北斗三号卫星导航信号接收机端伪距偏差建模与验证

Receiver pseudorange biases of BDS-3 satellite navigation signal:modeling and validation

接收机端伪距偏差是指非理想的卫星导航信号在接收机前端带宽和相关器间隔不同时产生的伪距测量系统性偏差。研究表明,北斗二号、GPS和Galileo系统均存在与接收机类型相关的伪距偏差,影响基于混合类型接收机站网的精密数据处理。本文基于iGMAS网和MGEX网观测数据,采用MW组合、伪距残差和伪距无几何距离无电离层组合3种方法分析北斗三号接收机端伪距偏差特性。试验结果表明,北斗三号同样存在与接收机类型相关的伪距偏差,且无电离层组合的伪距偏差可以达到6 ns。根据偏差特性,按接收机类型建立了8类伪距偏差改正模型。将上述模型应用于卫星差分码偏差(DCB)估计与单频伪距单点定位,结果表明,模型改正后可以显著提升不同接收机类型估计的卫星DCB一致性,其中基于iGMAS网和MGEX网两个不同接收机站网估计得到的北斗三号C2I-C6I、C1P-C5P和C2I-C7D DCB差值分别平均降低了91.6%、64.7%和71.9%;模型改正后单频伪距单点定位水平方向和高程方向精度分别提升了13.9%和11.0%。

Receiver pseudorange biases are systematic pseudorange biases caused by non-ideal satellite navigation signals among different bandwidths and correlator spaces.Studies indicate that BDS-2,GPS and Galileo are all influenced by receiver-related pseudorange biases,which will affect the precise data processing among inhomogeneous receivers.In this paper,we use three observation combinations,including Melbourne-Wübbena(MW),ionosphere-free(IF)and pseudorange ionosphere-and geometry-free(IFGF)combinations,to analyze the characteristics of BDS-3 pseudorange biases based on International GNSS Monitoring and Assessment System(iGMAS)and Multi-GNSS EXperiment(MGEX)observations.The results show that there are receiver-related pseudorange biases for BDS-3 and the IF combination biases can reach up to 6 ns.According to the characteristics of BDS-3 pseudorange biases,eight groups of corrections are estimated and validated by differential code bias(DCB)estimation and single-frequency single point positioning(SF-SPP).The results indicate that the consistency of BDS-3 satellite DCB estimated by different receiver groups can be significantly improved when corrections are used.For example,the difference of C2I-C6I、C1P-C5P and C2I-C7D DCB estimated by iGMAS and MGEX receivers decrease by 91.6%、64.7%and 71.9%,respectively.Moreover,after correcting the pseudorange bias,the accuracy of SF-SPP are improved by 13.9%and 11.0%in vertical and horizontal components,respectively.