低掠射微波雷达的海杂波多方位幅度特性分析

Multi-azimuth Amplitude Analysis of Sea Clutter At Low Grazing Angle

雷达处于低掠射角探测时,干涉、衍射以及遮挡等效应导致电磁波与海面的相互作用更加复杂,海杂波的非均匀、非高斯、非线性特性明显,使得海杂波建模难度大,同时,雷达海杂波在多方位下的特性是否存在差异也是一个问题,进一步增大了低掠射条件下海杂波的认知难度。为了提高海杂波的建模精度和多方位特性的认知,亟需开展低掠射雷达海杂波的多方位幅度特性分析。利用低掠射机载雷达数据,围绕雷达的低掠射和多方位两个特点,开展了多方位海杂波的幅度特性差异分析,在此基础上,利用多个海杂波模型对低掠射、多方位下的海杂波进行拟合优度分析。实现了低掠射角条件下海杂波的多方位特性差异认知,包括不同方位下的带宽和最优海杂波模型。实验结果表明,雷达前视状态带宽最窄,侧视最宽;对于多方位下的最优海杂波拟合,雷达前视时推荐G^0分布,而侧视模式下,海杂波更接近K和GΓD分布。

At low grazing angle,the interaction of electromagnetic wave and the sea surface is more complex due to the interference,diffraction and shade effect.The non-uniform,non-Gaussian and nonlinear characteristics of sea clutter make it difficult to model.Furthermore,the characteristic difference of radar sea clutter under multi-azimuth angle increase the cognitive difficulty.To better understand sea clutter,multi-azimuth amplitude analysis of sea clutter was carried out at low grazing angle by using the airborne radar data.On the basis,the goodness of fit of sea clutter models was analyzed at different azimuth angles.The results show that the bandwidth is the narrowest at forward-looking and widest at side-looking.For multi-azimuth sea clutter modeling,G^0 distribution is recommended in forward-looking,and K and GΓD are recommended in side-looking.