圆合成孔径声呐多点定位运动补偿

圆合成孔径声呐(CSAS)的成像性能受平台运动误差影响而下降,利用单侧回波可估计CSAS基阵的斜距误差,但单侧回波在小测绘带时无法估计升沉误差,针对此问题,提出了一种利用单侧回波信号的声呐平台三维运动估计和补偿方法。首先,对CSAS在不同观测角度的目标回波取极大值获得目标回波的到达时间;其次,基于多个点目标的到达时间建立CSAS三维定位模型;然后利用列文伯格-马夸尔特方法对声呐三维坐标进行估计;最后将位置估计结果与时域反投影成像方法结合实现对目标的成像.仿真结果表明:该方法能精确估计声呐平台运动误差,其空间坐标的估计误差小于仿真信号波长的1/8,从而精确补偿了CSAS在不同空间采样点上的阵元回波时间差,显著提高了目标成像质量。湖上试验结果表明,该算法能够实现对CSAS的运动误差补偿。仿真和试验结果均验证了方法的可行性和有效性。 

Multilateration motion compensation for circular synthetic aperture sonar imaging

The platform motion error reduces the imaging performance of Circular Synthetic Aperture Sonar(CSAS).The slant-range error of CSAS can be estimated by the single-side echo,but the heave cannot be estimated by single-side echo in narrow-swath.Aiming at this problem,we propose a method of platform 3D-motion estimation and compensation based on echo signal.Firstly,it obtains the arrival time of CSAS by taking maximum values of CSAS target echoes from different observation angles.Secondly,the CSAS 3D positioning model is established based on the arrival time of multipoint targets.Then the three-dimensional coordinates of the sonar are estimated by using the Levenberg-Marquardt method.Finally,the position estimation results are combined with the time-domain back-projection imaging method to realize the imaging of the target.Simulation results show that the proposed method can accurately estimate the motion error of the sonar platform,and the estimation error of the spatial coordinates is less than 1/8 of the simulated signal wavelength,thus accurately compensating the echo time difference of CSAS array elements at different spatial sampling points,and significantly improving the imaging quality of the target.The experimental results show that the algorithm can compensate the motion of the circular synthetic aperture sonar without relying on the sensor data.Simulation and experimental results show the feasibility and effectiveness of the proposed method.