Bistatic SAR Data Processing Algorithms E-Book

Xiaolan Qiu

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 429

Veröffentlichungsjahr: 2013

Beschreibung

BISTATIC SAR DATA PROCESSING ALGORITHMS

Synthetic Aperture Radar (SAR) is critical for remote sensing. It works day and night, in good weather or bad. Bistatic SAR is a new kind of SAR system, where the transmitter and receiver are placed on two separate platforms. Bistatic SAR is one of the most important trends in SAR development, as the technology renders SAR more flexible and safer when used in military environments. Imaging is one of the most difficult and important aspects of bistatic SAR data processing. Although traditional SAR signal processing is fully developed, bistatic SAR has a more complex system structure, so signal processing is more challenging. Focusing on imaging aspects of bistatic SAR signal processing, this book covers resolution analysis, echo generation methods, imaging algorithms, imaging parameter estimation, and motion compensation methods.

• Gives a general and updated framework for image formation using signal processing aspects
• Starts with an introduction to traditional SAR before moving on to more advanced topics
• Offers readers a range of exhaustive tools to process signals and form images
• Provides a solid reference for the imaging of other complicated SAR
• MATLAB® codes are available from the book’s companion site

The book is ideal for researchers and engineers in SAR signal and data processing, as well as those working in bistatic and multistatic radar imaging, and in the radar sciences. Graduate students with a background in radar who are interested in bistatic and multistatic radar will find this book a helpful reference.

Leseprobe

Contents

Cover

Title Page

Copyright

About the Authors

Preface

Acknowledgements

List of Acronyms

Chapter 1: Introduction

1.1 Overview of SAR Development

1.2 Brief Introduction of Bistatic SAR

1.3 Contents of the Book

References

Chapter 2: Signal Processing Basis of SAR

2.1 Range Resolution of SAR

2.2 Azimuth Resolution of SAR

2.3 SAR Resolution Cell

2.4 SAR Processing Model – Single-Point Target Imaging

2.5 Brief Introduction to Efficient SAR Imaging Algorithms

2.6 Summary

References

Chapter 3: Basic Knowledge of Bistatic SAR Imaging

3.1 Bistatic SAR Configurations

3.2 Radar Equation of Bistatic SAR

3.3 Spatial Resolution of Bistatic SAR

3.4 Summary

References

Chapter 4: Echo Simulation of Bistatic SAR

4.1 Introduction

4.2 Traditional Monostatic SAR Raw Data Simulation

4.3 Raw Data Simulation for Translational Invariant Bistatic SAR

4.4 Summary

References

Chapter 5: Imaging Algorithms for Translational Invariant Bistatic SAR

5.1 Introduction

5.2 Imaging Algorithms Based on Monostatic Transform

5.3 Imaging Algorithms Based on Range History Simplification

5.4 Imaging Algorithms Based on Analytical Explicit Spectrums

5.5 Imaging Algorithms Based on Accurate Implicit Spectrums

5.6 Comparison of the Algorithms

5.7 Summary

References

Chapter 6: Imaging Algorithm for Translational Variant Bistatic SAR

6.1 Introduction

6.2 Imaging Algorithms for One-Stationary Bistatic SAR

6.3 Imaging Algorithms for Translational Variant Bistatic SAR with Constant Velocities

6.4 Summary

References

Chapter 7: Bistatic SAR Parameter Estimation and Motion Compensation

7.1 Introduction

7.2 Analyzing the Effects of Motion Errors

7.3 Estimation of Doppler Parameters

7.4 Principle and Methods of SAR Motion Compensation

7.5 Summary

References

Index

This edition first published 2013 © 2013 Science Press. All rights reserved.

Published by John Wiley & Sons Singapore Pte. Ltd., 1 Fusionopolis Walk, #07-01 Solaris South Tower, Singapore 138628, under exclusive license by Science Press in all media and all languages throughout the world excluding Mainland China and excluding Simplified and Traditional Chinese languages.

