认知天波超视距雷达低可探测目标检测方法研究

The low observable target detection and ionosphere analysis techniques have become the research hotspot of Skywave Over-The-Horizon Radar(SWOTHR). Ionosphere contamination and small, slow target detection in complex electromagnetic environments are bottleneck of improving SWOTHR's target detection performance.This problem is needed to be further studied.As a new type of radar concept, cognitive radar can improve the system adaptability, is the important direction of the development of radar technology. This project focuses our attention on the new generation of the Cognitive Skywave Over-The-Horizon Radar (CSWOTHR), based on the environmental perception and with the skywave radar active adaptation ability as core, carries out the research in view of the small, slow low detectable targets detection with the joint adaptive processing method of transmiting and receiving.The mechanism of system actively adapting themselves to the external environments based on the system architecture design is analysed. Through analyzing the key problems such as the ionospheric channel contamination and the clutter environments cognition, transmitting signal waveform design and optimization, the joint adaptive processing methods of transmiting and receiving,the low observable target detection based on knowledge aid and the online estimation is implemented to relax the bottleneck problem that the performace of SWOTHR is conditioned by the external environments.The Expected research results will improve performance of SWOTHR to detect low observable targets, expanding the function of executing multiple tasks , broaden the developing cognitive radar theory, and thus has important theory value and broad application prospects.

低可探测目标检测与电离层分析技术已成为新一代天波超视距雷达的研究热点，电离层污染与复杂电磁环境下小、慢目标探测严重限制了天波雷达目标检测性能的提升，有待深入研究。认知雷达作为一种新型雷达概念，可全面提升雷达系统能力，是雷达技术发展的重要方向。本项目以新一代认知天波超视距雷达为研究对象，以环境感知为基础，以雷达系统主动适应外部环境的非平稳变化能力为核心，研究小、慢低可探测目标检测的收发联合自适应处理方法。通过架构设计，分析系统主动适应外部环境的机制；通过研究电离层信道污染与杂波环境感知、发射信号波形设计与优化、收发闭环联合自适应处理方法等关键问题，实现基于在线预测与知识辅助的低可探测目标检测，拟解决天波雷达系统性能受外部环境制约的瓶颈问题。预期研究成果有助于提升天波雷达低可探测目标的检测性能，拓展同时执行多任务的功能，丰富发展中的认知雷达应用基础理论，因而具有重要的理论价值和广阔的应用前景。

二维收发阵列、多输入多输出（MIMO）雷达体制是新一代认知天波超视距雷达（CSWOTHR）系统的扩展与延伸，该系统兼备认知技术、MIMO技术和俯仰波束控制能力，有助于解决传统天波超视距雷达（OTHR）存在的电离层污染与复杂环境对低可探测目标检测带来的瓶颈问题。本项目瞄准以二维收发阵列、MIMO体制为特点的新一代CSWOTHR，研究系统架构、波形设计、电离层污染校正、空中与海面低可探测目标检测方法，取得如下研究成果：（1）设计了感知与探测一体化的CSWOTHR系统架构，分析了系统知识辅助功能和高频信息实时感知机制，并说明CSWOTHR具有环境感知、智能化和接收-发射闭环信息处理结构等特点；（2）分析了天波雷达电离层污染模式，提出了考虑色散效应的空时频电离层精细结构模型，给出了电离层相位污染统一模型和知识辅助电离层污染校正方案，评估了典型电离层相位污染校正方法的综合性能；（3）设计了知识辅助自适应环境感知波形与MIMO-OTHR正交波形，提出了一种基于凸优化的二相编码失配滤波脉冲压缩方法和一种慢时间混沌随机相位编码波形；（4）针对低可探测空中弱目标检测难题，提出基于AR模型外推的OTHR短时探测方法和一种知识辅助动态规划检测前跟踪（KADP-TBD）方法；针对低可探测弹道导弹目标检测难题，提出OTHR弹道导弹尾焰凝聚快速检测方法；针对海杂波抑制和低可探测舰船目标检测难题，提出电离层子反射面模型的概念，揭示了相干处理间隔内电离层对高频信号频谱的调制机理，给出可以综合反映不同海态、不同电离层状态的OTHR海杂波修正模型，提出基于二维阵列波束形成的多模海杂波抑制方法、OTHR舰船目标最小可检测速度论证方法、基于压缩感知技术的短时海杂波抑制方法。促进了新一代认知天波超视距雷达低可探测目标检测方法的原理创新与应用基础理论研究进程。