摘要:
蒸发波导是一种在海面上频繁出现的多径传播环境，会引起信号畸变，导致常规算法分辨率下降，使得雷达测向测距误差加大甚至无法工作.本文提出了一种基于方向图加载的时间反演抛物方程定位算法，能够有效地处理蒸发波导效应，自适应地补偿信号畸变，形成与传播环境相匹配的、经过时间反演的电波，从而稳健地实现对目标的聚焦定位.该算法能够巧妙地利用多径效应，增大天线阵列的有效口径，得到超分辨率的效果.另外，它还对阵元间距有着较高的宽容性，这样就可以采用稀布形式，从而提高算法的实用性，增加其适用范围.仿真结果表明，对于相同口径的阵列天线，该算法使方位分辨率较自由空间提高了2倍以上；在30λ的大阵元间距下，旁瓣电平在8.96 dB以下，有效地抑制了鬼像的产生.该算法具有较强的稳健性和较高的精度，在海面通信、搜救、预警等领域有着广阔的应用前景.
Abstract:
Evaporation duct is a multipath environment on the sea, which tends to distort the signals, causes lower localization accuracy or even affects the normal work of radar when using the traditional localization algorithms. This paper presents a localization method in time reversal parabolic equation based on the radiation pattern loading. It could effectively handle the effects of evaporation duct and adaptively compensate the signal distortion, form time reversed waves matched with the propagation environment, and lead to a robust focusing and localization of the target. This method uses multipath effects flexibly to increase the effective aperture of antenna array for super resolution. In addition, it has a good tolerance in element spacing leading to a sparse array configuration which is more practical on the sea and widens its application fields. Simulation results show that the azimuth resolution in evaporation duct with the same aperture array has been improved 2 times more than in the free space by using this method; when 30λ is adopted as the element spacing, the sidelobe levels can be kept below?8.96 dB, so ghost images are effectively suppressed. The proposed method has strong robustness and high accuracy, thus may be useful in many practical applications, such as communication, search and rescue, pre-warning system on the sea, etc.
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