不同环境下GNSS互操作信号动态性能分析

A comparative analysis on kinematic performance of GNSS interoperability signals under different environments

针对全球导航卫星系统(GNSS)动态应用过程中,观测环境会随着载体运动发生变化,引起卫星可见数、卫星信号强度和观测数据质量的变化,影响用户端导航定位性能的问题,提出一种不同环境下GNSS互操作信号动态性能分析方法:以车载导航为例,抽取开阔路段、半遮挡路段和遮挡路段,从GNSS数据接收能力、数据质量和导航定位性能3个方面,分析不同环境下GNSS互操作信号B1C/L1/E1和B2a/L5/E5a动态性能。结果表明:1)GNSS数据接收能力。3种环境下北斗三号卫星导航系统(BDS-3)的可观测卫星数大于9颗且PDOP值小于2.4,明显优于全球定位系统(GPS)和伽利略卫星导航系统(Galileo);随着环境遮挡严重,GNSS数据完整率明显下降,数据中断率增加。2)GNSS数据质量。观测环境变化对于信号载噪比和多路径存在明显影响;不同环境下B1C载噪比均值高于41 dB·Hz,且优于L1和E1频率,B2a频率载噪比值均高于43 dB·Hz,但略低于L5频率;BDS-3多路径效应均值优于40 cm,比GPS和Galileo稍差,其中B2a优于B1C。零基线噪声中B1C表现优于E1和L1,其中伪距观测值中L5频率较优,但在遮挡环境B2a优于L5;而载波相位中B1C频率表现最好。3)导航定位性能。不同环境下标准单点定位(SPP)中,L1与B2a精度较优;双频精密单点定位(PPP)中BDS-3 B1C/B2a精度最优,遮挡路段解算精度相较于GPS和Galileo分别提高了38%和10%。

Aiming at the problem that in the process of dynamic application of global navigation satellite system(GNSS),the observation environment will change with the movement of the carrier,which will cause changes in satellite visibility,satellite signal strength and observation data quality,thus affecting the navigation and positioning performance of the client,this paper proposed a kinematic performance analysis method for GNSS interoperable signals under different environments:taking vehicle navigation as an example,three types of road scenarios were selected to analyze the dynamic performance of GNSS interoperable signals B1C/L1/E1 frequencies and B2a/L5/E5a frequencies under different environments,which include the open road scenario,semi-obstructed road scenario and obscured scenario.Results showed that:1)For GNSS data reception capability.The number of observable satellites of the BeiDou-3 navigation satellite system(BDS-3)in the three environments would be more than 9,and the PDOP value less than 2.4,which could be significantly better than that of the global positioning system(GPS)and Galileo navigation satellite system(Galileo);moreover,with the serious occlusion of the environment,the GNSS data integrity rate would decrease sharply while the data outage rate would increase.2)For GNSS data quality.The variation of the observed environment would have obvious influence on the signal-to-noise ratio and multi-path;under different environments,the mean load of signal-to-noise ratio of B1C would be higher than 41 dB·Hz,better than that of L1 and E1,and the load of signal-to-noise ratio of B2a would be higher than 43 dB·Hz,but slightly lower than that of L5;the mean multi-path effect of BDS-3 would be better than 40 cm,slightly worse than GPS and Galileo,where B2a could be better than B1C.Moreover,the performance of B1C would be better than that of E1 and L1 in the zero-base noise,where the frequency of L5 could be better in the pseudo-range observation,but B2a could be better than L5 in the occlusion environment;while the carrier phase B1C frequency would perform best.3)For navigation and positioning performance.In standard single-point positioning(SPP)under different environments,L1 and B2a frequency would have better accuracy;meanwhile,BDS-3 would have the best accuracy in dual-frequency precision point positioning(PPP),and the calculation accuracy of the occluded sections could be improved by 38%and 10%compared with GPS and Galileo,respectively.