基于高度角加权的伪卫星定位线性化误差评估方法

A Linearization Error Evaluation Method of Pseudolite Positioning Based on Weighted Elevation Angle

摘要: 与其他基于测距进行定位解算的导航系统(如GPS)一样，伪卫星定位系统观测模型在本质上是非线性的，对观测模型进行线性化对于大部分定位算法是一个必不可少的过程，而与GPS等卫星导航系统不同的是，伪卫星距离用户较近，其模型线性化时产生的误差不能被忽略，否则会导致定位解算可能无法正确收敛。针对此问题，本文精确地给出了线性化误差的边界值，并提出了判别线性化误差对定位精度影响的简化方法，根据此方法分析了不同伪卫星的星座布局对伪卫星系统线性化误差的影响。通过仿真对所提出的伪卫星的线性化误差评估的方法进行了验证。结果表明，当伪卫星系统满足判定条件时，迭代结果一定会收敛，而不满足时，则不一定收敛。

Abstract: Like the other navigation systems which are calculating positioning based on ranging, such as GPS, the observation model of pseudolite positioning system is essentially nonlinear. For most posi-tioning systems, linearization of the observation model is an essential process. Since the distances between the user and pseudolites are close compared with GPS and other satellite navigation sys-tems, the linearization error of the model cannot be ignored. Otherwise it may lead to incorrect convergence of the positioning solution. To solve this problem, this paper gives a precise boundary value of the linearization error. What’s more, it also gives a simplified method to judge the impact of the linearization on the positioning accuracy, based on which, impacts of different pseudolite constellation layouts on linearization error are analyzed. And then, it verifies the proposed assessment method of the linearization error of pseudolites by simulation. The results show that when the pseudolite systems satisfy the condition, results of the iteration will converge, otherwise, they are not necessarily converge.