基于非差与历元差分两种观测模型估计精密卫星钟差的方法比较

摘要

The estimations of precise satellite clock difference with non-difference model and the epoch differential model were studied, and the characteristics of the two models were compared through analyzing the computing speed and precision. Test results show that the estimate based on zero-differential model has high precision and high reliability, more observation information can be used, and the ambiguity fixing also can be realized, but it needs more unknown parameters, the computing speed is slow, and the high resultant precision needs a converging produce gradually. While with the epoch differential model, the estimate needs less unknown parameters, the efficiency of computation is high, and the precision doesn' t need the converging produce, but compared with non-difference model its precision is lower, and the initial value should be extracted from the navigation messages or obtained through other ways. The systematical biases caused in that way will be absorbed by the ambiguity and receiver' s clock error and it won't influence the final positioning results.%研究了非差与历元差分两种观测模型估计精密卫星钟差的方法,评价了分别利用两类观测模型估钟的特点.通过实际算例分析了两种观测模型估钟的处理速度与精度.计算结果表明:基于非差观测模型估计卫星钟差精度高、观测信息没有损失、可靠性高、可以实现模糊度固定,但由于未知参数多,解算速度较慢,且需要经过一段时间的收敛才能达到所需精度;而历元差分模型估计卫星钟差待求参数较少,计算效率高,且不存在收敛过程,但估钟精度比非差模型估钟收敛后的精度略低,且得不到钟差初值,需从导航电文中提取或通过其他方式获取,不过由此引起的系统性偏差,在定位时可被模糊度和接收机钟差吸收,不影响最终的定位结果.