星地双向伪距模型仿真比较

给出了星地双向测距中,上下行伪距观测值的数学模型。研究了几何距离项、星地钟差影响、地球自转及各项误差修正量在上下行伪距中的差异,并对其进行了量级分析。通过计算得出由于传播时延的影响上下行几何距离项相差较大,在上下行组差时应予考虑。其他各项修正量上下行互差较小,在组差计算时可不予考虑。最后针对GPS 04星仿真计算了上下行伪距值,由此得出由于星地钟差的影响,其互差可达约10 km。

Two-way Pseudorange Model and Simulation Comparision

Mathematic models of the up and down link pseudorange in two-way distance measurement were given in this paper.The differences of geometrical distance,satellite and station clock offset influence,earth rotation correction and other error corrections between up and down link were studied.And their magnitudes were analyzed.Through calculation we educed that there were big difference between up and down link geometrical distance because of transmiting time delay.When we used the two-way pseudorange data by difference,this influence had to be considered.But the differences of other corrections were so small that they could not be taken into account.At last the up and down link pseudoranges of GPS 04 satellite were simulated.Because of the satellite and station clock offset,the difference could reach ten thousand meter.