基线附近区域为双基地声呐的探测盲区,当目标位于基线区域时,目标回波与强直达波干扰同时同向到达,基于空域滤波等的传统直达波抑制方法失效。为实现双基地声呐对盲区内目标的探测,提出了一种适用于多发射阵元系统的发射声屏蔽技术。发射声屏蔽技术利用目标回波与直达波相异的多途信道结构特性,自动屏蔽在接收站位置处的直达波而不影响目标回波,且不需接收站进行任何后续处理。在已知回波信道信息时,发射声屏蔽技术可进一步实现对回波信号的聚焦,提高信干比。仿真结果表明,在不同信道条件下发射声屏蔽均能有效抑制直达波干扰。利用发射声屏蔽技术,双基地声呐能够实现对基线区内目标的检测。The area near the baseline is a dead zone for bistatic sonar.The echo and the strong direct wave will arrive in the same place simultaneously when the target is in the baseline area and the direct wave suppression method based on a spatial filter will fail.To detect targets in the dead zone,a transmission shielding method for a multi-element transmit system is proposed.The transmission shielding automatically suppresses the direct wave at the receiving station utilizing structural differences in multiple channels between the echo and the direct wave.The transmission shielding further focuses on the echo,so as to improve the Signal-Noise Ratio,using known echo channel information.The simulation results show the transmission shielding method can suppress direct wave interference for different multipath channels.Bistatic sonar can detect targets in the baseline area utilizing the transmission shielding method.国家自然科学基金资助项目(51179034); 海洋工程国家重点实验室(上海交通大学)资助项目(1211
