BDS卫星失效对区域定位精度的影响评估

Evaluation of the Impact of BDS Satellite Failure on Regional Positioning Performance

基于STK软件实现了2016-09BDS系统星座结构的仿真,并选取可见卫星数、DOP值、系统可用性作为评估BDS卫星星座设计结构的指标,分析单颗与全部倾斜轨道卫星(IGSO)、地球静止轨道卫星(GEO)失效后对我国大陆地区BDS系统可用性的影响。结果表明,IGSO4卫星与GEO5卫星失效后对BDS在区域的定位性能影响较大,失效后的GDOP值分别为1.98、2.16。取BDS卫星正常运行时区域平均GDOP最大值(S=2.60)作为系统可用性阈值时,系统可用性分别降低了1.79%、32.63%;阈值取2S(5.20)、3S(7.80)、4S(10.40)、5S(13.00)时,系统可用性均可达100.00%。GEO整体失效后BDS系统在高精度定位中仍部分可用,而IGSO整体失效后BDS系统可用性受到大幅度限制。因此,增加在轨备份卫星时需重点考虑GEO5、IGSO4,并适当增加IGSO卫星的数目。

In this paper,based on the STK software,the simulation of the BDS satellite constellation structure in September 2016 is carried out.The average visible satellite number,DOP value and system availability are taken as indexes to evaluate the constellation design structure.After the failure of single satellite and all tilted satellite(IGSO)and geostationary satellite(GEO),the impact of satellite failure on the availability of BDS in China's Mainland is analyzed.The results show that the latency of the BDS region is weakened by IGSO4 and GEO5 when the threshold is 2.60.Taking the BDS satellite during normal operation of the GDOP region average maximum value(S=2.60)as the system availability threshold,the system availability is decreased by 1.79%and 32.63%.When the threshold is 2S(5.20),3S(7.80),4S(10.4),5S(13.0),the availability of the system can reach 100%.After the failure of GEO as a whole,BDS high-precision positioning can still be partially available,but the availability of BDS system is greatly limited after the failure of IGSO.Therefore,to increase the on-orbit backup of the satellite,we need to focus on the GEO5,IGSO4 satellite backup,and the appropriate increase in the number of IGSO satellites.