高动态条件下改进的EKF载波跟踪环路

A modified carrier tracking loop using an extended Kalman filter in high dynamic conditions

针对高动态环境下扩展Kalman滤波器跟踪环路的性能,分析了该跟踪环路的带宽特性,建立了环路带宽的数学模型.在此基础上,提出了一种改进的扩展Kalman滤波器跟踪环路.在不同条件下对2种算法的环路带宽特性做了分析比较,结果表明改进算法的环路带宽比NASA提出的常规算法显著减小.在相对加加速度为100 g/s的高动态条件下,对2种算法的跟踪性能进行了仿真,结果显示,与常规算法相比,改进算法的频率误差和失锁概率都明显降低,跟踪灵敏度提高1.3 dB.

The bandwidth characteristics of an extended Kalman filter were analyzed in order to study the filter＇s performance in tracking high dynamic signals,and a mathematic model was also established.According to the analysis,a modified tracking loop was proposed.The bandwidth characteristics of both algorithms were analyzed under various conditions,and the results show that the bandwidth of the modified method is much smaller than that of routine method from NASA.Both algorithms were simulated with high dynamic global navigation satellite system（GNSS） signals whose relative jerk achieves 100 g/s.Compared with a routine algorithm,the frequency error and probability of a loss-of-lock of novel algorithm are all markedly reduced,and the tracking sensitivity is increased by 1.3 dB.