一种二级分段PMF-FFT卫星信号捕获算法  

A two-stage segmented PMF-FFT satellite signal acquisition algorithm

作　　者：黄海生 张弛 李鑫 丁福恒 HUANG Haisheng;ZHANG Chi;LI Xin;DING Fuheng(School of Electronic Engineering,Xi’an University of Posts and Telecommunications,Xi’an 710121,China;Unicom(Shaanxi)Industrial Internet Co.,Ltd.,Xi’an 710086,China)

机构地区：[1]西安邮电大学电子工程学院,陕西西安710121 [2]联通(陕西)产业互联网有限公司,陕西西安710086

出　　处：《西安邮电大学学报》2024年第1期32-40,共9页Journal of Xi’an University of Posts and Telecommunications

基　　金：陕西省重点研发计划项目(2022GY-011)。

摘　　要：针对在小点数快速傅里叶变换(Fast Fourier Transform,FFT)中,经典分段匹配滤波(Partial Matched Filtering,PMF)与FFT相结合的PMF-FFT卫星信号捕获算法存在增益损失,导致捕获灵敏度低、频率覆盖范围小和搜索速度慢的问题,提出了一种改进的二级分段PMF-FFT卫星信号捕获算法。截取部分FFT频率分量,缩短算法有效频率覆盖范围,以改善分段求和带来的包络增益衰减;采用在FFT频率分量中间位置追加搜索的方法,以改善FFT带来的扇贝损失;使用从粗略搜索到高精度搜索的策略,以减少搜索次数,提高搜索速度。仿真结果表明,相比经典PMF-FFT算法,在FFT点数不大于64点的情况下,改进算法能有效提高搜索增益和搜索速度,在8点FFT、125 Hz频率精度条件下,平均增益提升了22.19%,搜索次数减少了7.69%。In the case of fast Fourier transform(FFT)with a small number of points,the traditional partial matched filtering(PMF)combined with FFT satellite signal acquisition algorithm,PMF-FFT,has significant gain loss leading to low capture sensitivity and small frequency coverage range that results in slow search speed.An improved two-stage segmented PMF-FFT satellite signal acquisition algorithm is proposed to solve this problem.By truncating some FFT frequency components and shortening the effective frequency coverage range of the algorithm,the envelope gain attenuation caused by the segment summation is improved;by appending searches at the middle position of the FFT frequency components,the scallop loss caused by the FFT is improved;by adopting a strategy from rough search to high-precision search,the number of searches is reduced and the search speed is increased.Simulation results show that compared with the traditional PMF-FFT algorithm,the improved algorithm can effectively improve the search gain and search speed when the number of FFT points is not more than 64.Under the condition of 8-point FFT and 125 Hz frequency accuracy,the average gain is increased by 22.19%,and the number of searches is reduced by 7.69%.

关 键 词：全球导航卫星系统 捕获算法 分段匹配滤波 快速傅里叶变换 包络衰减 扇贝损失 

分 类 号：TP301.6[自动化与计算机技术—计算机系统结构]