For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com.

All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as expressly permitted by law, without either the prior written permission of the Publisher, or authorization through payment of the appropriate photocopy fee to the Copyright Clearance Center. Requests for permission should be addressed to the Publisher, John Wiley & Sons Singapore Pte. Ltd., 1 Fusionopolis Walk, #07-01 Solaris South Tower, Singapore 138628, tel: [phone], fax: [phone], email: [email protected].

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The Publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the Publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought.

MATLAB® is a trademark of The MathWorks, Inc. and is used with permission. The MathWorks does not warrant the accuracy of the text or exercises in this book. This book's use or discussion of MATLAB® software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB® software.

Library of Congress Cataloging-in-Publication Data

Qiu, Xiaolan. Bistatic SAR data processing algorithms / Xiaolan Qiu, Chibiao Ding, and Donghui Hu. pages cm Includes bibliographical references and index. ISBN 978-1-118-18808-8 (hardback) 1. Bistatic radar. 2. Signal processing. 3. Synthetic aperture radar. 4. Algorithms. I. Ding, Chibiao. II. Hu, Donghui. III. Title. TK6592.B57Q58 2013 621.3848′5–dc23 2012050150

About the Authors

Xiaolan Qiu received her B.S. degree in electronic engineering from the University of Science and Technology of China (USTC) in 2004 and a Ph.D. degree in signal and information processing from the Graduate University of the Chinese Academy of Sciences (GUCAS), Beijing, China, in 2009.

While working towards her Ph.D. degree, she was working as an intern in the Institute of Electronics, Chinese Academy of Sciences (IECAS) (website: www.ie.cas.cn) and worked on the IECAS bistatic SAR program. Her Ph.D. thesis was ‘Research on Precise Imaging Algorithms for Bistatic SAR’, and she won the Special Prize of President of The Chinese Academy of Sciences (the highest honor of GUCAS and only 20 winners in China per year) as a Ph.D. candidate in 2009 on this subject. She was then nominated to be a member of the Youth Innovation Promotion Association of CAS, which gives young researchers financial support for their studying, researching and communicating with other researchers.

After obtaining her Ph.D. degree, she joined IECAS and became a member of the SAR group in the Key Laboratory of Technology in Geo-spatial Information Processing and Application System (GIPAS), Chinese Academy of Sciences (CAS). In IECAS-GIPAS, Xiaolan Qiu was involved in developing processors for IECAS's airborne SARs and also for the Chinese Remote Sensing Satellites. From May to October 2011, she was supported by K.C. Wong Education Foundation, Hong Kong and being a guest scientist in the Center for Sensorsystems (ZESS), University of Siegen. Her current research interests include bistatic SAR, SAR interferometry and SAR simulation.

Chibiao Ding received his B.S. and Ph.D. degrees in electronic engineering from Beihang University, Beijing, China, in 1991 and 1997, respectively.

Since then, he has been working with the Institute of Electronics, Chinese Academy of Sciences “IECAS”. In IECAS, he has taken charge of a number of significant projects in China, including the first high-resolution spotlight airborne SAR system and the first airborne InSAR system of China, and the remote sensing satellite data processing and application system. For his excellent work, he won the National Prize for Progress in Science and Technology of China (the first prize in 2006) and the National Youth Science and Technology Award (2007).

Chibiao Ding is currently a Research Fellow and the Vice Director of IECAS. His research interests include advanced SAR (including bistatic SAR, GeoSAR, MIMO SAR) data processing and application.

Donghui Hu received his B.S. degree from Peking University, Beijing, China, in 1992, and the M.S. degree from the Beijing Institute of Technology, Beijing, in 2001.

Since then, he has been with the Institute of Electronics, Chinese Academy of Sciences, where he has been involved in airborne and spaceborne SAR data processing and became a senior expert in this area. As a main contributor, he successfully developed the simulation and calibration software for the first remote sensing satellite of China. As the technical supervisor, he processed the data of IECAS's airborne InSAR and produced DSM with very high precision. Because of his contribution, he won the second prize of Scientific and Technological Progress Awards.

