非等量采样伪码跟踪环建模分析

Modeling and analysis of pseudo-code tracking loop with non-commensurate sampling

针对基带非等量采样伪码跟踪环参数优化设计问题,给出了非等量采样伪码跟踪环的MATLAB建模方法与部分代码。结合1 023 chip平衡Gold码延迟抖动跟踪环路模型与归一化点积功率型鉴相算法,给出了非等量伪码采样实现与环路仿真流程。同时,给出其环路滤波器误差输出曲线和环路再生伪码与接收信号中伪码的互相关函数曲线。仿真结果表明:在相同激励信号条件下,当采样频率小于4倍伪码速率时,该采样频率大约在2 k Hz的变化范围内,环路的伪码互相关函数曲线仍具有较好的对称性能。

A new analysis method with regard to parametric optimal design problems in a pseudo-code non-commensurate sampling loop is proposed,in which the simulation model of the gold-code tracking loop in MATLAB modeling and partial codes are established. Using the model of the delay-lock-loop and the normal-ized-dot-product phase-detector,the realization of a non-commensurate sampling pseudo-code tracking loop is given. Simulataneously,the function curve relating to loop filter error output and loop renewed pseudo-code as well as the pseudo-code in receiving signals is also developed. Simulation results show that under the same in-put signal,and when sampling frequency is below fourfold pseudo-code speed,and sampling range is within 2 kHz,the correlation function curve of loop pseudo-code is of better symmetry.