星载GPS几何法实时定轨有关问题的研究

首先讨论了星载GPS几何法实时定轨的绝对定位方法和各种差分技术。由于伪距差技术能克服GPS卫星的星历误差、卫星钟误差，特别是SA误差的影响，而且实现难度不大，所以应用它来实时定轨。实测数据的处理表明，它能明显提高定轨的精度。然后分析了星载GPS所受扰动影响的情况，对应用抗差估计削弱GPS卫星信号扰动的影响进行了试验，试验的结果说明抗差估计能进一步提高星载GPS几何法定轨的精度。

Study on the Relative Problem of GPS-Based Geometric Orbit Determination in Real Time

First,the point positioning and all sorts of differential GPS techniques are discussed on GPS based geometric orbit determination in real time.Differencing pseudo range is proposed to use to determine the satellite geometric orbit in real time because it can weaken the effect of GPS satellite orbit error and clock error,and particularly effect of SA,and because it is not difficult to carry out.The result computed from practical observation proves that it can improve the precision of geometric orbit determination obviously.Then,robust estimation is tested to weaken or eliminate the effect of contaminated GPS based signal,and the result verfies that robust estimation can improve the precision of geometric orbit determination further.