二次雷达混扰信号的迭代投影分选算法

摘要

针对二次雷达应答信号混扰导致解码错误的问题,提出一种迭代投影分选算法.综合考虑天线结构、残留载频等因素建立阵列信号混扰模型,通过对模型中待求变量的最大似然估计分析,给出双矩阵变量优化模型,以非圆复信号快速独立成分分析(Noncircular complex fast independent component analysis,nc-FastICA)算法得到应答信号初始值,进而根据二次雷达应答信号零/恒模(Zero/constant modulus,ZCM)特性提出迭代投影分选算法,最终完成对混扰信号的分选.仿真结果表明,在应答机之间相距较近、天线非精确调整等复杂环境下,本算法可从混扰应答信号中有效地分选出各应答信号,且分选性能明显优于快速独立成分分析算法.%To overcome the problem of decoding errors of secondary surveillance radar (SSR) due to the phenomenon of garble,an iterative projection algorithm for separating the garbled replies is proposed.Firstly,a signal model for the garbled replies is established in which the influence factors such as antenna structure,residual carrier frequency and so on are taken a full consideration,and an optimization model with double matrix variables is proposed based on the maximum likelihood estimation of the unknown variable in the model.Then,the initial value of replies is estimated by the algorithm of noncircular complex fast independent component analysis (nc-FastICA).And then,the iterative projection algorithm based on the zero/constant modulus (ZCM) property of SSR replies is proposed to separate garbled SSR replies.Numerical simulations show that the proposed method can separate multiple replies accurately in the complex environment such as shorter distance of the transponders and inaccuracy in the antenna and so on,and it outperforms the algorithm of nc-FastICA obviously in the separation performance.