改进的GPS/BDS的RTK定位性能分析

The improved of the analysis of the RTK positioning performance based on GPS/BDS

针对多路径误差作为短基线GNSS定位的主要误差来源,不能在传统双差模型中有效消除的问题,该文基于小波分解和重构,提出了一种对伪距和载波相位观测值中多路径误差有效提取和剔除的算法,探讨剔除后GPS/BDS双系统的RTK定位精度和可靠性。结果表明,伪距多路径误差和载波相位多路径误差量级分别为米级和厘米级,主要集中在低频滤波中,且提取后的残余随机噪声趋于稳定。此算法能较好地剔除和提取多路径误差,提高整周模糊度解算速度,达到理想的滤波效果,且通过迭代扩展的卡尔曼滤波处理后,坐标离散更小,X、Y、Z外符合精度均达到厘米级。

The Multipath error is the main error source in GNSS short baseline positioning applications,and can＇t be effectively eliminated in traditional double-difference model.According to the shortcomings of the algorithm,the article which is based on wavelet decomposition and reconstruction comes up with the extraction and eliminate effectively the multipath error that lies in the pseudorange and carrier phase observation algorithm.We discuss the RTK of the GPS and BDS dual system position accuracy and reliability.The analysis indicates that the pseudorange multipath error and the carrier phase multipath error scale are m-level and cm-level respectively,which are mainly concentrated in low-frequency filtering,and extraction of residual random noise tends to be stable.This algorithm can eliminate and extracte multipath error effectively,and improve the integer ambiguity estimating velocity,and achieve the ideal filter.In this way,we use the iterated extended kalman filter in dealing with the data,the result shows that the degree of dispersion coordinates becomes smaller,the X,Y and Z coordinate outer precision can achieve cm-level.