线阵阵形畸变对目标方位估计性能影响及校正分析

Research on impact of shape distortion on the target azimuth estimation for soft linear array

在水声探测与定位方面,长线阵比舰载声呐有更好的性能,但其极易受到阵型畸变的干扰.通过理论分析、仿真研究以及实验数据处理等方法研究了阵形畸变对线阵到达角估计性能的影响,并提出了一种阵形校正方法.阵形畸变通过对波束成形运算中的导引矢量造成影响,使线阵测向性能劣化甚至失效.在常规线阵波束成形处理器以及自适应波束成形处理器的基础上,为了进行阵形畸变后数据的处理,首先给出一般的任意阵形波束成形算法,然后基于阵元位置误差对信号传输时延的改变,分析了阵形畸变对波束成形的导引矢量的影响.进一步给出了一种声学阵形标定方法,对阵形畸变做出估计并修正导引矢量.通过仿真分析以及实验数据处理可见:阵形畸变对常规波束成形以及自适应波束成形两种处理器均有影响,但比较而言,常规波束成形处理器对阵形畸变的鲁棒性更好一些;进行一定精度的阵形畸变修正后,两种处理器的到达角估计精度以及3分贝主瓣宽度均能得到明显改善.

Long linear array is more important than shipborne sonar in underwater target detecting and positioning, but it seems more sensitive to the shape distortion at the mean while.In this paper,the array shape distortion effect on soft linear array Direction of Arrival （DOA ）estimation performance was studied theoretically,then with simulation and field data process,an array calibration method was put forward.The steering vector of beamforming algorithm was changed when array shape was distorted,which will cause the degradation of line array direction per-formance,so far as to failure.Based on the conventional line array algorithm：Conventional BeamForming（CBF）and Adaptive BeamForming（ABF）,in the interest of process the data recorded from the distorted array,this paper first derived the general arbitrary array beamforming algorithm,and based on the impact analysis of array element position error act on the acoustical signal transmission delay,introduced how the beamforming steering vector was influenced by the array shape distortion.Next,an array shape calibration method based on acoustic signal was given, which correct the steering vector through estimating the array shape distortion.At last,the simulation and field data process proved the analysis,the performance of both CBF and ABF beamforming algorithm degradation which caused by the array shape distortion,in contrast,the CBF method was better,it has more robust than ABF method;The accuracy of DOA estimation output and the 3 dB width of main lobe have been significantly improved after ap-propriate array shape distortion adj ustment,for both CBF and ABF algorithm.The method mentioned here also useful to analyze the situation of three dimensional space.