多基地空时码探测信号设计及时反相关检测技术

为实现浅海复杂环境下的多基地声纳多源目标回波分辨,本文设计了一种适用于多入多出垂直阵信道环境下的空时码探测信号,并针对倾斜垂直阵的多途子信道差异问题,提出了信号的时反相关检测技术.空时码探测信号采用伪随机信号调制,具有良好的正交性,能在抗子信道严重衰落的同时,分辨多源目标回波.垂直阵受水流冲击,呈倾斜状态时,其多途子信道不一致性会导致各子信道传递信号无法在接收端聚焦,使阵列增益受损,同时导致时延测量能力下降和信号判决错误率上升,为此本文设计了信道训练信号用以估计多途子信道环境,通过虚拟时间反转镜获得子信道不一致条件下的最佳匹配检测信号,实现对接收信号的时反相关检测.仿真结果表明,本文所设计的探测信号和检测方法,能够克服复杂的信道条件和多途子信道不一致性引起的检测问题,满足多基地声纳探测需求,实现多源目标回波分辨.

Design of multistatic sonar space-time code detection signal and time reversal copy-correlation detection technology

A space-time code (STC) detection signal is designed for multistatic sonar to distinguish the multiple access echoes in the shallow water, and a time reversal (TR) copy-correlation detection method is presented for solving the problem of multi-path sub-channel differences when the vertical array is oblique. STC detection signal has a good orthogonality through modulating with pseudo-random signals, can distinguish multiple access target echoes while combating with sub-channel attenuation. The vertical array affected by current is oblique, its multi-path sub-channel differences causing signals from different sub-channels can not focus on the receiving end, so the array gain decreases. Meanwhile, it causes resolution to decline and the error rate of signal judgment to rise. Channel training signal is designed to estimate the sub-channel multipath environment, and the best matched detection signal for sub-channel differences is got through virtual time reversal mirror (VTRM) with the estimated channels and the received signal being detected by TR copy-correlation. Simulation results of tristatic sonar (two transmitters and one receiver) show that the SPC detection signal and TR copy-correlation can meet the requirements of multistatic sonar detection and distinguish the multiple access echoes in low SIR and complex channel environment. The best matched detection signal is got through VTRM (virtual time reversal mirror) with the estimated channels, and the received signal is detected by TR copy-correlation. Simulation results of tristatic sonar (two transmitters and one receiver) show that the STC detection signal and TR copy-correlation can meet the requirements of multistatic sonar detection and distinguish the multiple access echoes in low SIR environment.
Keywords： STC detection signal TR copy-correlation detection multi-path sub-channel differences distinguishing the multiple access echoes