一种非差非组合PPP估计卫星DCB的改进算法  

An Enhanced Estimation Algorithm for Satellite DCB Based on the Undifferenced and Uncombined PPP

作　　者：章繁 柴洪洲[1] 王敏[1] ZHANG Fan;CHAI Hongzhou;WANG Min(School of Surveying and Mapping,Information Engineering University,62 Kexue Road,Zhengzhou 450001,China)

机构地区：[1]信息工程大学地理空间信息学院,郑州市450001

出　　处：《大地测量与地球动力学》2023年第8期780-785,860,共7页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(42074014)。

摘　　要：提出一种基于非差非组合PPP估计卫星DCB的改进算法,该算法同时利用非差非组合PPP和载波相位平滑伪距提取斜向电离层观测值,基于单站电离层建模分离电离层观测值中的垂向电离层延迟,并假设卫星DCB之和为0以消除秩亏,最后基于加权最小二乘平差方法同时估计DCB和电离层延迟等参数。由于两类电离层观测值的精度存在差异,随机模型会出现权比失调问题。对此,引入方差分量估计方法,基于方差分量估计的残差向量,利用后验估计的方式迭代调整两类电离层观测量权比,从而达到优化随机模型的目的。利用MGEX测站数据验证算法的有效性,结果表明,本文方法卫星DCB估值精度为0.32 ns,相比传统载波相位平滑伪距方法和等权比融合两类观测值方法分别提升52.24%和43.86%。This paper proposes an enhanced algorithm to estimate satellite DCB based on undifferenced and uncombined precise point positioning(UPPP).Our method uses UPPP and geometry-free linear combination of phase-smoothed range to extract slant ionosphere.Then we establish models to separate vertical ionospheric delay from ionospheric observations based on each single station,and assume that the sum of satellite DCBs is 0 to eliminate rank deficit.At last,DCBs and ionospheric delay are estimated simultaneously based on the weighted least squares adjustment method.However,because of the difference in the accuracy of the two types of ionospheric observations,the stochastic model suffers from the problem of weight inaccuracy.To overcome this problem,we introduce a variance component estimation method.The method iteratively adjusts the weight ratio of the two types of ionospheric observations based on the residual information,constructing a more reasonable stochastic model.The effectiveness of the algorithm is validated by observations from MGEX stations.Results show that,the satellite DCB estimation accuracy of the proposed method is 0.32 ns,which is 52.24%and 43.86%higher than that of the traditional geometry-free linear combination of phase-smoothed range method and the equal weight fusion model,respectively.

关 键 词：方差分量估计 非差非组合PPP 斜向电离层 载波相位平滑伪距 DCB 

分 类 号：P228[天文地球—大地测量学与测量工程]