为解决传统锁相环(PLL)在高动态环境下对全球定位系统(GPS)信号的跟踪精度问题,将自适应渐消滤波和二级卡尔曼滤波相结合研究了一种新的自适应二级卡尔曼滤波算法,并且提出了一种利用新息协方差计算渐消因子的方法,通过自适应渐消因子在线调节误差协方差矩阵补偿不完整信息的影响,使滤波器在系统模型不完整或者噪声统计特性不准确时仍接近最优。基于自适应二级卡尔曼滤波算法提出了一种高动态GPS载波跟踪环的设计方案。仿真结果表明,提出的方案较传统PLL的跟踪精度有显著提高,频率跟踪精度提高到9.28Hz。
In order to solve the accuracy problem that the traditional phase locked loop (PLL) tracks the global positioning system(GPS) signal in the high dynamic environment , combining the adaptive fading Kalman filter with the two- stage Kalman filter, this article studies a new adaptive two-stage Kalman fiher is studied in this paper, and proposes a method of calculating the fading factor according to innovation covariance is proposed to compensate the effect of incomplete information by on-line adjusting of the error covarianee through the fading factor, and ensure that the filter is optimal when the information of the system model and noise statistics is incomplete. A structure of high dynamic GPS carrier tracking loop is proposed based on adaptive two-stage kalman filter. The simulation results show that this scheme have a obvious improvement of tracking accuracy compared with the traditional PLL, and the frequency tracking accuracy is improved to 9.28Hz.