双基地声呐接收站散射波低截获技术

双基地声呐的接收站因散射主动信号存在暴露的风险,对此提出了基于发射声屏蔽的双基地声呐低截获技术。发射站采用垂直发射阵,利用屏蔽权对原始信号进行预处理,获得的低截获信号在接收站处被自动抵消,从而降低接收站散射信号的能量。仿真结果表明,发射声屏蔽技术能有效增加接收站散射信号到达目标处的能量衰减,而对到达接收站处的待测目标散射信号则无较大影响。该方法突破了以往低截获技术只是改变信号能量时频域分布的局限(在信号处理层面),利用多途结构真实降低了被截获信号能量(在物理层面),并适用于多种信号形式。

Low probability interception of scattered wave from the receiving station of bistaitc soanr

To avoid the risk that the receiving station may be exposed due to scattering the active signal, the bistatic low probability of interception (LPI) technique based on acoustic shielding technique is proposed. Utilizing the acoustic multi-path feature of the direct signal, the original signals are pre-processed by acoustic shielding at the transmitting station to get the LPI transmitting signals of bistatic sonar. Simulation results show that:compared with original signal, when transmitting the LPI signal, the interception signal received by the target attenuates significantly; the middle part of the interception signal attenuates more than the both sides of the interception signal do in time domain; however, the target scattering signal received by the receiving station essentially unchanged. The proposed LPI technique enhances the anti-intercept ability of the scattering signal from the receiving station and reduces the quality factor of the target without affecting that of the receiving station. And, the proposed LPI technique helps the receiving station to maintain stealth and improves the underwater-acoustical countermeasure ability of the bistatic sonar. The traditional LPI waveform designs only change the signal power distribution along the time-frequency axis and the chaos characteristic to increase the complexity of detecting signal. The proposed method really reduces the energy of the interception signal. The proposed method can apply to all kinds of broadband signal and provides a new idea for LPI sonar.