低信噪比环境下的长码捕获新算法  

New acquisition scheme with high sensitivity for long code

作　　者：李文刚[1] 黄鑫磊[1] 刘龙伟[1] 

机构地区：[1]西安电子科技大学综合业务网理论及关键技术国家重点实验室,陕西西安710071

出　　处：《西安电子科技大学学报》2013年第4期29-36,共8页Journal of Xidian University

基　　金：111基地资助项目(B08038);西安电子科技大学基本科研业务费资助项目(K50510010027);国家青年自然科学基金资助项目(61201136);西电昆山研究院基金资助项目;东南大学移动通信国家重点实验室开放研究基金资助项目(2012D01)

摘　　要：针对微弱信号环境卫星导航定位系统信号捕获概率低的问题,提出多个码元累积提高信噪比的捕获算法.该算法以部分匹配滤波器结合快速傅里叶变换相干累积(Partial Matched Filtering based on Fast Fourier Transform,PMF-FFT)单元为基础,通过复用实现多码元相干累积和非相干累积,获得了更长的码相干时间和更大的非相干累积增益,提高了捕获灵敏度,缩短了捕获时间,提高了抗干扰能力.仿真结果表明,该算法能明显提高系统捕获性能,在相同信噪比条件下,较普通PMF-FFT算法在捕获概率上提高约4dB,可应用于我国北斗二代卫星导航系统.Focusing on the problem of low acquisition probability in the weak Satellite Navigation Position Systems signals environment, we propose an algorithm which can improve its acquisition signal-to-noise ratio （SNR） with multiple codes accumulation. The algorithm realizes codes coherent and incoherent accumulation by multiplexing the PMF-FFT（Partial Matched Filtering-Fast Fourier Transform）ceil, which can lead to a longer accumulation time and more coherent accumulation gain. Thus, it increases the capture sensitivity, shortens the capture time, and reduces the interference. Simulation shows that the algorithm in this paper can obviously improve the system＇s capture performance. It is better than the conventional PMF- FFT algorithm by close to 4 dB under the same SNR. The algorithm can be applied to the capture design in the second generation of COMPASS Navigation Satellite System.

关 键 词：捕获 高灵敏度 部分匹配滤波 高动态 全球定位系统 

分 类 号：TP927.21[自动化与计算机技术]