北斗三号GEO卫星的RDSS定轨精度分析

有源服务模式RDSS(Radio Determination Satellite Service)所具备的通信、导航一体化特性是我国北斗卫星导航系统的重要特色之一.为进一步提高RDSS的通信服务能力,并保障RDSS服务系统的健壮性,北斗三号RDSS服务从系统架构到信号体制都进行了很大改进.本文首先分析了新的信号体制下,RDSS测距在测量模型和观测噪声等方面的误差特性,并比较了其与原有信号体制的不同.为了避免在RNSS(Radio Navigation Satellite Service)载荷故障时RDSS不能正常提供导航服务的情况发生,RDSS系统需要能够仅利用RDSS测距完成GEO测轨,以此作为原有RNSS测轨的备份保障.文章进一步分析了这种情况下,仅利用RDSS测距进行GEO定轨的精度.通过实测数据分析,我们发现其精度可优于10 m,利用该轨道信息的定位、定时精度可以满足服务指标要求.

Precision analysis of BDS-3 GEO satellite orbit determination using RDSS

Providing communication and navigation services simultaneously using the radio determination service system(RDSS)is one of the significant and unique features of the Beidou navigation satellite system(BDS).In order to further enhance the service capabilities and ensure the service robustness,the RDSS system of BDS-3 has been significantly improved from system architecture to signal system.In this study,error characteristics of the RDSS with a new signal system are analyzed considering both measurement model and observation noise.Then,the results are compared with those of the BDS-2 system.It is found that in order to avoid the failure of the RDSS navigation service during the radio navigation satellite service load breakdown,the RDSS system needs to have independent orbit determination ability.Furthermore,precision of the GEO orbit determination is analyzed when only the RDSS is employed.Analyzing the measured data reveals that the orbit determination accuracy would be better than 10 m,where positioning and timing accuracy can meet the service requirements.