Bistatic Synthetic Aperture Radar

By Jianyu Yang

Bistatic Synthetic Aperture Radar covers bistatic SAR in a comprehensive way, presenting theory, method and techniques, as well as the most recent research and near-future applications. The book begins with imaging principles and characteristics of monostatic SAR, moving on to common and novel problems before presenting theories, methods and experimental system design. The title presents the design of experimental systems, research results and experimental verification. It gives key knowledge from a leading research group, including one of the earliest bistatic side-looking SAR experiments and the first bistatic forward-looking SAR experiment in the world that used two aircraft.

Six chapters cover imaging theory, imaging algorithms, parameter estimation, motion compensation, synchronization and experimental verification. The book describes physical concepts simply and clearly and provides concise mathematical derivations.

• Presents comprehensive theory and methods for bistatic SAR, including the design of experimental systems and verification
• Considers different configurations, including translational variant bistatic SAR and bistatic forward-looking SAR
• Gives insights based on a world-leading research program into bistatic SAR, including practical tips on theory and method
• Covers novel experiments, including the first bistatic forward-looking SAR experiment using two aircraft
• Offers researchers clear descriptions of physical concepts and concise mathematical derivations to help master bistatic SAR

• Language: English
• Publisher: Elsevier Science
• Release date: Jan 20, 2022
• ISBN: 9780128224601

Jianyu Yang

Professor at the University of Electronic Science and Technology of China (UESTC). He has also been a senior visiting scholar at MIT in the USA, and is a Fellow of the Chinese Institute of Electronics. He received his PhD from UESTC. His research covers 30 years, focusing on Synthetic Aperture Radar (SAR), particularly bistatic SAR, with a number of milestones achieved. In 2007 he conducted the first airborne bistatic side-looking SAR imaging experiment in China, and in 2012 obtained the first bistatic forward-looking SAR image in the world. He has published widely and is considered a leading expert in the field.

Book preview

Preface

Jianyu Yang, University of Electronic Science and Technology of China, Chengdu, People's Republic of China

Synthetic aperture radar (SAR) has the ability of all-day and all-weather high-resolution terrain imaging, and is one of the main technologies for Earth observations. Even in recent years, SAR is still constantly improving and evolving into different forms. Among them, bistatic SAR, boasting its unique antiinterference and forward-looking ability, is one of the most striking evolved forms, and is moving from research and verification to applications, becoming an important branch of SAR.

Compared with monostatic SAR, bistatic SAR, whose transmitter and receiver are mounted on different platforms, has more degrees of freedom and its echo law presents new features, causing bistatic SAR to face complex new problems in synchronization, imaging, and compensation. Although the concept of bistatic SAR was proposed as early as the 1970s, it developed slowly in the early stages. In recent decades, driven by application demand, coupled with the advancements in relevant technologies, bistatic SAR has been developing rapidly. Deeper and more comprehensive understandings about bistatic SAR than those in existing books are scattered in many different research papers. To avoid the huge time and effort needed to acquire this new knowledge from varied sources, a new book about bistatic SAR needs to be written.

The research team under my leadership has carried out long-term and extensive research on bistatic SAR. In 2007, we conducted successfully China's first airborne bistatic SAR imaging experiment, working in side-looking mode, and in 2012, we obtained the first airborne bistatic forward-looking SAR image. In 2020, we realized not only the spaceborne-airborne bistatic forward-looking SAR, but also the bistatic forward-looking SAR-GMTI for the first time in the experiment. It is because of the experience in leading and participating these research that I was able to write such a book to comprehensively present the relevant theories, methods, and techniques involved in bistatic SAR. The contents of the book are divided into seven chapters, including an introduction and chapters on imaging theories, imaging algorithms, parameter estimation, motion compensation, bistatic synchronization, and experiment verification.

This book includes not only necessary and practical theories and methods involved in bistatic SAR, but also the design of experimental systems and the results of experimental verifications, etc. In addition, this book reports the latest research results and the potential development of bistatic SAR, involving many useful processing algorithms for bistatic SAR with different configurations, such as translational variant bistatic SAR, bistatic forward-looking SAR, among others.

As a new kind of SAR system that is being studied and tested, there are still a lot of aspects that needs to be investigated and improved for bistatic SAR. Hence, there are inevitably shortcomings and mistakes in the book, and your suggestions would be appreciated.

Chapter 1: Overview of bistatic SAR

Abstract

Because the transmitter and receiver in bistatic SAR systems are carried on different platforms, bistatic SAR has a series of problems in imaging theory, system composition, transceiver synchronization, parameter estimation, motion compensation, imaging processing, and experimental verification. This chapter elaborates on the imaging principle, system classification, system composition, performance parameters, research status, and development trends of bistatic SAR from the perspective of the spatial relationship and physical concept. It briefly analyzes the similarities and differences between bistatic SAR and monostatic SAR, and then puts forward the theoretical and technical issues that need attention. A more detailed discussion will be carried out in the following chapters.

Keywords

Synthetic aperture radar; Bistatic SAR; SAR configuration classification; SAR system composition; SAR performance parameters; SAR imaging characteristics

Synthetic aperture radar (SAR) uses microwave transmitting and receiving devices carried on a moving platform to obtain scattering echoes of ground objects from different observation angles, and then carries out echo data processing through a signal processing device to obtain the estimated value of the distribution function of the microwave scattering rate of ground objects, so as to achieve ground imaging.

The SAR system can use the intensity of the echo signal to distinguish various types of ground objects with different scattering rates, and then achieve radiation resolution. Using the pulse compression of wideband signals, the equivalent narrow pulse is formed to realize the range resolution. A large antenna aperture is synthesized by using the change of viewing angle generated by motion to realize the azimuth resolution. By using the phase interferometrics of multichannel echo, the difference of wave path between channels can be used to obtain height measurement. Based on the difference of frequency and polarization response of the scattering rate, the features of the ground object are extracted to realize the material resolution. The active microwave radiation of the radar transmitter is used to illuminate the observed ground object features for operation both day and night. Based on the characteristics of electromagnetic wave propagation in the microwave frequency band, through the clouds, rain, fog, foliage, and ground, penetrating observation can be realized. Therefore the SAR system can obtain planar, black-and-white, and even stereo and color images of ground objects. It has all-day, all-weather, high-resolution, and multidimensional earth observation and imaging capabilities. It has been widely used in civil and military applications and is an indispensable means of earth