A Two-Step Motion Compensation Method for Polar Format Images of Terahertz SAR Based on Echo Data

IF 4.7 2区地球科学 Q1 ENGINEERING, ELECTRICAL & ELECTRONIC

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Pub Date : 2024-09-13 DOI:10.1109/JSTARS.2024.3461332

Shaowen Luo;Qiuyan Wang;Yinwei Li;Xiaolong Chen;Yiming Zhu

{"title":"A Two-Step Motion Compensation Method for Polar Format Images of Terahertz SAR Based on Echo Data","authors":"Shaowen Luo;Qiuyan Wang;Yinwei Li;Xiaolong Chen;Yiming Zhu","doi":"10.1109/JSTARS.2024.3461332","DOIUrl":null,"url":null,"abstract":"Terahertz synthetic aperture radar (THz SAR) has great potential in the field of remote sensing due to its high resolution and high frame rate. However, THz SAR is very sensitive to motion errors, making even small 2-D error caused by motion error and polar format algorithm (PFA) seriously affect the image quality. Existing microwave SAR autofocusing methods only estimate the error of a single dimension, which cannot meet the accuracy requirements of THz SAR for 2-D error compensation. In this article, a two-step motion compensation method for polar format images of THz SAR based on echo data is proposed. First, by analyzing the conversion model of polar coordinate format, the node where the 2-D error coupling occurs is determined. On this basis, a coarse compensation based on low-frequency fitting is proposed in front of this node to reduce the influence of PFA on the error coupling of 2-D signals. The method not only preserves the correction of the inherent range cell migration by PFA but also eliminates the interference of PFA to the subsequent error compensation processing. Second, to solve the problem that a single compensation method cannot meet the accuracy requirements of THz SAR, the maximum contrast method after polar coordinate format conversion is used for precision compensation. The effectiveness of the proposed method is verified through simulation and actual measurement data processing of 0.22-THz airborne spotlight SAR system.","PeriodicalId":13116,"journal":{"name":"IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing","volume":null,"pages":null},"PeriodicalIF":4.7000,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10680337","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing","FirstCategoryId":"5","ListUrlMain":"https://ieeexplore.ieee.org/document/10680337/","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}

引用次数: 0

Abstract

Terahertz synthetic aperture radar (THz SAR) has great potential in the field of remote sensing due to its high resolution and high frame rate. However, THz SAR is very sensitive to motion errors, making even small 2-D error caused by motion error and polar format algorithm (PFA) seriously affect the image quality. Existing microwave SAR autofocusing methods only estimate the error of a single dimension, which cannot meet the accuracy requirements of THz SAR for 2-D error compensation. In this article, a two-step motion compensation method for polar format images of THz SAR based on echo data is proposed. First, by analyzing the conversion model of polar coordinate format, the node where the 2-D error coupling occurs is determined. On this basis, a coarse compensation based on low-frequency fitting is proposed in front of this node to reduce the influence of PFA on the error coupling of 2-D signals. The method not only preserves the correction of the inherent range cell migration by PFA but also eliminates the interference of PFA to the subsequent error compensation processing. Second, to solve the problem that a single compensation method cannot meet the accuracy requirements of THz SAR, the maximum contrast method after polar coordinate format conversion is used for precision compensation. The effectiveness of the proposed method is verified through simulation and actual measurement data processing of 0.22-THz airborne spotlight SAR system.

查看原文本刊更多论文

基于回波数据的太赫兹合成孔径雷达极坐标图像两步运动补偿法

太赫兹合成孔径雷达（THz SAR）具有高分辨率和高帧频，在遥感领域具有巨大潜力。然而，太赫兹合成孔径雷达对运动误差非常敏感，即使是由运动误差和极化格式算法（PFA）引起的微小二维误差也会严重影响图像质量。现有的微波合成孔径雷达自动聚焦方法只能估计单维误差，无法满足太赫兹合成孔径雷达对二维误差补偿的精度要求。本文提出了一种基于回波数据的太赫兹合成孔径雷达极格式图像两步运动补偿方法。首先，通过分析极坐标格式的转换模型，确定发生二维误差耦合的节点。在此基础上，针对该节点提出了基于低频拟合的粗补偿方法，以减少 PFA 对二维信号误差耦合的影响。该方法不仅保留了 PFA 对固有量程单元迁移的修正，还消除了 PFA 对后续误差补偿处理的干扰。其次，为解决单一补偿方法无法满足太赫兹合成孔径雷达精度要求的问题，采用极坐标格式转换后的最大对比度法进行精度补偿。通过对 0.22-THz 机载聚光合成孔径雷达系统的仿真和实际测量数据处理，验证了所提方法的有效性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 地学-成像科学与照相技术

CiteScore

9.30

自引率

10.90%

发文量

563

审稿时长

4.7 months

期刊介绍： The IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing addresses the growing field of applications in Earth observations and remote sensing, and also provides a venue for the rapidly expanding special issues that are being sponsored by the IEEE Geosciences and Remote Sensing Society. The journal draws upon the experience of the highly successful “IEEE Transactions on Geoscience and Remote Sensing” and provide a complementary medium for the wide range of topics in applied earth observations. The ‘Applications’ areas encompasses the societal benefit areas of the Global Earth Observations Systems of Systems (GEOSS) program. Through deliberations over two years, ministers from 50 countries agreed to identify nine areas where Earth observation could positively impact the quality of life and health of their respective countries. Some of these are areas not traditionally addressed in the IEEE context. These include biodiversity, health and climate. Yet it is the skill sets of IEEE members, in areas such as observations, communications, computers, signal processing, standards and ocean engineering, that form the technical underpinnings of GEOSS. Thus, the Journal attracts a broad range of interests that serves both present members in new ways and expands the IEEE visibility into new areas.