三颗星的AGNSS增强定位方法研究

为了提高辅助全球导航卫星系统（AGNSS）的定位性能，实现用户在捕获卫星数不满足解算条件下进行有效定位，论文对只有三颗可见星情况下的定位方法进行了研究。研究中采用AGNSS定位系统结构，以加快卫星捕获并提供辅助数据，通过两次观测数据的组合完成定位解算，并分析无卫星重复、有卫星重复以及两次观测间隔时长等因素对精度因子、定位性能以及置信度的影响。通过定位验证可知，随着两次观测间隔时长的增加，定位性能越来越好。当间隔时长为2min时，无卫星重复时的定位精度为2.22m，一颗星重复时为3.21m，两颗星重复时为16.76m，三颗星完全重复时为38.72m，其精度完全可以满足用户对位置的需求，增强了AGNSS定位性能。

Three Satellites Enhanced Positioning Method for AGNSS

A position method was studied under the condition of only three visible satellites in this paper in order to improve the positioning performance of assisted Global Navigation Satellite System (ANGSS) and to implement effective positioning with imperfect positioning condition. In the research, AGNSS positioning structure was used to capture satellite more quickly and to provide assisted data. The positioning results were calculated by the combination of double-observation data, then the influence of no overlapped satellites, overlapped satellites and the length of double-observation interval time on the dilution of precision (DOP), positioning performance and confidence were analyzed. The positioning results were showed that the positioning performance was getting better and better with the interval of two observations increasing. When the length of interval time was 2min, the positioning accuracy was up to 2.22m under the condition of no overlapped satellites, and the accuracy was 3.21m under overlapped one satellite, and the accuracy was 16.76m under overlapped two satellites, and the accuracy was 38.72m. The positioning accuracy could meet the needs of the users for position, and the AGNSS positioning performance was enhanced.