【摘要】 针对接收信号存在大频偏的高动态直扩接收机伪码捕获时间长的问题,分析了高动态环境下匹配滤波检测器相关长度与相关后输出信噪比的关系,比较了相关后的几种检测算法的性能,分析了FFT校频技术的性能.在此基础上提出一种在高动态环境下的码捕获新方法,该方法采用分段匹配滤波相关、最大选择检测算法和二次内插的FFT校频技术.根据新方法设计了捕获电路模块.Matlab系统仿真结果表明,新的捕获方法可以容忍校正更大的频率动态范围,在较低信噪比下快速完成码捕获功能.更多还原

【Abstract】 Presents a new code acquisition method to solve the problem of long code-acquisition time in high dynamic DSSS receivers having large frequency offset. The study analyses first the relationship between the length of the matched filter and SNR after correlation. It then compares the performance in different detection algorithms, and analyses the performance of FFT frequency correction technology. The method presented adopts segmented matched filter detector, maximum-selection detection algorithm and FFT frequency correction with quadratic interpolation. A new code acquisition circuit module is designed. The result of Matlab simulation shows that the new acquisition method can tolerate larger frequency dynamic range and can rapidly finish code acquisition under lower SNR.更多还原