西安电子科技大学学报

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一种加速时域成像算法及其自聚焦方法

曾乐天;梁毅;李震宇;怀园园;邢孟道   

  1. (西安电子科技大学 雷达信号处理国家重点实验室,陕西 西安 710071)
  • 收稿日期:2016-01-19 出版日期:2017-02-20 发布日期:2017-04-01
  • 作者简介:曾乐天(1988-), 男, 西安电子科技大学博士研究生, E-mail: zengletian@stu.xidian.edu.cn
  • 基金资助:

    海洋公益性行业科研专项经费资助项目(201405001);中央高校基本科研业务费专项资金资助项目(K5051302046);航空科学基金与航空电子系统射频综合仿真航空科技重点实验室联合资助项目(20132081011)

Accelerated time domain imaging algorithm and its autofocus approach

ZENG Letian;LIANG Yi;LI Zhenyu;HUAI Yuanyuan;XING Mengdao   

  1. (National Key Lab. of Radar Signal Processing, Xidian Univ., Xi'an
  • Received:2016-01-19 Online:2017-02-20 Published:2017-04-01

摘要:

针对机载合成孔径雷达的导航系统精度不足这一问题,提出了一种与自聚焦方法相结合的加速时域成像算法.通过引入全局虚拟极坐标系,构建出聚焦域和相位历程域之间的傅里叶变换对关系,并采用基于加权最小均方相位梯度自聚焦方法实现运动误差高精度补偿.该方法采用快速傅里叶变换实现子图像的融合过程,避免了耗时的二维插值操作,且易与高精度自聚焦算法相结合,提取信号中的残余运动误差并补偿,提高成像质量.

关键词: 合成孔径雷达, 加速时域成像算法, 傅里叶变换对, 加权最小均方相位梯度自聚焦

Abstract:

The measurement accuracy of a navigation system is inadequate for airborne synthetic aperture radar (SAR). This may seriously degrade the image quality. In this paper, we propose an accelerated time domain (ATD) imaging algorithm combined with the autofocus method. By introducing the global pseudo polar coordinate (GPPC), we construct the Fourier transform pair (FTP) relationship. Then, the weighted least square phase gradient autofocus (WLS-PGA) algorithm is adopted to implement accurate phase error compensation. This method uses fast Fourier transform to implement sub-image fusions instead of time-consuming two-dimensional interpolation. Also, it has good compatibility with the high-accuracy autofocus algorithm to estimate the residual motion errors within the radar echoes and to obtain a well-focused image.

Key words: synthetic aperture radar(SAR), accelerated time domain(ATD) imaging algorithm, Fourier transform pair(FTP), weighted least square phase gradient autofocus(WLS-PGA)