基于FFT-PMF的高效载波频偏捕获策略及性能研究  

Research on FFT-PMF Based Efficient Carrier Frequency Offset Acquisition

作　　者：胡涛[1] 张立新[1] 徐启炳[1] 

机构地区：[1]中国空间技术研究院西安分院,陕西西安710100

出　　处：《上海航天》2013年第5期34-38,共5页Aerospace Shanghai

摘　　要：为实现高动态和低信噪比环境中的信号捕获,提出了一种基于分段匹配滤波(FFT-PMF)结合非相干累加的方法进行伪码捕获,可将码相位-多普勒频率的二维搜索降为一维搜索,减少了捕获时间,并由非相干积分可以提高捕获余量。讨论了部分相关器长度和FFT点数对捕获性能的影响,推导出多普勒频移捕获范围和相关器长度的关系,提出了确定分段相关器长度的方法。仿真证明该法在伪码捕获的同时能高效准确地估计载波多普勒的频移,为分析捕获系统的捕获范围和选取相关器参数提供依据。To implement the signal acquisition in the large frequency offset and low signal-to-noise rate environment, a method of segment partial matched filtering （PMF-FFT） jointed non-coherent integration was put forward in this paper, which could reduce two dimensional search of code phase-Doppler frequency to one dimensional so the acquisition time was decreased and the acquisition margin could be improved by the non-coherent integration. The effects of the partial correlator＇s length and FFT points on the performance of PN code acquisition were discussed. The relationship between PMF size and Doppler frequency shift was derived, which provided theoretical basis for selecting partial correlators＇ length. The method for selecting segmental length of a correlator was presented. The simulation results showed that the method could estimate the Doppler frequency shift while acquiring the PN code, which could be the reference of the analysis of acquisition range and the parameter selecting of the correlator.

关 键 词：信号捕获 快速傅里叶变换 分段匹配滤波 非相干累加 

分 类 号：TN91[电子电信—通信与信息系统]