为使相控阵三维摄像声纳系统中的稀疏阵列在整个探测范围内都具有稳定的波束图性能,文中提出了一种兼顾远场与近场的稀疏阵列优化方法. 首先通过对近场波束图的分析,构建了一种适合实际工程应用的近场稀疏阵列优化的能量函数,并对该能量函数加以简化,以减少优化过程的计算量,然后利用寻优算法对简化后的能量函数进行最小化寻优运算,从而得到满足近场需要的稀疏布阵结果. 为进一步获得适用于远场的稀疏率更高的阵列,对近场稀疏阵列设计的结果进行了二次优化. 利用该稀疏优化方法对一个100×100 的二维矩形换能器阵列进行优化,并与现有文献方法进行了对比,结果表明文中方法获得的稀疏阵列在远场和近场条件下的各个探测距离都能提供期望的波束图性能,同时保持了与其他方法相近的稀疏率.

In order to attain stable and global beam-pattern characteristics of sparse arrays in phased-array 3D ima-ging sonar systems, an optimization method to design sparse arrays in both the far-field and the near-field conditionsis proposed. In this method, first, based on the analyses of the near-field beam pattern, a new energy function isbrought forward for the near-field sparse array optimization in practical engineering applications. Next, the functionis simplified to reduce the computation load. Then, an appropriate near-field sparse array is obtained by minimizingthe simplified energy function via an optimization process. Finally, a second-step optimization of the near-fieldsparse array is carried out to obtain an array with higher sparse ratio for far-field design. The proposed method isemployed to optimize a 100×100 rectangular planar transducer array, and the results are compared with thoseobtained by the existing methods. It is indicated that the proposed method helps to obtain sparse arrays possessingdesired beam-pattern characteristics for both the far-field and the near-field design in random working ranges, withthe sparse ratio being close to those of the existing methods.