主被动宽带低空飞行昆虫监测雷达的杂波抑制机理研究

The detection of flying insect at low altitude is an important problem for the current study on insect radar. Low altitude as the main activity space of most flying insects is an important detecting area of insect radar. Those existing insect radar were usually disable to detect the flying insect at a lower altitude than one hundred meter.The wide-band radar have enough bandwidth for the detection of widespread different insect flying at low altitude. The low altitude objects such as flying birds, moving air, floating dust and telecommunications, can result in clutter of the radar echo signal. It makes the radar very difficult to detect insect. The research of suppressing clutter is important for the radar to work effectively. In order to cut the cost, the passive radar without expensive high power transmitter is adopted to promote the extensive use and improve the ratio of cost performance. The signal-to-noise ratio of the passive radar is generally low. It is much more difficult to detect the insects from the high power clutter. The study of clutter suppression based on the passive insect radar is very significative and challenging. By prevenient study, the scheme of monostatic and bistatic passive location was designed. The method based on block subspace projection and wavelet analysis with dummy frequency agility was proposed for clutter suppression. The technologies such as micro-doppler analysis, Principal Component Analysis (PCA) and harmonic radar technique, was used in accordance with specific conditions. The mechanism of clutter suppression based on the wide-band insect radar is expected to be formed by the study and be used for the insect detection, civilian fields, specifically in agriculture and forestry. In military field, the mechanism is helpful to provide important reference basis for detecting the enemy's aircraft flying at low altitude.

低空飞行昆虫的监测问题是当前昆虫雷达研究面临的重要问题。低空作为大多数飞行昆虫的主要活动区域，此区域处在现有窄带昆虫雷达的盲区范围内而无法监测，且为适应不同尺寸多种昆虫的监测，雷达应具有足够的带宽，因而需采用宽带雷达。低空区域宽带雷达易受飞鸟、气流、运动尘埃和电讯等杂波干扰，昆虫监测难度很大，必须有效抑制杂波，而鉴于性价比和推广应用的考虑，本课题拟用无源雷达省去昂贵的发射机降低成本，无源雷达通常杂波噪声功率较高信噪比很低，昆虫监测与杂波抑制难度更大，因此该研究虽符合现实需要却极具挑战性。本课题在类似报导和前期研究的基础上，设计单双站的无源监测方案，提出基于分块子空间投影、虚拟跳频与小波分析相结合的方法，引入微多普勒分析、主成分分析和谐波雷达技术等进行杂波抑制，形成宽带昆虫雷达的杂波抑制理论。此研究可望促进农林等民用领域的推广应用，为军事领域无源雷达防范敌方的低空侦查突袭提供重要的参考依据

低空飞行昆虫的监测问题是当前昆虫雷达研究面临的重要问题。低空作为大多数飞行昆虫的主要活动区域，此区域处在现有窄带昆虫雷达的盲区范围内而无法监测，且为适应不同尺寸多种昆虫的监测，雷达应具有足够的带宽，因而需采用宽带雷达。低空区域宽带雷达易受飞鸟、气流、运动尘埃和电讯等杂波干扰，昆虫监测难度很大，必须有效抑制杂波，而鉴于性价比和推广应用的考虑，本课题利用无源雷达省去昂贵的发射机降低成本，无源雷达通常杂波噪声功率较高信噪比很低，昆虫监测与杂波抑制难度更大，因此该研究虽符合现实需要却极具挑战性。本课题首先设计了一种可改变顶角和孔径的锥面阵，锥面阵采用半波长偶极子对数周期天线，通过滑槽结构调节可改变各阵元天线与中心的距离，形成二维平面上的不同半径的空心环；利用控制杆高低的调节来改变虚顶角的大小并实现顶角的连续可调，组成不同倾角的立体阵，从而总体上实现在固定基座上更多维地监测目标信息。其次，提出了可调节步长的多重信号分类算法，减小了运算量，根据精度要求更快更准确地搜索目标。第三，本课题在类似报导和前期研究的基础上，设计单双站的无源监测方案，引入微多普勒分析等方法进行杂波抑制研究，形成宽带昆虫雷达的杂波抑制理论。此研究可望促进农林等民用领域的推广应用，为军事领域无源雷达防范敌方的低空侦查突袭提供重要的参考依据。