基于北斗卫星载波相位平滑伪距的列车定位方法

随着我国北斗卫星导航系统的建设,北斗卫星已逐步具备应用于列车定位的能力。列车在铁路线上存在轨道占用区分的需求,北斗民用伪距定位对并行股道占用情况难以精确定位识别。采用北斗实时载波相位定位精度高,但需近距离基准站的差分信号和模糊度解算,不利于大范围内的实时应用。因此,本文结合北斗卫星伪距的无模糊度和载波相位的高精度特点,提出一种基于北斗载波相位平滑伪距的列车定位方法。该方法首先利用北斗组合相位伪距法探测与修复载波数据周跳,并采用修复后的载波相位数据平滑伪距。文中推导北斗载波相位平滑伪距的原理,分析不同平滑方法的特性和对应的噪声检验公式。采用实测数据计算两种平滑方式得到的结果表明:本文提出的方法能够有效快速探测与修复周跳,平滑伪距精度优于0.2m,满足北斗导航系统在铁路列车定位中的精度要求。

Method of Train Positioning Based on Beidou Carrier Phase Smoothing Code

Along with development of the Beidou satellite navigation system in China,Beidou has gradually possessed the ability to be applied in train positioning.Train positioning requires track occupancy recognition,however,it is hard for Beidou to accurately position and recognize occupation of parallel tracks by civil pseudo-range positioning.Carrier phase positioning of Beidou has higher positioning accuracy,but its extensive and real-time application is limited because of the needs for differential signals from near reference stations and phase ambiguity resolution.In this paper,combining the advantages of non-ambiguity pseudo-range and high precision of carrier phase,the train positioning method was proposed on the basis of carrier phase smoothing pseudo-range.The algorithm of combinatorial phase and pseudo-range was employed to detect and repair cycle slips.The repaired carrier phase data were utilized to smooth pseudo-range.The principle of carrier phase smoothing pseudo-range was interpreted.The characteristics of different smoothing methods and corresponding noise testing equations were analyzed.The results of the two smoothing methods calculated with measured data indicate that the proposed train positioning method can detect and repair cycle slips effectively and quickly and achieve the Beidou pseudo-range accuracy better than 0.2 m,thus satisfying the requirements for accuracy of train positioning.