基于CIT技术的广域增强系统电离层延迟修正算法

提出了一种基于电离层层析成像(CIT)技术的广域增强系统(WAAS)电离层延迟 修正算法. 该算法利用模式基函数与截断奇异值分解正则化组合的方式, 实现WAAS单频用户的电离层延迟误差修正. 基于中国区域23个广域基准站 和10个用户站的仿真结果分析表明, 传统的网格算法和基于CIT技术的电离 层延迟修正算法的电离层延迟修正精度与太阳活动、昼夜变化及地磁纬度 之间均存在明显的相关性. 基于CIT技术的电离层延迟修正算法精度优于网格算法, CIT算法的平均误差与标准差相比网格算法均有较大幅度的下降.

CIT-based Correction Algorithm for the Ionospheric Delay in Wide Area Augmentation System

Ionospheric delay is one of the most important error sources in satellite navigation and positioning, many methods were adopted to mitigate the ionospheric delay for high precision navigation applications, such as local area differential GPS, wide area differential GPS, wide area augmentation differential GPS and Wide Area Augmentation System (WAAS). A new algorithm based on Computerized Ionospheric Tomography (CIT) for ionospheric delay correction in WAAS was proposed in this paper. The error of ionospheric delay can be corrected by the orthogonal combination of model-based function and Truncated Singular Value Decomposition (TSVD) for single frequency user in WAAS. The simulation results of 23 wide-area reference stations and 10 user stations in China show that the precision of ionospheric delay correction based on traditional grid-based algorithm and CIT-based algorithm have evident correlation with solar activities, local time and magnetic latitude as well. However, the performance of CIT-based algorithm is much better than that of grid-based algorithm. Both the mean error and standard deviation of CIT-based algorithm are far less than grid-based algorithm.