基于虚拟观测值后验方差估计的整周模糊度快速固定方法

Fast GPS Ambiguity Resolution with Variance Component Estimation Based on Virtual Observation

利用历元间坐标差信息可以改善模糊度在航快速解算过程中法方程的病态性,从而加快模糊度固定的速度。但是该方法涉及两类不同的观测值(载波相位双差观测值和由历元间坐标差信息导出的虚拟观测值),为合理利用历元间坐标差信息,需要确定这两类观测值的权比。利用方差分量估计方法调节两类观测值的权比,提高模糊度浮点解的精度,从而进一步加快模糊度固定。实验结果表明,采用Helmert方差分量估计方法调整两类观测值的权比,可以进一步提高模糊度在航解算的效率,增强模糊度固定的可靠性。

Epoch-differenced coordinate information between neighboring epochs can be used to mitigate the ill-condition of the normal equation in ambiguity resolution on-the-fly.Consequently,the convergence time of ambiguity will be shortened.However,the method involves two different types of measurements：first,double-differenced carrier phase measurements,and second,virtual measurements derived by coordinate difference information between neighboring epochs.With the aims of improving the accuracy of the double-difference integer ambiguity float estimates and accelerating ambiguity fixing,this paper uses variance component estimation to regulate the weight ratio of the two types of measurements.Experimental results show that both the efficiency and reliability of ambiguity resolution on-the-fly can be further enhanced with Helmert variance component estimation adopted to adjust the weight matrix of virtual observations derived by epoch-differenced coordinate.