一种顾及先验约束的窄巷FCB估计方法

A narrow lane FCB estimation method considering prior constraints

精密单点定位(PPP)技术由于作业灵活,目前在多领域得到了广泛的应用,其中整周模糊度固定是精密单点定位的核心问题。由于北斗三号全球卫星导航系统(BDS-3)的测站分布大多数集中在亚太区域,因此BDS-3的窄巷小数周偏差(FCB)受观测环境和观测条件的影响,各时段估计值差异较大,窄巷FCB的估计精度严重制约了BDS-3精密单点定位的整周模糊度固定。针对此问题,本文提出了采用最小方差估计算法,加入先验信息估计窄巷FCB的方法。首先对各观测站的观测数据进行粗差探测与隔离,在处理“干净”的数据的基础上,依据先验方差和均值进行最小方差估计,最后采用亚太地区38个观测站数据进行验证。试验结果表明,新方法估计的窄巷FCB月稳定性在0.2周以内,利用估计的窄巷FCB在进行BDS-3精密单点定位时,静态条件下固定率可达95.1%,定位精度在东向、北向和天向3个方向的均方根误差(RMS)分别为1.1、1.3和3.9 cm。

Navigation precise point positioning(PPP)technology has been widely used in many fields because of its flexible operation,and the fix of ambiguity is the core problem of PPP.As the BeiDou-3 navigation satellite system(BDS-3)stations are mostly concentrated in the asia-pacific region,therefore,the narrow lane Fractional Cycle Bias(FCB)of the new system signal broadcast by BDS-3 is affected by the observation environment and observation conditions,and the estimated values of each time period are quite different,therefore,the estimation accuracy of FCB in narrow roadways seriously restricts the whole-cycle ambiguity of BDS-3 precise point positioning.In order to solve this problem,a new FCB estimation method based on minimum variance estimation and prior information is proposed.Firstly,gross error detection and isolation are performed on the observed data of each station,and minimum variance estimation is made according to prior variance and mean on the basis of processing“Clean”data.Finally,the data from 38 observatories in asia-pacific region are used for verification.The experimental results show that the monthly stability of FCB in the new system is less than 0.2 weeks,and the fixed rate of FCB in the new system can reach 95.1%under static condition when BDS-3 precise point positioning is performed,the root mean square errors(root mean square rms)of the positioning accuracy in the east,north and sky directions were 1.1,1.3 and 3.9 cm.