姿态模式切换期间QZSS卫星轨道及其钟差产品特性分析

Analysis of Characteristics of QZSS Satellite Orbit and Clock Products during Yaw Attitude Model Switching

导航卫星姿态控制模式切换对精密定轨解算得到的轨道和钟差均有较大影响。本文首先从理论上分析了卫星偏航姿态及其对精密定轨的影响,然后分别以卫星激光测距检核和钟差多项式拟合的方法对IGS MGEX分析中心的QZSS卫星轨道和钟差产品精度进行评价,最后以谱分析方法和改进阿伦方差揭示了卫星钟差的周期特性。基于2014年全年的QZSS卫星轨道和钟差产品的研究表明,一年内有两次长约20 d的地影季,太阳角呈现半年周期的波动;QZSS卫星在低太阳角时有零偏保护,其卫星轨道和钟差精度都与太阳角有显著相关性;卫星钟差具有与轨道周期相近的周期项,且周期项振幅与太阳角的大小也具有相关性,表明现有的定轨策略存在不足。考虑到QZSS与目前北斗星座中IGSO和MEO卫星姿态控制模式的相似性,该结论对于研究我国BDS姿态切换期间的精密定轨有一定参考价值。

Yaw attitude model switching of navigation satellites have great impact on its orbit and clock products derived from precise orbit determination.Firstly,the yaw attitude and solar radiation model of QZSS is given briefly.Then,using QZSS precise orbit and clock products provided by IGS MGEX analysis center,precision of orbit and clock is analyzed by satellite laser ranging residuals and polynomial fit residuals respectively.Finally,spectral analysis and modified Allan variance is carried out on clock products to reveal its periodic variations.Research on QZSS satellite orbit and clock products of 2014 shows that there are two eclipse seasons of 20 days and the beta angle is fluctuating with a period of halfyear.And there is significant correlation between the precision of orbit and clock products and beta angle.Moreover,the satellite clock offset has periodic variations similar to orbit periods and its amplitude is changing with the beta angle which indicates problems of current orbit determination strategies.In view of similarities between QZSS and BeiDou IGSO and MEO satellites in yaw attitude model,the conclusion is beneficial to improve BeiDou precise orbit determination.