基于时延优化的三维成像声呐视野展宽方法研究

针对平面阵,研究并探讨了一种近场聚焦波束形成中时延参数的优化方法,以扩大三维成像声呐的有效视野范围。该方法是在方位角和俯仰角重新定义时,将精确的近场时延表达式按泰勒公式展开,取前三项,并对每一项进行加权。然后,通过求三个加权系数的偏导,再令其等于0,得出最优加权系数,此时优化的时延表达式与精确的近场时延表达式的误差最小,即优化的时延表达式更接近于精确的时延表达式,能够有效地用于扩大成像声呐的有效视野。最后,通过计算机仿真验证了该方法的有效性。

Delay optimization based visual field broadening method for 3D imaging sonar

A delay optimization design method for near-field focused beamforming is studied to broaden the visual field of the three dimensional imaging sonar with a planar array. In this method, the first three terms in the Taylor series of the exact near-field delay expression are selected and weighted under the new definitions of the azimuth and pitching angles. By setting the partial derivatives of the three weighting coefficients equal to zero, the optimum weighting coefficients can be obtained. Therefore, the difference between the delay expression of the three weighted terms with optimum weighting coefficients and the exact near-field delay expression is minimal. In other words, the delay expressed by the three weighted terms with optimum weighting coefficients is very close to the exact near-field delay, which can be used effectively to broaden the visual field of imaging sonar. Finally, simulation for a planar array is conducted to verify the effectiveness of the proposed method in this paper.