用加权几何精度因子选星的GPS抗多径定位方法

Multipath Mitigation Positioning Technique with Weighted GDOP in Selecting GPS Satellites

在 GPS (Global positioning system )中普遍用几何精度因子 (Geometric dilution ofprecision,GDOP)来选星 ,但对近距差分 GPS,多径干扰已变成了主要误差源 ,传统的 GDOP值选星不是最佳的。为减小多径误差 ,文中提出了一种新的加权 GDOP值选星方法。在仿真验证过程中 ,分析了多径的几何传播机理 ,并考虑了抗多径天线的抑制效应。仿真结果表明 ,用加权 GDOP选星可以使多径引入的定位误差减小到 1/3以下。

In global positioning system (GPS), geometric dilution of precision (GDOP) is a popular measurement to select satellites. But in the short baseline differential GPS, multipath becomes a major error source, the traditional measurement isn′t most optimal. To reduce the multipath error, a new weighted geometric dilution of precision is proposed. The loop combined code phase tracking delay locked loop(DLL) with carrier synchronization phase locked loop(PLL)in the digital GPS receiver is studied to test and verify the positioning technique. The influence on the choke ring antenna and the geometrics of multipath propagation are also analyzed. Simulational results show that the positioning error may be reduced below 1/3 if the weighted GDOP is used.