GPS接收机数字码跟踪环性能研究

Performance analysis of digital delay-locked loop for GPS receiver

从数字码跟踪环的角度研究了高动态体制下GPS接收机性能 ,对伪码捕获和跟踪过程建立了数学模型 ;推导出伪码捕获的检测概率和虚警概率 ,提出改进的双Dwell搜索方法 ;对高阶DDLL的动态跟踪性能及输入随机噪声影响进行了定量分析。通过MATLAB及Simulink动态仿真结果表明 ,双Dwell搜索方法能显著缩短平均捕获时间 ;可根据具体应用环境 ,选择不同的环路参数 ,以优化码跟踪环的特性。

The paper gives out mathematical modeling of the digital PRN code acquisition and tracking process,derives the expressions of the detection and false-alarm probabilities, presents the improved double_dwell search strategy ,analyzes the dynamic tracking performance and influence of input noise mathematically. The results of analysis show double dwell search strategy could reduce mean time of acquisition dramatically.Different loop parameters should be selected according to different system circumstances for optimizing the performance of DDLL.