基于CAF相参积累的多载波信号时频差估计算法

TDOA/FDOA estimation algorithm of multi-carrier signals based on CAF coherent integration

多载波信号具有丰富的频域信息,相参积累能够拓宽信号的有效带宽,克服单载波信号带宽窄导致时差(time difference of arrival,TDOA)、频差(frequency difference of arrival,FDOA)参数估计精度不高的问题。以多载波信号的检测定位为背景,研究了基于多个载波信号互模糊函数(cross ambiguity function,CAF)相参积累的TDOA/FDOA参数估计算法,为多载波信号的无源定位提供高精度的定位参数估计方法。基于接收信号模型,推导了多载波信号的互模糊函数,从TDOA/FDOA两个维度分析了不同载波信号CAF的相位关系,通过相位补偿实现了多载波信号CAF的相参积累,并从理论上分析了TDOA/FDOA参数估计的性能改善情况。蒙特卡罗仿真表明,提出的多载波信号相参积累TDOA/FDOA估计算法性能明显优于单载波信号的估计性能,性能改善情况与理论分析一致。

Multi-carrier signals have broad distribution in frequency domain,so the problem of low estimation accuracy for time difference of arrival(TDOA)and frequency difference of arrival(FDOA)of single carrier signal can be overcome through coherent integration to improve the efficient bandwidth.Focusing on the problem of multi-carrier signals detection and localization,the TDOA/FDOA estimation algorithm based on multi-carrier signals cross ambiguity function(CAF)coherent integration is researched,and a high accuracy location parameters estimation method for multi-carrier signals passive location is provided.Based on the received signal model,the CAF of each multi-carrier signal is deduced,and the phase relationship of each CAF is analyzed through TDOA and FDOA dimensions.Coherent integration is realized by phase compensation and the performance improvements of TDOA/FDOA estimation are analyzed in theory.Monte Carlo simulations validate that the accuracy of the proposed TDOA/FDOA estimation algorithm based on multi-carrier signals coherent integration exceeds that of the single carrier signal obviously,and the performance improvements are the same as the theory analysis.