Synthetic Aperture Radar Polarimetry

This book describes the application of polarimetric synthetic aperture radar to earth remote sensing based on research at the NASA Jet Propulsion Laboratory (JPL). This book synthesizes all current research to provide practical information for both the newcomer and the expert in radar polarimetry. The text offers a concise description of the mathematical fundamentals illustrated with many examples using SAR data, with a main focus on remote sensing of the earth.

The book begins with basics of synthetic aperture radar to provide the basis for understanding how polarimetric SAR images are formed and gives an introduction to the fundamentals of radar polarimetry. It goes on to discuss more advanced polarimetric concepts that allow one to infer more information about the terrain being imaged. In order to analyze data quantitatively, the signals must be calibrated carefully, which the book addresses in a chapter summarizing the basic calibration algorithms. The book concludes with examples of applying polarimetric analysis to scattering from rough surfaces, to infer soil moisture from radar signals.

Note From the Series Editor xi

Foreword xiii

Preface xv

Acknowledgments xvii

Authors xix

1. Synthetic Aperture Radar (SAR) Imaging Basics 1

1.1 Basic Principles of Radar Imaging 2

1.2 Radar Resolution 6

1.3 Radar Equation 10

1.4 Real Aperture Radar 11

1.5 Synthetic Aperture Radar 13

1.6 Radar Image Artifacts and Noise 16

1.7 Summary 22

References 22

2. Basic Principles of SAR Polarimetry 23

2.1 Polarization of Electromagnetic Waves 23

2.2 Mathematical Representations of Scatterers 27

2.3 Implementation of a Radar Polarimeter 32

2.4 Polarization Response 34

2.5 Optimum Polarizations 53

2.6 Contrast Enhancement 65

2.7 Summary 71

References 71

3. Advanced Polarimetric Concepts 73

3.1 Vector-Matrix Duality of Scatterer Representation 73

3.2 Eigenvalue- and Eigenvector-Based Polarimetric Parameters 76

3.3 Decomposition of Polarimetric Scattering 88

3.4 Image Classification 125

3.5 Polarimetric SAR Interferometry 135

3.6 Summary 141

References 141

4. Polarimetric SAR Calibration 145

4.1 Polarimetric Radar System Model 145

4.2 Cross Talk Estimation and Removal 152

4.3 Copolarized Channel Imbalance Calibration 161

4.4 Absolute Radiometric Calibration 166

4.5 Faraday Rotation 177

4.6 Summary 179

References 180

5. Applications: Measurement of Surface Soil Moisture 182

5.1 Surface Electrical and Geometrical Properties 183

5.2 Scattering from Bare Rough Surfaces 196

5.3 Example Bare Surface Soil Moisture Inversion Models 201

5.4 Comparison of the Performance of Bare Surface Inversion Models 211

5.5 Parameterizing Scattering Models 216

5.6 Inverting the IEM Model 222

5.7 Scattering from Vegetated Terrain 225

5.8 Simulation Results 239

5.9 Time Series Estimation of Soil Moisture 252

5.10 Summary 257

References 258

Appendixes

A. Tilted Small Perturbation Model Details 262

B. Bistatic Scattering Matrix of a Cylinder with Arbitrary Orientation 267

C. Nomenclature 276

Index 279

“It is also an ideal reference for radar remote sensing researchers, engineers and practitioners in the aerospace industry.” (Photogrammetric Engineering and Remote Sensing, 1 August 2013)

JAKOB van ZYL, PhD, has been with the NASA Jet Propulsion Laboratory since 1986. He has contributed to the design and development of many SAR systems, including SIR-C, SRTM, AIRSAR, TOPSAR, and GeoSAR. In 2010, he received the Distinguished Achievement Award from the Geoscience and Remote Sensing Society of the IEEE for his contributions to polarimatric SAR remote sensing. Dr. Jakob van Zyl is the associate director of Project Formulation and Strategy and NASA's Jet Propulsion Laboratory. Formerly, he was the director for JPL's Astronomy and Physics Directorate.

YUNJIN KIM, PhD, has been with the NASA Jet Propulsion Laboratory and¿California Institute of Technology since 1989. He has contributed to the development of several radar systems, such as SIR-C, AIRSAR, GeoSAR, and SRTM. Currently, Dr. Kim is the Nuclear Spectroscopic Telescope Array (NuSTAR) project manager. He is the author of two book chapters, more than twenty peer-reviewed articles, and more than seventy conference publications.

The first book to describe the process of deriving geophysical information from polarimetric radar measurements systematically

Based on several decades of research conducted at the NASA Jet Propulsion Laboratory, Synthetic Aperture Radar Polarimetry describes the application of polarimetric synthetic aperture radar (SAR) to Earth remote sensing. This book synthesizes all current research to provide practical information for both the newcomer and the expert in radar polarimetry. The text offers a concise description of the mathematical fundamentals illustrated with many examples using SAR data, with a main focus on remote sensing of the Earth.

The book begins with basics of synthetic aperture radar to provide the basis for understanding how polarimetric SAR images are formed and gives an introduction¿to the fundamentals of radar polarimetry. It goes on to discuss more advanced polarimetric concepts that allow one to infer more information about the terrain being imaged. In order to analyze data quantitatively, the signals must be calibrated carefully, which is addressed in a chapter that summarizes the basic calibration algorithms. The book concludes with an example of applying polarimetric analysis to scattering from rough surfaces in order to infer soil moisture from radar signals.

Many of the concepts presented in this book were pioneered by the authors, for which they are recognized across the globe. The book also introduces new concepts that enhance the interpretation of polarimetric SAR data, as well as several concepts that are not covered in any current volumes on polarimetric SAR—for example, an extensive treatment of the techniques used to calibrate polarimetric SAR data is provided. Several of the algorithms presented here were originally developed by the authors, and the algorithms are illustrated with actual SAR data.

With a unique emphasis on practical applications, Synthetic Aperture Radar Polarimetry can be used as a textbook for a graduate class. It is also an ideal reference for radar remote sensing researchers, engineers, and practitioners in¿the aerospace industry.