BDS/GPS实时钟差估计中ISB分析与函数模型设计

ISB Analysis and Function Model Design in the Real-time BDS/GPS Clock Estimation

实时钟差产品是高精度广域差分位置服务(亚米级、分米级、厘米级)的基础产品,通过研究BDS/GPS融合的ISB,研究了各类型接收机BDS GEO/IGSO/MEO ISB差异,提出了在BDS/GPS联合的实时钟差估计中引入3个ISB参数的函数模型,在此基础上基于非差法实现了BDS/GPS联合的实时钟差估计。采用MGEX和湖南CORS实时观测数据进行了实时钟差解算,利用i GMAS产品综合中心提供的事后精密钟差产品作为基准,对比分析了新方法与原有方法的实时钟差产品的精度差异。结果表明,该方法与原方法估计的GPS钟差精度相当,对BDS实时钟差精度改进显著,尤其对BDS IGSO/MEO卫星,改进幅度在20%以上,验证了算法的有效性。

The real-time clock product is the basis products for the high precision wide-area positioning service.Focus on inner-system bias of BDS/GPS,we have studied the ISB difference of BDS GEO/IGSO/MEO with various GNSS receivers,and then proposed three ISB parameters model, finally real-time BDS/GPS clock estimation is achieved with undifferenced method. The BDS/GPS observations of 78 MGEX global sites and 2 Hunan province CORS site are collected to generate the real time clock products that was compared with the final iGMAS precise clock product in two strategies （ the old model and the new model）. The results show that the accuracy of GPS clock estimation is equivalent with the two strategies,and the accuracy of BDS clock estimation is improved significantly with the new method, especially for the BDS IGSO/MEO satellite, the improvement is more than 20%, which verifies the validity of the algorithm.