基于模糊统计理论的浅海混响抑制与低速目标检测技术研究

Reverberation is one of the prime reasons which influence the detection performance of the shallow water active sonar. The Doppler frequency shift of the low speed targets is small. And it is difficult to separate the reverberation and the low speed target echoes based on the frequency domain processing. How to detect the low speed targets in shallow water is one of the most difficult problems for the sonar researchers. The shallow water reverberation contains reverberation edges, multi targets influences and powerful shadows, and it is also stochastic and fuzzy. In the light of the characteristics of the shallow water reverberation, the techniques of the modeling of fuzzy statistical model and fuzzy processing are studied firstly. And these techniques are used to detect and suppress the non-homogeneities. To improve the detection performance in shallow water, the fuzzy perception methods and the knowledge-based fuzzy soft decision are then researched. Finally, the two-dimension statistical properties of the detected target member degree values are studied and this is used to discriminate the low speed target echo and the shallow water reverberation. In this project, the techniques of the non-homogeneity detection and suppression, the knowledge-based fuzzy soft decision, and the discrimination of the two-dimension statistical properties of the target member degree values are researched. The research achievements may largely improve the detection performance of the low speed targets in shallow water, and make a contribution to the anti-submarine and combat capability of our country in shallow water.

混响是影响浅海主动声呐检测性能的主要因素之一。低速目标回波多普勒频移小，传统频域处理很难有效分离混响和低速目标。如何对浅海低速目标进行检测是水声领域亟待解决的难题之一。浅海混响非常复杂，存在混响边缘、多目标干扰、强遮挡等非均匀性，也具有随机性、模糊性等强不确定性。针对浅海混响特点，本课题拟基于模糊统计理论，首先研究浅海声呐数据的模糊统计模型和模糊处理方法，以检测、抑制浅海混响的非均匀性；然后研究模糊感知方法和知识基软判决检测器，以提高浅海目标的检测性能；最后统计分析检测输出的目标隶属度值及其二维统计特性，根据统计特征，判别低速（包括静止）目标与浅海混响。本项目对浅海混响非均匀性检测与抑制技术、基于环境感知的知识基软判决检测技术和目标隶属度二维统计特征分析与判别技术进行了研究，研究成果有望大幅提高浅海低速目标的检测性能，为我国浅海反潜能力与浅海作战能力的提高做出贡献。

本项目主要对浅海非均匀背景混响建模及抑制技术和浅海非均匀混响中的低速目标检测技术进行了研究。基于模糊统计理论，完成了混响背景及声呐目标隶属度函数建模和模糊统计归一化处理混响抑制技术，并基于模糊统计归一化处理混响抑制技术完成了知识基混响抑制及目标检测方法和非均匀、非瑞利混响背景下的背景数据参数自适应估计方法。仿真和试验数据验证表明，所提方法能够提升复杂浅海非均匀背景中的背景功率估计精度和低速目标检测性能，对于复杂浅海环境中的低速目标探测性能提升具有重要意义。