Target micromotion not only plays an important role in target recognition but also leads to esoteric characteristics in synthetic aperture radar （SAR） imaging. This paper finds out an interesting phenomenon, i.e. th...Target micromotion not only plays an important role in target recognition but also leads to esoteric characteristics in synthetic aperture radar （SAR） imaging. This paper finds out an interesting phenomenon, i.e. the angular extent effect, in micro-motion target images formulated by the polar format algorithm. A micromotion target takes on multiple pairs of paired echoes （PEs） around the true point, and each PE extends for an angle which is exactly equal to the angular extent of the synthetic aperture, regardless of the micromotion frequency. The effect is derived and interpreted by using the characteristics of Bessel functions. Then it is demonstrated by simulation experiments of a target with different micromotion frequencies. The revelation and interpretation of the effect is highly beneficial to micromotion-target SAR image understanding as wel as target recognition.展开更多
为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔...为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔径,利用PFA处理子孔径数据。由于PFA存在波前弯曲误差,子图像不能直接拼接,因此对每一幅子图像进行几何失真校正。同时,以重叠子孔径的划分方式保证成像结果的高分辨率。最后截取子图像进行拼接得到条带SAR成像结果。所提方法解决了车载毫米波雷达大斜视情况下两维耦合严重的问题。通过对点目标和实测数据的仿真与分析验证了所提方法的有效性。展开更多
基金supported by the National Natural Science Foundationof China(6130214861101182)
文摘Target micromotion not only plays an important role in target recognition but also leads to esoteric characteristics in synthetic aperture radar （SAR） imaging. This paper finds out an interesting phenomenon, i.e. the angular extent effect, in micro-motion target images formulated by the polar format algorithm. A micromotion target takes on multiple pairs of paired echoes （PEs） around the true point, and each PE extends for an angle which is exactly equal to the angular extent of the synthetic aperture, regardless of the micromotion frequency. The effect is derived and interpreted by using the characteristics of Bessel functions. Then it is demonstrated by simulation experiments of a target with different micromotion frequencies. The revelation and interpretation of the effect is highly beneficial to micromotion-target SAR image understanding as wel as target recognition.
文摘为了应对车载毫米波雷达大斜视成像困难的问题,本文提出一种改进的极坐标格式算法(Polar Format Algorithm,PFA)对条带车载毫米波雷达斜视回波进行基于子孔径拼接的成像。该算法从条带数据与聚束数据的特点出发,将全孔径回波划分为子孔径,利用PFA处理子孔径数据。由于PFA存在波前弯曲误差,子图像不能直接拼接,因此对每一幅子图像进行几何失真校正。同时,以重叠子孔径的划分方式保证成像结果的高分辨率。最后截取子图像进行拼接得到条带SAR成像结果。所提方法解决了车载毫米波雷达大斜视情况下两维耦合严重的问题。通过对点目标和实测数据的仿真与分析验证了所提方法的有效性。
