BDS在低轨卫星编队高精度相对轨道确定上的应用分析

分析基于北斗卫星导航系统(BeiDou satellite navigation System, BDS)的低轨卫星编队相对轨道确定问题,但由于缺乏实测数据,通过仿真实验展开研究。结果表明,500 km空域平均可视BDS卫星数约为9.7,由于地球静止轨道(GeoStationary earth Orbit,GEO)卫星和倾斜地球同步轨道(Inclined GeoSynchronous earth Orbit,IGSO)卫星的存在,亚太地区的可视BDS卫星数明显偏多。仅考虑观测噪声的影响时,基于BDS的相对定轨精度可达0.74 mm,加入星历误差的影响,对近距离编队系统的相对定轨而言,GEO卫星数米的星历误差可以忽略,但当星间距离增大到约200 km时,GEO卫星单差后的星历误差可达厘米量级,GEO+IGSO+中圆地球轨道(Medium Earth Orbit,MEO)卫星和IGSO+MEO卫星求解的相对轨道精度分别为1.09 mm和0.96 mm,GEO卫星的加入使得精度下降了13.54%。在其余误差得到有效处理后,BDS的相对定轨精度可达亚毫米量级,且无明显区域差异,GEO卫星和IGSO卫星能提高近距离编队系统的全球相对定轨精度,未来BDS将广泛应用于低轨卫星编队相对轨道确定。

Precise relative orbit determination of LEO formation flying using BDS

The purpose of this paper is to study the Precise Relative Orbit Determination (PROD) for the Low Earth Orbit (LEO) formation-flying satellites based on BeiDou Satellite Navigation System (BDS). Due to the lack of experimental data, simulation method is used. Firstly, the average number of visible BDS satellites at altitude of 500 km is about 9.71. Because of the Geostationary Earth Orbit (GEO) satellites and Inclined Geosynchronous Earth Orbit (IGSO) satellites, the LEO satellites can observe more BDS satellites over the Asia-Pacific region. When only the observation noise is considered, the accuracy of PROD based on BDS is 0.74 mm. Furthermore, the influence of ephemeris errors is analysed. If the relative position between satellites is only a few kilometres, the effect of ephemeris errors on PROD could be ignored. However, for a 200km separation of the LEO satellites, the Single Difference (SD) ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and MEO satellites co-work with GEO satellites, the accuracy decreased from 1.09mm to 0.96mm, decreased by 13.54%. Finally, the conclusion is that the accuracy of PROD based on BDS can reach sub-millimeter level after the remaining errors are processed, the differences of the PROD results are not apparent between different regions. When relative position between satellites is only a few kilometres, GEO satellites and IGSO satellites can improve the accuracy of PROD all over the world. In the future, BDS will be widely used in PROD of LEO satellites.