His current research interests include bistatic SAR data processing, SAR interferometry, geostationary orbit SAR data processing and radar moving target identification.

Preface

The synthetic aperture radar (SAR) is a microwave imaging radar that achieves high resolution while taking advantage of pulse compression technology and the Doppler effect. The SAR technology has made progress for over 60 years since the idea of a synthetic aperture was proposed by Wiley in 1951. Nowadays, SAR is widely used in environment protection, disaster detection, ocean observation, resource exploiting, agriculture, forest, space and aerial reconnaissance, and so on. SAR can work in an all-weather condition, day and night, and so is irreplaceable in these areas. As technology progresses, SAR is now desired to achieve improved capabilities, for example, higher resolution combined with a wider swath, multipolarization, three-dimensional resolution and so on. For some of these capabilities, the traditional monostatic SAR system has its limitations. Therefore, bi- and multistatic SAR systems become one of the important trends of SAR development. Therein, bistatic SAR has been paid a lot of attention all over the world since the start of the 21st century.

Data processing is one of the key problems and also a difficulty of bistatic SAR. Quite a lot of work has been done on this topic in the last decade. Especially on the topic of bistatic SAR imaging, many new imaging theories and imaging methods have been proposed. Though bistatic SAR imaging has not achieved its mature stage, the authors think the research on bistatic SAR imaging has been quite fruitful and could be used for reference to the data processing of other advanced SAR systems. To the authors' knowledge, there has not been any book in China that is special to bistatic SAR imaging or that summarizes the research results on bistatic SAR imaging, so they have tried to do this job based on work on bistatic SAR in their laboratories. The authors hope their work could be a help to those working on advanced SAR data processing. Therefore, in April 2010, the authors' book titled Bistatic SAR Imaging Technology (in Chinese) was published by the Science Press. After that, they were lucky to get the chance to publish their work in an English version by John Wiley & Sons Singapore Pte. Ltd, so they translated the Chinese book and also added some new achievements on bistatic SAR imaging.

The authors are in two laboratories hosted by the Institute of Electronics, Chinese Academy of Sciences (IECAS): Key Laboratory of Technology in Geo-spatial Information Processing and Application Systems (GIPAS) and The National Key Laboratory of Science and Technology on Microwave Imaging (MITL). In 2003, one of the authors attended the International Geoscience and Remote Sensing Symposium (IGARSS) and was inspired and got the idea to build a bistatic SAR receiver. It was decided that they would carry out bistatic SAR experiments combined with the airborne SAR at MITL, which is called the IECAS SAR, and exploit its potential applications. Then, GIPAS began to do research on bistatic SAR data processing and MITL began to study the bistatic synchronization methods. After about one year of research, MITL succeeded in obtaining funding to build a passive receiver. They started to design and construct the receiver and some indoor experiments were carried out. GIPAS was responsible for processing the experimental data. The bistatic SAR project was suspended for a time as an airborne InSAR project was considered to have priority. As a result, the first airborne–ground bistatic SAR experiment was not carried out until July 2011 and the first bistatic SAR image of IECAS was generated then. Between May 2011 and November 2011, the first author was at the Center for Sensor Systems (ZESS) hosted by the University of Siegen as a visiting scientist by the support of the K.C. Wong Education Foundation of the Chinese Academy of Sciences. In ZESS, she had the chance to process the bistatic SAR experimental data, including airborne bistatic SAR data and satellite–ground one-stationary bistatic SAR data. She verified some of the algorithms the authors had proposed using these data.

