了6种对流层延迟处理方案并进行实验.实验结果表明,观测时长在8 h时段内,BDS/GPS定位模式下,对流层延迟的水平梯度处理不宜采用随机游走模型;采用随机游走估算对流层湿延迟参数,且不估算或使用分段常数处理水平梯度的策略相对占优.动静态精密单点定位结果显示,BDS/GPS采用分段常数或随机游走进行对流层湿延迟参数估算和分段常数处理水平梯度的策略相对占优,采用随机游走处理水平梯度的策略稍弱.总体而言,BDS较GPS估算的对流层延迟及定位精度稍弱;海洋周边6种方案解算结果差异较内陆站大.静态精密单点定位模式下,随着观测时长的增加,6种方案定位误差趋势趋于一致,误差大小基本在2 cm内,观测时长大于12 h时,随机游走估算对流层湿延迟参数和不考虑水平梯度的处理策略整体较优.

The influence of zenith wet delay parameter estimation and horizontal troposphere gradient processing strategy on precise point positioning is studied,Six zenith tropospheric delay processing schemes were designed and experimented on the basis of the measured data from nine Multi-GNSS Experiment stations.The experimental results show that,during the 8 h observation period,it is not suitable to use the random walk model to deal with the horizontal troposphere gradient of the zenith wet delay in the BDS/GPS Precise Point Positioning mode;and the strategies of estimating the zenith wet delay parameter by random walk and handling the horizontal troposphere gradient without estimating or using the piecewise constant are relatively advantageous.The results of the dynamic and static precise point positioning show that the BDS/GPS strategy of estimating the zenith wet delay parameter and processing the horizontal troposphere gradient with piecewise constant or random walk is relatively superior,while the strategy of processing the horizontal troposphere gradient with random walk is slightly weaker.Overall,the zenith tropospheric delay and precise point positioning accuracy estimated by BDS is slightly weaker than that by GPS;the differences in the results of the six schemes around the ocean are larger than those of the inland stations.In the static Precise Point Positioning mode,with the increase of observation time,the trend of Precise Point Positioning errors of the six schemes tends to be the same,and the error size is basically within 2 cm.When the observation time is longer than 12 h,the strategy of estimating the zenith wet delay parameter by random walk and not considering the horizontal troposphere gradient is better overall.