基于尺度变换的宽带线性调频信号时差/尺度差估计算法  

Scaling-based TDOA/SDOA estimation algorithm for wideband chirp signals

作　　者：郭付阳 张子敬[1] 杨林森[1] GUO Fuyang;ZHANG Zijing;YANG Linsen(National Lab of Radar Signal Processing, Xidian University, Xi＇ an Shaanxi 710071, China)

机构地区：[1]西安电子科技大学雷达信号处理国家重点实验室,西安710071

出　　处：《电波科学学报》2017年第4期441-448,共8页Chinese Journal of Radio Science

基　　金：国家自然科学基金(No.61571349)

摘　　要：提出了一种基于尺度变换的宽带线性调频信号时差和尺度差的快速算法.根据两路接收到的线性调频信号间调频率之比为尺度差的平方的特点,利用分数阶傅里叶变换分别估计出两路信号的调频率,即可获得尺度差的估计.将估计的尺度差对一路信号进行伸缩,并计算伸缩后信号与另一接收信号的时域相关,根据相关峰的位置估计出时差.相比于传统基于宽带互模糊函数的方法,该方法避免了二维搜索宽带互模糊函数的峰值,只需若干次快速傅里叶变换即可实现,能够显著降低运算量.仿真结果显示该方法在高信噪比下逐渐接近克拉美-罗下界.A method based on scaling is proposed to estimate the time difference of arrival （TDOA） and scale difference of arrival （SDOA） between two received wideband chirp signals. Using the relation that the square of SDOA equals to the ratio of chirp-rates of two received chirp signals, each chirp-rate of two chirp signals is first estimated using the fractional Fourier transform, and then the SDOA can be eval- uated. By scaling one received chirp signal with the estimated SDOA and evaluating the correlation of the scaled chirp signal and the other received chirp signal, the TDOA is finally estimated. Since the 2-D searching of the peak position of the wideband cross ambiguity function is avoided and it can be evaluated using only few fast Fourier transforms, the computational cost is significantly reduced. Simulation results show that the root mean square errors of the estimated TDOA and SDOA using proposed method closely meet to the Cramer-Rao lower bound under high signal-to-noise ratios.

关 键 词：分数阶傅里叶变换 宽带互模糊函数 时/尺度差估计 宽带线性调频信号 克拉美-罗下界 

分 类 号：TN911.7[电子电信—通信与信息系统]