北斗三号PPP-B2b信号精密单点定位服务可用性分析OA

Aiming at the availability of BDS-3 PPP-B2b service,a systematic analysis has been conducted towards the availability ratio of PPP-B2b corrections,the average number of satellites with available corrections and the matching characteristics of PPP-B2b corrections.The results show that in China and surrounding areas,the availability of BDS-3 PPP-B2b corrections is between 71％and 95％,and reaches the maximum in Beijing.While that for the GPS system is between 68.5％and 88.6％,which is worse than the BDS-3.The satellite observation arcs lack of PPP-B2b corrections are mainly concentrated in low elevation angle periods for users in China and surrounding areas,and the availability of PPP-B2b corrections will increase with the increase of cut-off elevation angle.The average number of satellites with available PPP-B2b corrections for BDS-3,GPS and BDS-3/GPS systems in China and surrounding areas is about 8,7 and 15 respectively,which can ensure effective real-time PPP service performance.However,on average,about 1 BDS-3 satellite and 2 GPS satellites cannot participate in the real-time PPP positioning due to the lack of PPP-B2b corrections for users in the area.For areas south of the equator,BDS-3 only or GPS-only system is basically unable to provide effective real-time PPP services with the average availability of PPP-B2b correction being less than 50％,but the BDS-3/GPS dual system can provide about 7 to 11 available satellites in some low latitude areas.Users should be noticed that there will be a temporary mismatching state between the orbit and clock offset corrections each time when the IOD Corr parameter changes due to the different updating frequency.