三阶卡尔曼滤波数字锁频环设计及性能分析

提出了一种基于三维卡尔曼滤波的三阶数字锁频环设计方法,并将该锁频环用于高动态GPS信号的载波跟踪。推导了卡尔曼滤波与数字锁频环之间的等效关系,给出了基于该方法设计的锁频环的等效噪声带宽闭式解,分析了环路的暂态性能和稳态性能。以暂态带宽和均方根频率跟踪误差为性能指标,对基于该方法设计的锁频环和固定增益的数字锁频环进行了仿真对比。结果表明,在具有相同稳态带宽的情况下,两种环路具有可比拟的动态和静态跟踪误差,但基于该方法设计的环路具有较高的初始捕获带宽,环路收敛时间大大降低。

Design and Performance Analysis of 3rd Order Kalman Filter Digital Frequency-Locked Loop

A three-dimensional Kalman filter based digital frequency-locked loop design approach is proposed for the carrier tracking of high dynamic global positioning system signals. The equivalence between Kalman filer and digital frequency-locked loop is derived. The transient-state and steady-state loop performance are analyzed. The simulation results show that the Kalman filter based digital frequency locked loop (DFLL) has much wider bandwidth in the transient-state than the fixed-gain DFLL while both have the same steady-state bandwidth, and the convergence time decreases a lot.