北斗三号与北斗二号基本导航电文参数比较

Basic navigation message parameters comparison between BDS-2 and BDS-3

针对北斗二号系统和北斗三号系统导航电文播发现状,该文从导航电文结构、导航电文内容和播发方式等方面对二者间的差异进行了比对分析,着重比较分析了卫星星历参数、卫星钟差钟差、数据有效性标识、设备群延迟参数、设备延迟参数、电离层改正、完好性等导航电文参数,并结合导航电文实际应用,给出了广播星历拟合精度、卫星钟差拟合精度、系统定位精度评估结果。结果表明:北斗卫星广播星历拟合残差为厘米级,18参数广播星历拟合精度略优于16参数的拟合精度;加入星间链路钟差后,MEO卫星的钟差测定精度虽与仅星地观测的钟差精度基本相当,但明显提高了卫星钟差预报精度;北斗二号与北斗三号联合定位精度较仅北斗二号卫星定位精度有所提升。

As to the propagation state of the navigation message parameters of BDS-2 and BDS-3,the paper compared the differences in data construction,navigation message and propagating models,especially in ephemeris,satellite-clock error,data availability identification,device group delay,ionosphere correction,integrity and so on. What’s more,the paper assessed the fitting precision of ephemeris and clock error and positioning accuracy with observation data. The results showed that the ephemeris fitting residual could be researched centimeter level precision,the ephemeris with 18 parameters is slightly better than the ephemeris with 16 parameters;as the combination with inter-satellite link data,the clock prediction accuracy of medium earth orbit(MEO)satellite had been improved dramatically,through the clock determination accuracy was approximately the same with the clock determination accuracy calculated by satellite-ground data;the combined positioning accuracy of BDS2 and BDS3 was better than the BDS2 positioning accuracy.