掩星观测中电离层延迟对LEO卫星轨道误差的响应

Response of ionospheric phase delay to LEO′s orbit biases in radio occultation methodology

从Haselgrove和Budden方程出发 ,模拟了GPS信号在电离层中的传播过程。利用GPS/MET实验中 5组GPS和LEO卫星的实际轨道 ,分别模拟了无LEO卫星轨道扰动和有轨道扰动情况下的GPS信号在电离层中的传播 ,并生成了对应的电离层延迟量。以同步生成的模拟精度序列为参照 ,就掩星观测中电离层延迟对LEO卫星轨道误差的响应程度进行了估计和分析。初步结果显示 :在掩星观测中 ,电离层延迟对LEO卫星轨道误差的响应比中性层延迟要弱得多 ,这可能同采用了电离层掩星观测的采样频率比中性层采样频率低两个数量级的技术手段有关。

Based on Haselgrove′s and Budden's Equations, the propagation process of GPS signal in the ionosphere is simulated. Five groups of orbit data for GPS and LEO satellites are employed to simulate and generate the ionospheric phase delay in two cases respectively: one is LEO orbit without forced perturbation and the other is LEO orbit with forced perturbation. With the simultaneously generated precision series, the response of ionospheric phase delay to the LEO satellite orbit biases is assessed and analyzed. The preliminary results have shown that the response of ionospheric phase delay to the LEO orbit biases is much weaker than that of neutral atmospheric phase delay. This perhaps due to the technique that the sampling rate for ionospheric observations is two orders smaller of magnitude than that of neutral atmospheric observations.