基于严格解析谱的多子阵合成孔径声纳距离多普勒成像算法

Exact Analytical Two-Dimensional Spectrum Based Range Doppler Algorithm for Multiple Receiver Synthetic Aperture Sonar

借鉴顺轨双基地合成孔径雷达中双根号形式的斜距变化历程处理方法,推导了多子阵合成孔径声纳(SAS)准解析二维谱;求解准解析二维谱中唯一的未知量——半双基角(HQBA),解其一元四次方程得到不同等效基线长度下的HQBA解析表达式;将HQBA表达式代入准解析二维频谱,获得了严格的解析多子阵SAS二维谱,以解决多子阵SAS精确二维谱的推导问题;在此基础上,提出了一种适用于多子阵SAS的距离多普勒成像算法,以解决传统偏置相位中心近似方法存在的近距点散焦问题,并通过仿真实验和湖试数据成像结果验证了所提出算法的有效性.

The slant range history of multiple-receiver synthetic aperture sonar（SAS）is a typical doublesquare-root（DSR）term,which makes it difficult to directly obtain an analytical two-dimensional（2-D）spectrum using the principle of stationary phase.In order to solve this problem,aquasi-analytical 2-D spectrum except for the unknown half quasi-bistatic angle（HQBA）was derived based on the method used in the tandem bistatic synthetic aperture radar.By solving the fourth-order equation with respect to the HQBA,some expressions of the HQBA in different equivalent baselines were obtained.After substituting the derived HQBA into the quasi-analytical 2-D spectrum,an exact analytical 2-D spectrum was obtained and the DSR term was solved successfully.Based on the derived 2-D spectrum,an extended range Doppler algorithm was proposed for the imaging of multiple-receiver SAS and the solving of the defocusing problem of closer range point target.The results of simulation and experiment have verified the effectiveness of the derivation and the proposed algorithm.