多载波基带信号相参时差估计算法与分析

Coherent Integration TDOA Estimation Algorithm and Analysis of Multi-Carrier Baseband Signals

时差估计精度与信号在频域上的分布情况以及信号能量和噪声有关。多载波信号的频率信息和能量在频域上分布区间大,通过多载波信号的相参积累,可以有效利用信号在整个区间内的频域信息和能量来提高时差参数的估计精度,克服单载波信号带宽窄能量低导致的时差估计精度不高的问题。本文针对多载波基带信号的时差估计问题,在单载波基带信号互相关函数分析的基础上,推导了多载波基带信号互相关函数,并分析了其相位关系,通过相位补偿实现了多载波基带信号互相关函数的相参积累,并理论分析了多载波信号时差参数估计性能与信号各参数的关系。蒙特卡洛仿真表明,提出的多载波基带信号相参时差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。

The estimation accuracy of time difference of arrival(TDOA)is determined by the frequency distribution and energy of signal and noise.Multi-carrier signals have broad distribution in frequency domain,the problem of low estimation accuracy for TDOA of single carrier signal can be overcome through coherent integration to improve the use of efficient bandwidth and energy.Focus on the TDOA estimation problem of multi-carrier baseband signals,this paper first analyzed the cross correlation function(CCF)of single carrier signal,and the phase relation of baseband signal between carrier frequency and TDOA is investigated.Then the CCF of each multi-carrier signal is deduced,and the phase relation of each CCF is analyzed.Coherent integration is realized by phase compensation.The theory performance of TDOA estimation for multi-carrier signals are analyzed,and the influence of the signal parameters on TDOA estimate accuracy is derived.Monte Carlo simulations validate that the accuracy of proposed coherent integration TDOA estimation algorithm for multi-carrier signals exceed that of single carrier signal obviously,and the performance improvements accord with the theory analysis well.