摘要
针对无线电导航系统中全数字伪码跟踪环路进行了研究,分析了直接扩频序列的自相关特性,给出了伪码鉴相特性曲线,建立了伪码跟踪环路模型,运用不动点理论对鉴相特性曲线中的非线性区域跟踪性能展开了研究,得到了二阶全数字超前-滞后环的环路特性,给出了跟踪环路稳定的参数设计条件和环路最佳收敛时的参数要求,并对不同参数下的伪码跟踪环路性能进行了仿真。仿真结果表明:只有当伪码相位初始误差在收敛域时,跟踪环路才能最终稳定于零,而收敛域的大小则随着环路增益的增大而增大。
The performance of digital PN （pseudonoise） code tracking loop which is used in the spread spectrum navigation system was analyzed by the fixed-point theory in this paper. Though analyzing the correlation character of the direct spread sequence, the phase-discrimination curve was given and then the model of PN code tracking loop was built up. The non-linear area in phase-discrimination curve was analyzed though a non-linear method-the fixed-point theory, then the loop tracking performance of the second-order digital delay lock loop and the design condition of the parameters in the loop were obtained. Finally the influence of the parameters to the tracking performance were simulated, the simulation result shows that only the phase error located in the convergence domain the phase loop can track the code phase precisely, and the convergence domain is decided by the gain of phase tracking loop.
出处
《电机与控制学报》
EI
CSCD
北大核心
2008年第6期701-705,711,共6页
Electric Machines and Control
基金
国家自然科学基金(60704018)
关键词
不动点理论
伪码跟踪
鉴相特性曲线
全数字超前-滞后环
the fixed-point theory
PN code tracking
phase-discrimination carve
digital delay lock loop
