Spotlight-Mode Synthetic Aperture Radar: A Signal Processing Approach: A Signal Processing Approach
Modern airborne and spaceborne imaging radars, known as synthetic aperture radars (SARs), are capable of producing high-quality pictures of the earth's surface while avoiding some of the shortcomings of certain other forms of remote imaging systems. Primarily, radar overcomes the nighttime limitations of optical cameras, and the cloud- cover limitations of both optical and infrared imagers. In addition, because imaging radars use a form of coherent illumination, they can be used in certain special modes such as interferometry, to produce some unique derivative image products that incoherent systems cannot. One such product is a highly accurate digital terrain elevation map (DTEM). The most recent (ca. 1980) version of imaging radar, known as spotlight-mode SAR, can produce imagery with spatial resolution that begins to approach that of remote optical imagers. For all of these reasons, synthetic aperture radar imaging is rapidly becoming a key technology in the world of modern remote sensing.
Much of the basic `workings' of synthetic aperture radars is rooted in the concepts of signal processing. Starting with that premise, this book explores in depth the fundamental principles upon which the spotlight mode of SAR imaging is constructed, using almost exclusively the language, concepts, and major building blocks of signal processing.
Spotlight-Mode Synthetic Aperture Radar: A Signal Processing Approach is intended for a variety of audiences. Engineers and scientists working in the field of remote sensing but who do not have experience with SAR imaging will find an easy entrance into what can seem at times a very complicated subject. Experienced radar engineers will find that the book describes several modern areas of SAR processing that they might not have explored previously, e.g. interferometric SAR for change detection and terrain elevation mapping, or modern non-parametric approaches to SAR autofocus. Senior undergraduates (primarily in electrical engineering) who have had courses in digital signal and image processing, but who have had no exposure to SAR could find the book useful in a one-semester course as a reference.
Why Read This Book
You will learn how spotlight-mode SAR imaging systems form high-resolution pictures and how practical signal-processing algorithms (range compression, azimuth focusing, backprojection) are derived and implemented. The book balances rigorous derivations with implementation-oriented discussion so you can translate theory into working image-formation pipelines for airborne and spaceborne sensors.
Who Will Benefit
Advanced graduate students, radar signal-processing engineers, and remote-sensing practitioners who need to design or implement spotlight SAR image-formation, motion compensation, and high-resolution processing chains.
Level: Advanced — Prerequisites: Undergraduate-level signals and systems (Fourier transforms, convolution), basic radar and electromagnetics concepts, linear algebra and calculus, and familiarity with MATLAB or equivalent numerical tools.
Key Takeaways
- Derive and apply the spotlight SAR signal model and understand how synthetic aperture geometry maps to frequency-domain data
- Implement core image-formation algorithms including matched filtering, range compression, and azimuth focusing (backprojection and frequency-domain methods)
- Design and apply motion-compensation and autofocus techniques to correct platform-induced phase errors for high-quality images
- Analyze resolution, ambiguity, and system tradeoffs using spectral analysis and FFT-based methods
- Adapt SAR processing chains to produce derivative products such as interferometric terrain elevation maps (InSAR) and improved geolocation
- Evaluate computational and implementation considerations for real-time or batch SAR processors (sampling, windowing, aliasing, and filter design)
Topics Covered
- 1. Introduction to Spotlight-Mode SAR and Imaging Objectives
- 2. Radar Geometry and Spotlight Acquisition Modes
- 3. Signal Models: Phase History and Complex Baseband Representations
- 4. Range Processing: Pulse Compression and Matched Filtering
- 5. Azimuth Processing: Doppler, Beamforming, and Focusing
- 6. Image-Formation Algorithms: Backprojection, Polar Formatting, and Range–Doppler
- 7. Motion Compensation and Autofocus Techniques
- 8. Resolution, Ambiguity, and System Tradeoffs
- 9. Interferometry and Elevation Mapping (InSAR) Basics
- 10. Practical Implementation Issues: Sampling, Windowing, and FFTs
- 11. Performance Analysis, Calibration, and Image Quality Metrics
- 12. Applications, Case Studies, and Future Directions
Languages, Platforms & Tools
How It Compares
Compared with Curlander & McDonough's broad SAR systems reference, Wahl narrows focus to signal-processing for spotlight mode with more implementation detail; Soumekh's work is more mathematically intensive on reconstruction theory while Wahl emphasizes practical processing pipelines.
