相位梯度法计算近场角闪烁的解析式

An Analytic Expression for Computing Near Field Angular Glint by Phase Gradient Method

角闪烁作为重要的目标特征信号,对雷达系统的影响主要发生在目标近场,而目前的角闪烁预估大多基于远场假设,针对这一现实问题,提出了一种基于散射中心模型的近场角闪烁预估技术.首先基于散射中心模型表示近场散射,然后通过直接求解相位函数的空间导数,得到了近场条件下相位梯度法的严格解析式,最后结合末制导条件给出了相应的简化公式.结论表明:黄培康等人《雷达目标特征信号》一书中的相位梯度法仅是本文在特定极化方式下的远场近似,而且在末制导距离范围内,所给出的近似式具有良好的精度,这些结果为近场角闪烁预估及其特性研究提供了理论依据.

As an important signature of the radar target, the angular glint effects on radar system mainly arise at near field. However, the current prediction methods of angular glint are mostly based on the far field condition. This paper presents a prediction technique of near field angular glint based on the scatter-center model to solve this problem. F＇rrstly, the near field backscattering is represented based on scatter-center model. Then by solving the derivative of the backscattering phase vs. the position vector of the observer, including incident angles and range, we get the exact expression of angular glint at near field. Finally, the exact expression is approximated and simplified in the range of terminal guidance. The conclusions of the paper show that the expression by HUANG Pei-kang in the book ＇Radar Target Signatures＇ is the approximation of ours at far field under certain polarization,and that the simplified expression has a well precision in the range of terminal guidance. All these results provide the theoretical basis for the prediction of near field angular glint and its signature research.