基于Fr-AF与改进RIDT的QFM-PRBC伪码估计  

Estimation for PN code of reconnaissance signal combined with QFM- PRBC based on Fr-AF and modified RIDT

作　　者：张天骐[1] 廖畅[1] 叶飞[1] 欧旭东[1] 

机构地区：[1]重庆邮电大学信号与信息处理重庆市重点实验室,重庆400065

出　　处：《重庆邮电大学学报（自然科学版）》2016年第2期156-161,共6页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

基　　金：国家自然科学基金(61371164;61275099;61102031);信号与信息处理重庆市市级重点实验室建设项目(CSTC2009CA2003);重庆市杰出青年基金(CSTC2011jjj140002);重庆市自然科学基金(CSTC2012JJA40008);重庆市教育委员会科研项目(KJ120525;KJ130524);重庆市研究生科研创新项目(CYS14140)~~

摘　　要：针对二次调频-伪码调相(quadratic frequency modulated-pseudo random binary phase code,QFM-PRBC)复合信号伪码估计的难题,提出一种基于分数阶模糊函数(fractional ambiguity function,Fr-AF)和改进的三角窗抗干扰核函数(reduced interference distribution kernel based on the triangular window,RIDT)变换的伪码估计算法。应用平方法解决伪码与信息码相位突变问题,并用累加平均减小平方法带来的噪声影响,利用分数阶模糊函数估计平方累加后信号的最高项和次高项系数,重构信号对接收端信号降阶;采用奇异值分解(singular value decomposition,SVD)对基于三角窗减少干扰的核函数变换加以改进以提取降阶后信号的伪码序列。仿真实验表明了算法的有效性,当累加次数为20且信噪比在-4 d B以上时,伪码可以正确估计。To estimate the pseudo noise（ PN） code of reconnaissance signal combined by the quadratic frequency modulated（ QFM） and pseudo-random binary phase code（ PRBC）,the paper presents an algorithm based on the fractional ambiguity function and a modified time-frequency analysis method using a reduced interference distribution（ RID） kernel based on the triangular window. Firstly,the square method is computed to eliminate the phase mutation,and the accumulated method is used to reduce the bad effect of the square method. Secondly,fractional ambiguity is adopted to estimate second and third coefficients. Then the original signal is multiplied by the conjugated signal which is reconstructed by the estimated coefficients to get a new compound signal. Thirdly,the new compound signal consists of sine carrier and the PRBC signal,and the original PN code can be restored by the way of RIDT which is modified by the singular value decomposition（ SVD）. The simulation results show that the algorithm is feasible. The correct PN code is obtained when signal-to-noise ratio is more than or equal to- 4 d B,which shows good performance.

关 键 词：二次调频-伪码调相 分数阶模糊函数 改进的三角窗抗干扰核函数(RIDT) 伪码估计 

分 类 号：TN911.7[电子电信—通信与信息系统]