载波相位平滑时间常数对GBAS精度增强的影响

Influence of carrier phase smoothing time constant on GBAS accuracy enhancement

陆基增强系统(GBAS)是利用载波相位平滑伪距差分修正实现对导航辅助定位的.其中,平滑时间常数是影响载波相位平滑伪距精度的关键参数.本文分析研究了不同平滑时间下电离层时间梯度和空间梯度对Hatch滤波的影响.在结合电离层时空梯度和多径效应引起的滤波总误差方差的基础上,推导出自适应的最优平滑时间常数.分别对GBAS静态和动态两种环境下的定位误差进行实验,实验结果表明,采用本文推导出的自适应平滑时间常数降低了GBAS伪距测量误差,从而使定位精度得到增强.

The Ground Based Augmentation System(GBAS) uses carrier phase smoothing pseudorange differential correction to achieve navigation aided positioning. The smoothing time constant is a key parameter affecting the accuracy of carrier phase smoothing pseudorange. To analyze the effects of ionospheric time gradient and spatial gradient on Hatch filtering under different smoothing times. Based on the analysis of the total error variance of the filtering caused by the ionospheric time-space gradient and multipath effect, the adaptive optimal smoothing time constant is derived. The positioning errors of GBAS static and dynamic environments are tested respectively. The experimental results show that the adaptive optimal smoothing time constant reduces the GBAS pseudorange measurement error, which enhances the positioning accuracy.