一种基于频差补偿的相位谱时延估计方法

摘要

针对影响射频窄带信号时延估计精度的3个主要因素：中频偏差、信号带宽及信噪比,提出了一种基于频差补偿的相位谱时延估计方法.其采用平方倍频法分别估计两路信号的中频,通过频差补偿消除中频偏差对时延估计精度的影响;利用线性调频Z变换（CZT）在有限带宽内增加时延估计的有效点数;并针对相位法自身的特点利用Kalman滤波器优秀的抗噪声特性提高时延估计的精度.理论分析和实验仿真均验证了该方法的有效性.%Three main factors which affect the accuracy of time delay estimation（TDE） for narrowband radio frequency（RF） signals are mentioned： intermediate frequency difference,signal bandwidth and SNR.A phase spectrum TDE method based on frequency difference compensation（FDC） is proposed.The intermediate frequencies（IF） of both received signals are estimated respectively using frequency doubling method,and FDC method is used to eliminate the side effect of IF difference to TDE result.Then,chirp Z transform（CZT） is applied to increasing the available frequency bins within a limited bandwidth.Meanwhile,Kalman filter is also adopted because of its excellent anti-noise characteristics to improve precision of TDE.Both theoretical analyses and computer simulation results show the effectiveness and advantage of the proposed method.