The authors wrote this book based on their work on bistatic SAR at MITL and GIPAS for about ten years. This book starts with a brief introduction of bistatic SAR and then provides the resolution theory and classical imaging algorithms for traditional monostatic SAR to be set as a basis. The bistatic SAR resolution is then analyzed in detail and echo simulation methods are discussed. Based on this, we get to the bistatic SAR imaging algorithms. They are categorized into algorithms for a translational invariant bistatic SAR configuration and algorithms for a translational variant configuration. The algorithms are further sorted by their basic idea in each category. Finally, parameter estimation and motion compensation methods closely related to image formation are introduced.

This book can be a reference for researchers and engineers who work on SAR data processing, especially on advanced SAR data processing. Also, it can be helpful to postgraduate students who are beginners on SAR data processing.

As mentioned above, though the authors try to make a summary of bistatic SAR imaging algorithms, this book is mainly based on their own work. Therefore, the authors' work is described in detail, while the work of others is only briefly introduced. The categorizing of the algorithms represents the authors' own opinion and they would be very grateful to have different opinions brought to their attention. The authors apologize in advance for any errors that may be present in the book and would be very grateful to have them brought to their attention.

Acknowledgements

We would like to acknowledge three groups of people who have been very important to this book.

Firstly, we would like to thank those people who have supported and supervised our work. We would like to thank Academician YiRong Wu, who is the director of IECAS, for the kind guidance and the financial support. We also would like to thank Prof. Wen Hong and Prof. XingDong Liang, who are the directors of MITL, and Prof. Kun Fu and Prof. Bin Lei, who are the directors of GIPAS, for their trust and support. In addition, we thank very much the KC Wong Education Foundation of the Chinese Academy of Sciences for supporting the first author to go aboard and work at ZESS, hosted at the University of Siegen. We thank very much Prof. Dr.-Ing. habil. Otmar Loffeld, who is the Speaker and Chairman of ZESS, for accepting the first author as a visiting scientist to work at ZESS half a year and providing her the great chance to work with the SAR group in ZESS and gaining access to real bistatic SAR data. Besides, we would like to thank Prof. Ian G. Cumming and Dr. Yew Lam Neo for their kind encouragement. Without all this support, the authors could not have realized the dream of publishing a book abroad.

Secondly, the authors would like to thank those people who made direct contributions to this book. Dr. LiJia Huang at GIPAS helped to write Section 5.3.3 of the book. Dr. Bin Han and Dr. DaDi Meng at GIPAS provided plenty of the material for Chapters 2 and 7. Liangjiang Zhou was in charge of taking the bistatic SAR experiment. SongYa xiong and Yanlei Li helped to process the IECAS's bistatic experimental data. FangFang Li and Wei Han helped to draw many of the figures in this book. We also thank other members of the SAR group at GIPAS; they are Yuxin Hu, Jiayin Liu, Lihua Zhong, Wenyi Zhang, Hui Zhang, Yueting Zhang and so on. We would like to give our special thanks to Prof. Loffeld at ZESS who helped us to revise the first chapter of this book and gave many valuable comments and made many helpful revisions. We would also like to thank all the SAR group members in ZESS; they are Dr. Holger Nies, Florian Behner, Simon Reuter, JinShan Ding, Wei Yao, Amaya Medrano Ortiz, Qurat Ul-Ann, Ashraf Samarah, Valerij Peters and the former member Robert Wang. The first author has benefited from the discussions with them. The authors would like to thank very much Prof. Jie Chen at Beihang University, Beijing, China, for the kind help with translating the first two chapters of this book from Chinese to English. We also would like to thank DangDang Zhang and Xue Lin at GIPAS for the translation of Chapters 3 and 7. Especially, we would like to thank GuiYing Wang, who is the director of the Information Technology Center hosted at IECAS, for her help with planning this book.

Finally, we would like to thank our families for their patience, support, tolerance, caring and all the things they have done for us.

