BDS卫星短时差分码偏差估计与分析

Estimation and analysis of BDS satellites short-time DCB

现有的差分码偏差(differential code bias,DCB)产品和常用的DCB估计方法均是将DCB视为1 d中的常量参数,忽略了DCB在1 d中的短时变化。为了分析北斗卫星导航系统(BeiDou Navigation Satellite System,BDS)卫星DCB短时变化特性,文章首先采用最小二乘和Tikhonov正则化方法同步估算各个历元时刻下的电离层参数和DCB参数,然后分析卫星DCB短时序列的精度和稳定性,并利用谱分析方法对短时DCB的周期性进行分析,建立模型来拟合短时DCB变化,最后通过实验探讨短时DCB序列改正对标准单点定位(standard point positioning,SPP)的影响。实验结果表明:在SPP中,施加DCB改正可以提高定位精度,施加中国科学院(Chinese Academy of Sciences,CAS)产品改正或短时DCB改正,定位精度提升都在40%以上;在不同测站上施加短时DCB改正和CAS产品改正,SPP定位精度各有优劣,两者差异在cm级,改正效果大致相当。

The existing differential code bias(DCB)products and common DCB estimation methods regard DCB as a constant parameter in a day,and ignore the short-time variation of DCB in a day.In order to analyze the short-time variation characteristics of BeiDou Navigation Satellite System(BDS)satellites DCB,firstly,the ionospheric parameters and the DCB parameters of each epoch were estimated synchronously using least square and Tikhonov regularization methods.Secondly,the accuracy and stability of satellites DCB short-time series were analyzed.Then,the periodicity of short-time DCB was determined by spectral analysis,and the short-time DCB variation was modeled.Finally,the influence of short-time DCB sequence correction on standard point positioning(SPP)was discussed through experiments.The results showed that in SPP,DCB correction could improve the positioning accuracy.Both Chinese Academy of Sciences(CAS)product correction and short-time DCB correction improved the positioning accuracy by more than 40%.Both short-time DCB correction and CAS product correction have their own advantages and disadvantages in SPP positioning accuracy at different stations.The difference is at the centimeter level,and the improvement effect is roughly the same.