基于双线性扩展分数傅里叶变换的 SAR 图像中非均匀旋转舰船再聚焦

Nonuniformly-Rotating Ship Refocusing in SAR Imagery Based on the Bilinear Extended Fractional Fourier Transform.

机构信息

Space Microwave Remote Sensing System, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.

School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100039, China.

出版信息

Sensors (Basel). 2020 Jan 19;20(2):550. doi: 10.3390/s20020550.

DOI:10.3390/s20020550

PMID:31963950

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC7014478/

Abstract

Nonuniformly-rotating ship refocusing is very significant in the marine surveillance of satellite synthetic aperture radar (SAR). The majority of ship imaging algorithms is based on the inverse SAR (ISAR) technique. On the basis of the ISAR technique, several parameter estimation algorithms were proposed for nonuniformly rotating ships. But these algorithms still have problems on cross-terms and noise suppression. In this paper, a refocusing algorithm for nonuniformly rotating ships based on the bilinear extended fractional Fourier transform (BEFRFT) is proposed. The ship signal in a range bin can be modeled as a multicomponent cubic phase signal (CPS) after motion compensation. BEFRFT is a bilinear extension of fractional Fourier transform (FRFT), which can estimate the chirp rates and quadratic chirp rates of CPSs. Furthermore, BEFRFT has excellent performances on cross-terms and noise suppression. The results of simulated data and Gaofen-3 data verify the effectiveness of BEFRFT.

摘要

非匀速旋转船舶重聚焦在卫星合成孔径雷达（SAR）的海洋监测中非常重要。大多数船舶成像算法都是基于逆合成孔径雷达（ISAR）技术。在 ISAR 技术的基础上，提出了几种用于非匀速旋转船舶的参数估计算法。但这些算法在交叉项和噪声抑制方面仍存在问题。本文提出了一种基于双线性扩展分数阶傅里叶变换（BEFRFT）的非匀速旋转船舶重聚焦算法。运动补偿后，距离单元中的船舶信号可建模为多分量立方相位信号（CPS）。BEFRFT 是分数阶傅里叶变换（FRFT）的双线性扩展，它可以估计 CPS 的线性调频斜率和二次调频斜率。此外，BEFRFT 在交叉项和噪声抑制方面具有优异的性能。仿真数据和高分三号数据的结果验证了 BEFRFT 的有效性。