GPS接收信号中线性扫频干扰的抑制  

LFM interference mitigation in GPS received signal

作　　者：周柱[1] 卢树军[1] 张尔扬[1] 李耀明[2] 

机构地区：[1]国防科技大学电子科学与工程学院,湖南长沙410073 [2]空军装备研究院通信所,北京100085

出　　处：《国防科技大学学报》2013年第1期70-76,共7页Journal of National University of Defense Technology

基　　金：国家部委资助项目(9140C0202011003)

摘　　要：研究了阵列接收的GPS接收信号中线性扫频(LFM)干扰的抑制问题。LFM信号瞬时频率的估计是抑制干扰的关键,而要准确估计信号瞬时频率,必须抑制接收信号时频分布中交叉项干扰。本文对接收信号矢量进行白化,得到信号矢量白化后的空时频分布(STFD)矩阵。文中推出一个与传统方法获得的判决变量不同的判决变量,用该判决变量可以更加清晰地选出LFM信号在时频分布中的自项。根据时频脊点的分布估计LFM信号频率参数以及信号瞬时频率,之后即可根据瞬时频率构建陷波器滤除干扰。仿真表明该方法能够将受交叉项严重干扰的接收信号时频分布映射为清晰的接收信号自项的时频分布,在数据快拍数满足一定要求时可以很好地抑制掉LFM干扰。Linear Frequency Modulation （LFM） interference mitigation in received GPS signal by antenna array was studied. The pivotal problem of LFM interference suppression is the instantaneous frequency estimation, With this conception, the cross-term in the time-frequency distribution must be suppressed. Thus the received signal vector was whitened and the Spatial-Time-Frequency Distribution （STFD） matrix was formed by utilizing the whitened signal vector. A decision variable which is different from traditional one was deduced. By using the decision variable, the auto-term in the time-frequency distribution of the LFM signal can be selected clearly. Based on the time-frequency distribution of the auto-terms, the parameters and the instantaneous frequency of the LFM signals can be estimated. According to the instantaneous frequency, corresponding notch filters can be formed, which can mitigate the interferences. Through simulation, it can be viewed that the time-frequency distribution of the received signal which is interfered seriously by the cross-term can be mapped into a clear time-frequency distribution of auto-terms of the signal. Under the condition that the number of snap is enough, the LFM interferences can be suppressed clearly.

关 键 词：LFM信号 空时频分布矩阵 白化矩阵 判决变量 陷波器 

分 类 号：TN911.72[电子电信—通信与信息系统]