Tutorial: SAR Signal and Image Processing for ISR Applications

Presented by:
Uttam Majumder,
AFRL Sensors Directorate, USA
Mehrdad Soumekh,
Soumekh Consulting, USA

Course Description:

In this tutorial, we discuss Synthetic Aperture Radar (SAR) signal and image processing methods for Intelligence, Surveillance, and Reconnaissance (ISR) applications.  Topics that are covered include Video SAR processing, coherent and non-coherent change detection, adaptive filtering for ground moving target indication (GMTI) processing, and real-time exploitation and visualization. Particular emphasis of this presentation will be on the exploitation of SAR data that are acquired over nonlinear flight paths. Most operational SAR platforms utilize a linearflight path to interrogate an imaging scene. Such data acquisition provides limited Doppler and aspect angle information for target classification and perhaps identification and moving target detection and tracking.  A nonlinear SAR or Circular SAR data acquisition with multiple channels and polarizations enables the user to observetargets at various aspect angles, process the data for clutter cancellation, and generate 3D information of the scene.  A nonlinear SAR collection also increases the probability of detecting a weak target such as a human being (a dismount).  A practical SAR-ISR system will be analyzed, and measured data will be used to illustrate the merits of the above-mentioned algorithms.

Lecture Overview:

1. Advantage of nonlinear  multi-channel, multi-polarization SAR data
Nonlinear SAR collection enhances angular variability to observe a scatterer from multiple look angles.  Adding multi-channel and multi-polarization to the nonlinear collection enable various exploitation algorithms development such as 3D scene generation and detecting low-RCS targets

2. Video SAR processing
Real-time video SAR generation from AFRL public released Gotcha data will be illustrated.  Advantage of Backprojection and wavefront reconstruction algorithms will be discussed. A two stage backprojection algorithm that reduces the computational complexity of  n3 backprojection into a n2.5  (by applying digital spotlighting algorithm) will be presented.  Real-time SAR exploitation hardware such as GPU (Tesla) and SGI systems will be discussed

3. Coherent and non-coherent change detection Coherent and non-coherent change detection processing of SAR data will be presented. Spatial and spectral registration of multipass SAR data. Adaptive calibration of multipass SAR imagery.

4. Multiple moving target detection and tracking Adaptive filtering for SAR-GMTI processing will be presented. Single receiver non-coherent GMTI versus dual along-track receiver coherent GMTI. Multi-target detection and tracking from GMTI map.

5. Multi-touch screen interface for SAR data visualization A multi-touch screen (similar to ipod touch) based SAR visualization will be presented.

6. Conclusion

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