一种适用于大测绘带合成孔径声呐的运动补偿方法

当合成孔径声呐测绘带较大时,运动误差的空变效应严重,经典的相位中心重叠算法难以适用。为此,提出了一种适用于大测绘带合成孔径声呐的运动补偿方法。首先使用混合调制的拉格朗日时延估计算法对前后两帧回波的时延进行估计,之后使用线性回归方法拟合出运动误差,最后利用运动误差的估计值对回波进行逐点精确补偿。仿真数据的结果表明,该算法能够获得比相位中心重叠算法更好的运动估计结果,运动补偿后成像分辨率接近理论分辨率。使用该算法分别对高、低频合成孔径声呐的湖试数据进行了处理,水下地貌和小目标的成像质量均有明显提高。 

A motion compensation method for wide-swath synthetic aperture sonar

Motion compensation technique is crucially important to image reconstruction of synthetic aperture sonar (SAS).However,phase error caused by motion error varies in the wide slant range,especially for wide-swath synthetic aperture sonar,which makes displace phase center (DPC) algorithm invalid.A motion compensation method based on adaptive time delay estimation is presented.This method utilizes mixed modulated Lagrange explicit time delay estimation (MMLETDE) algorithm to obtain estimation of time delay,then a linear regression model is used to fit motion error.Lastly,raw data can be compensated point by point with the estimated sway and heave.Simulation results show that this method can get better motion error estimation,and actual resolution of images approximates ideal resolution.The method is applied to high frequency and low frequency SAS lake-trial dataset,which shows image qualities of terrain and small targets are both improved evidently.