基于自适应卡尔曼滤波的GNSS矢量锁定环路

GNSS vector lock loop based on adaptive Kalman filter

摘要:

为了减小卫星信号信噪比变化对全球导航卫星系统(GNSS)接收机当中矢量锁定环路(VLL)的不良影响,使用一种基于新息的自适应卡尔曼滤波方法对其改进,以实现对VLL滤波器观测噪声协方差矩阵的实时调整．使用后处理软件全球定位系统(GPS)接收机处理信号发生器产生的中频数据以对提出的方法进行验证．实验结果表明,相对于传统标量环路(SLL),基于自适应卡尔曼滤波的VLL可以在信噪比降低甚至可见卫星数目不足的环境下工作,其载波频率跟踪精度及导航定位解精度均优于固定参数矢量环路和传统标量环路．

Abstract:

To mitigate the negative impact of varying satellite signal-to-noise ratio (SNR) on the vector lock loop (VLL) in a Global Navigation Satellite System (GNSS) receiver, an innovation based adaptive Kalman filter is employed to real-time adjust VLL measurement noise covariance matrix. Intermediate frequency data from a Global Positioning System (GPS) signal generator are post-processed using a software GPS receiver to verify the proposed method. The experimental result shows that VLL with the proposed adaptive Kalman filter outperforms under lower SNR conditions or with even insufficient amount of visible satellites comparing with the conventional scalar lock loop (SLL). Both carrier frequency tracking results and navigation solutions from the proposed method are more accurate than those from either fixed-parameter VLL or conventional SLL.