水下多传感器阵列探测空中运动目标研究

This proposal addresses the problem of using an underwater acoustic multi-sensor array to detect a moving airborne target and estimate its trajectory parameters. To this end, the transmission law of the low-frequency sound wave propagating from the air into the water will be studied first. Then we will establish an improved acoustic field model based on the transmission matrix of the wavenumber integration. Furthermore, this model will be extended to the cases where the aero sound speed profile, the ocean waves, and the complex multi-layer structure of the ocean are taken into account. A fast method will be proposed to extract the Doppler shift features of the moving target radiating low frequency tones. We will also device a method for the near and the far target trajectory parameter estimation. This method is based on the least squares fitting of the predicted Doppler shift to the estimated micro-Doppler shift of the target noise measured under water. The large multi-sensor array can be divided into several sub-arrays, and the Doppler shifts associated with each sub-array and the time-delays between these sub-arrays are estimated. Combing the robust estimation of the incidence angle, the airborne target can be passively detected and the trajectory parameters can be estimated more accurately by fusing the Doppler shifts and the time delays of all the sub-arrays. Experiments on the lake and ocean will be carried out. A simulated source and a helicopter will be used to generate the noise as the targets. The influence of the wind and the sound speed profile in the air, the undulating surface of the water, and the underwater test environment will be analyzed, based on which we shall further improve the robustness of the method for both the near and the far target detections.

针对水下多传感器阵列探测空中运动目标并估计其运动参数的问题，研究低频空气声入水传播的声场规律，建立改进的基于传播矩阵的波数积分声场模型，并将其推广到考虑海面上空气声速剖面、海面波浪和海洋复杂多层结构的情况，提出计算运动目标低频线谱声源辐射声场多普勒频移特征的快速计算方法。建立基于水下接收信号微多普勒分析结果与模型预测声场多普勒频移最小二乘拟合的近程和远程目标参数估计的信息处理方法。将水下多传感器阵列划分多个子阵得到等效输出，分析各子阵输出的多普勒频移和时延并进行融合，结合稳健的入射角度估计，实现对空气声源被动探测和精确参数估计。开展湖上和海上实验研究，采用模拟声源和直升机作为辐射噪声源，分析空气中的风和声速剖面、水面的起伏、水下的测试环境等因素对空中目标运动参数估计的影响，完善近远程空中运动目标精确被动探测方法。

潜艇是处于全球领先地位的“隐形武器”之一，能对任何潜在敌对舰队造成沉重打击，是海军的主战装备。反潜机给潜艇构成了巨大威胁，在二者的对抗中处于绝对优势地位，可对潜艇发起搜索与有效攻击。因此，急需发展水下对空隐蔽探测技术，使潜艇舰载低频被动声呐具备对空预警能力，给潜艇争取宝贵的时间，规避求生或实施对空打击，改变潜艇“被动挨打”的局面。.本项目针对潜艇在水下隐蔽探测反潜机的难题，开展了空中运动声源辐射声波跨介质入水传播规律研究，突破了水下对空被动检测与高精度测向、测速等关键技术，解决了阵列声学孔径有限条件下低频弱目标远距离探测问题，并完成了海试实验验证，实现了水下对民用轻型直升机被动式声探测。主要研究结果如下：.1. 提出了传感器各向同性、相位与方向相关情况下的传感器位置、增益、相位联合校准方法等阵列现场校准方法，以及基于干扰加噪声协方差矩阵重构的自适应波束形成方法等稳健的自适应波束形成方法，实现了对阵列“大误差矫正、小误差容忍”，在阵列误差不确定、声学孔径有限条件下，提高了阵增益，改善了检测效果，经海试验证，实现了水下对民用小型直升机被动跨介质探测。.2. 提出了基于零陷矩阵滤波的稀疏谱估计方法、求根稀疏近似最小方差算法等高精度稀疏谱方位估计方法，实现了小快拍、低信干比条件下水下对直升机快速高精度测向。.3. 提出了多普勒调频小波快速变换测速方法，提高了水下对直升机被动测速精度。.4. 提出了基于分布式多簇系统加权MUSIC目标直接定位算法等数据弱相关条件下稳健的分布式目标定位方法，提高了海洋波导环境下阵列接收信号空间相关性衰减条件下分布式系统的目标分辨能力，降低了定位误差，为水下多平台分布式协作对空定位奠定了技术基础。.研究成果突破了水下对空隐蔽声探测关键技术，可解决潜艇远距离“听不到”反潜机的痛点问题，为装备研制奠定了技术基础，对维护国家主权与领土安全、保障我国深远海海洋权益具有重要的军事意义和社会效益。