List of Acronyms

APCantenna phase centerBITBeijing University of TechnologyBPback-projectionBPTRSbistatic point target reference spectrumCDEcorrelation Doppler estimatorCSchirp scalingCTcomputed tomographyDEMdigital elevation modelDFGGerman Research FoundationDInSARdifferential interferometric SARDLRGerman Aerospace CenterDMOdip-move-outDSRdouble square rootESAEuropean Space AgencyEUSAREuropean Conference on Synthetic Aperture RadarFFTfast Fourier transformFMCWfrequency modulation continuous waveHRTI-3high-resolution terrain information 3IDWinstantaneous Doppler wavenumberIECASInstitute of Electronics, Chinese Academy of SciencesIFFTinverse fast Fourier transformIGARSSInternational Geoscience and Remote Sensing SymposiumINSinertial navigation systemInSARinterferometric SARISLRintegrated sidelobe ratioJSTARSjoint surveillance target attack radar systemLBFLoffeld's bistatic formulaLFMlinear frequency modulatedMTImoving target indicationNLCSnonlinear chirp scalingNuSARnumerical SARPDphase differencePGAphase gradient autofocusPolInSARpolarimetric interferometric SARPolSARpolarimetric SARPOSPprinciple of stationary phasePRFpulse repetition frequencyPSLRpeak sidelobe ratioRADARradio detection and rangingRCMrange cell migrationRCMCrange cell migration correctionRCSradar cross-sectionRDrange-DopplerRMSroot mean squareROPErank one phase estimation3D SARthree-dimensional SARSAR/FTIsynthetic aperture/fixed target indicatorSIMUstrapdown inertia measuring unitSNRsignal-to-noise ratioSRCsecond range compressionSTFTshort-time Fourier transformTBPtime bandwidth productTI configurationtranslational invariant configurationTV configurationtranslational variant configurationUESTCUniversity of Electronic Science and Technology of ChinaWAS/MTIwide-area surveillance/moving target indicatorZESSCenter for Sensorsystems

1

Introduction

1.1 Overview of SAR Development

Radar is the acronym of “radio detection and ranging”. It intends to detect and identify targets through the properties of electromagnetic waves reflected from obstacles (targets). Radar can detect a wide variety of targets, ranging from buildings, roads, bridges, vehicles, aircrafts, ships and other man-made objects to the mountains, rivers, forests, deserts, sea and other natural landscape. Furthermore, radar can detect the existence of long-distance targets without having effects of meteorological factors, such as daylight, clouds and rain conditions. Because of these characteristics of radar, it has been increasingly becoming an important tool in the field of microwave remote sensing and has played an important role in all aspects of remote sensing applications since its appearance in World War II. The history of radar has a close relationship with military applications since its inception. The advantages of radar in the areas of battlefield reconnaissance, target surveillance, weapon guidance and other aspects of performance greatly stimulated the interest of major industrial powers to radar, and this became the driving force of radar technological advances after World War II. Synthetic Aperture Radar (SAR) is a new high-resolution radar system that appeared in this period [1–6].

1.1.1 The History of SAR Development

SAR is an active microwave imaging radar that can achieve two-dimensional high-resolution images. The concept of synthetic aperture was firstly proposed to improve the azimuth resolution of radar. Before the concept was promoted, the traditional airborne radar used real aperture to obtain the images of the ground, that is, to distinguish targets at different locations through the direction of a real antenna beam. There is an inherent defect in real aperture radar, which is that its azimuth resolution is related to the distance between the radar and target. Within the constraints of wavelength and antenna size, as the distance between the radar and target increases, the radar azimuth resolution decreases. In order to obtain a high-resolution image of long-distance targets, the antenna beam must be extremely narrow. However, a narrow beam pattern can only be formed by a large antenna. For an airborne imaging radar, the distance between the radar and target is usually from several tens of kilometers to a hundred kilometers; for a spaceborne imaging radar, the distance between the radar and target is up to several hundred kilometers. In this way, to achieve only tens of meters of the azimuth resolution, the required aperture of the radar antenna would be a few kilometers or even dozens of kilometers, which is impossible to achieve in practice.