接收机位置误差对GNSS定时的影响分析

Analysis of receiver position error impact on GNSS timing

不准确的接收机位置信息将会影响用户的定时结果。从理论推导和试验两方面研究了接收机位置误差对定时结果的影响。首先理论上通过对伪距观测方程求一阶微分推导得出定时接收机位置误差对定时的最大影响量;为排除卫星位置误差的影响,利用IGS提供的卫星精确位置,通过引入不同量级的接收机位置误差开展试验,对理论分析结果进行了验证;再通过接收机坐标置偏试验分析不同方向置偏不同量级的位置误差下GPS/GLONASS接收机的观测数据,分析了实际运行环境中的位置误差对接收机定时结果的影响。试验结果表明接收机的纬度、经度分量误差均会对定时结果的准确度和稳定度产生影响,纬度误差每增大1″,对GPS和GLONASS定时准确度的影响分别小于5、15 ns,对稳定度的影响分别小于10和15 ns;经度误差每增大1″,对GPS和GLONASS准确度的影响均小于1 ns,对稳定度的影响均小于10 ns;高程坐标分量误差每增加1 m,会出现约3 ns的定时偏差,对定时稳定度的影响则最大约0.3 ns/m。在实际应用中,用户可参考本文的结论根据所需定时精度的需求,考虑定时接收机输入坐标的精确度。

Inaccurate receiver position information directly influences the timing results for users. The impact of receiver position error on timing is studied in the terms of both theory and experiment. Theoretically, the biggest impact on receiver position error is obtained by differentiating the pseudo-range equation in the first order. To avoid the influence of satellite position error, the precise satellite positions provided by IGS are used to correct the theoretical results. In experiments, the impact of position error on timing result is also studied by analyzing GPS/GLONASS receiver observation data under the errors in different directions and orders of magnitude. The different situations in the practical scenarios are also analyzed. Experimental results show that the timing accuracy of GPS and GLONASS is less than 5and 15 ns by every increase of 1 are second latitude error, and timing stability is less than 10 and 15 ns respectively. The timing accuracy of GPS and GLONASS is less than 1 ns for each additional arc second error of longitude, and both less than 10 ns of timing stability. Every increase one meter of elevation error can cause about 3 ns timing error and the influence on timing stability is about O. 3 ns/m. In the practical applications, users can refer to this conclusion for considering input coordinates of timing receivers according to the demand of timing precision.