高动态GPS载波跟踪组合环路控制策略

High Dynamic Control Strategy of Combined GPS Carrier Tracking Loop

在保证跟踪精度和动态适应性的前提下,传统GPS复合跟踪环存在环路切换频繁、滤波不连续等现象。针对该问题,提出了一种基于频率牵引和自适应加权技术的载波跟踪组合环路控制策略。该策略先通过频率牵引算法将捕获后的频差牵引到较小的范围内,然后利用带有跟踪状态判决算法来自适应调节锁频环和锁相环主导作用的复合环路对信号进行跟踪。仿真结果表明:采用文中提出的高动态GPS载波跟踪组合环路控制策略,接收机能在最大加速度150 g,加加速度50 g/s的动态指标下正常工作。

In order to ensure the accuracy of the tracking and dynamic adaptability,traditional GPS composite tracking loop has the problems of frequent loop switching and filtering discontinuous phenomena.To solve the problem,a combination of carrier tracking loop control strategy that based on frequency pulling and adaptive weighting techniques was presented in this paper.Firstly,the frequency difference after capture was pulled to a smaller range by frequency pulling algorithm,then the signal was tracked by composite loop ,which used track-ing state decision algorithm to adaptive FLL and PLL leading role .Simulation results showed that the proposed GPS carrier tracking algorithm could work normally with the dynamic indexes of acceleration up to 150 g and jerk up to 50 g/s.