浅海负跃层条件下的双基地有源探测实验及定位声速修正
Experimental verification of bistatic active detection and propagation speed correction in shallow water with negative thermocline
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摘要: 为了研究浅海条件下海底固定水平阵和机动声源的双基地有源探测性能,建立了浅海双基地有源探测仿真模型,分析了实验海区负跃层条件下的传播损失和多途能量扩展损失,实现了双基地有源探测的性能预估。以模型仿真为基础,在南海北部海域开展了一次浅海双基地有源探测实验.针对定位中的声速与实验中目标回波的脉冲传播速度的偏差导致定位精度下降的问题,提出了一种目标回波脉冲传播速度近似估计方法。实验结果表明,双基地有源探测可在浅海负跃层条件下实现对水中目标的有效探测,多个实验站位的回波信噪比实测值与仿真预测值符合较好,定位声速近似估计方法可进一步提高定位精度。Abstract: In order to estimate the capability of bistatic active detection based on a stationary horizontal array and flexible source in shallow water environment,a bistatic active signal simulator is developed.Further,the transmission losses and energy spreading losses are analyzed and the capability of bistatic active detection in shallow water environment is estimated.An experiment was conducted in the South China Sea according to the predicted detection range.The bias between the selected reference sound velocity and the pulse propagation velocity of the target echo degrades the positioning accuracy.An approximate method for the pulse velocity estimation is proposed to reduce the positioning error caused by the bias.Experimental results show that bistatic active detection can effectively detect target in negative thermocline environment,the estimated SNR(Signal-to-Noise Ratio) with the simulator are reliable,and the positioning accuracy can be improved by using estimated pulse velocity.
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