水下目标二维散射特性测量方法

A method of measuring the 2-D scattering characteristics of underwater targets

基于合成孔径原理,提出一种水下目标二维散射特性测量方法,该方法采用声呐基阵静止而目标作合作匀速直线运动的模式.推导了前述模式下的目标回波信号模型.对回波信号进行二维成像处理,利用反投逐点算法进行方位向的聚焦处理,进而得到目标在距离和方位维的二维散射特性.给出计算机仿真和水池试验的回波数据处理结果,得到水下目标散射特性的二维空间分布,方位向理论分辨率达到0.04 m,且分辨率与距离和频率无关.该方法可用于目标特征缩减和目标识别.

A new method was developed for measuring the 2-D scattering characteristics of underwater targets based on the synthetic aperture principle. This method is different from existing synthetic aperture sonar and inverse synthetic aperture sonar. Synthetic aperture sonar demands that the target is stationary and the sonar array moves at a constant velocity along a straight line. Inverse aperture sonar requires that the sonar array is stationary and that the target moves non-cooperatively. However, the new method lets the sonar array be stationary and the target move cooperatively at a constant velocity along a straight line. The target＇s signal echo model was deduced first. Then the signal echo was processed using a pixel by pixel algorithm named back-projection to get the 2-D scattering characterization of targets in both range and azimuth. Finally the results of the computer simulation and tank trials were compared. The results clearly show the 2-D spatial distribution of scattering by underwater targets, and azimuth resolution reached 0.04m independent of range and frequency. The method can be used for reduction of target characteristics and target identification.