窄巷FCB估计方法改进及时变特性分析

窄巷波长相对较短,受观测数据质量和未模型化误差的影响较大,导致参考站计算的窄巷FCB估值的互差较大,窄巷FCB稳定性较差。针对窄巷FCB估值出现较大偏差的参考站,本文提出了基于抗差初值的窄巷FCB抗差估计方法,该方法取当前历元所有参考站窄巷FCB估值的中位数作为抗差初值,采用IGGⅢ方案降低了有偏差的窄巷FCB估值的权比。采用IGS全球跟踪站网的数据进行验证,改进的方法提高了窄巷FCB的精度和稳定性,采用每天估计的一组卫星端的窄巷FCB即可满足窄巷模糊度固定的精度要求。同时,采用本文改进方法估计的窄巷FCB,可以提高用户端仿动态单天解的窄巷模糊度固定成功率和定位精度。

Improvement of Narrow-lane Fractional Cycle Bias Estimation and Analysis of Its Time-varying Property

The length of narrow-lane FCB is short,and it's seriously influenced by the quality of observation data and inaccurate models,narrow-lane FCB estimates of different reference station are significantly biased,thus the stability is relatively poor.Aiming at those biased narrow-lane FCB estimates,narrow-lane FCB robust estimation method based on robust initial value is proposed,the median of narrow-lane FCB estimates of all reference stations at current epoch is utilized as the robust initial value,and IGGⅢ scheme is applied to decrease the contribution of biased narrow-lane FCB estimates.Data from IGS global tracking stations are used in the experiment,the accuracy and stability of narrow-lane FCB are improved,the need of narrow-lane ambiguity fixing can be satisfied based on a group of daily estimated satellite narrow-lane FCB.Meanwhile,the success rate of narrow-lane ambiguity fixing and imitated dynamic positioning accuracy are improved.