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Operational Interferometric SAR Data Processing for RADARSAT Using a Distributed Computing Environment

TAYLOR, Stephen C. (staylor@atlsci.com), ARMOUR, Bernard, HUGHES, William H., KULT, Andrew, NIZMAN, Chris, Atlantis Scientific, Inc., 20 Colonnade Road, Suite 110, Nepean, Ontario, K2E 7M6, Canada

Key Words: distributed computing, SAR interferometry

There has recently been a surge of interest in interferometric value-added products for SAR data by RADARSAT and other spaceborne SAR sensors. These products primarily include digital elevation models (DEMs) and deformation maps. The high level of demand has put a strain on traditional interferometric SAR (InSAR) processing tools, which have been designed for research purposes. We present a production, or operational, approach to InSAR processing that emphasizes maximal throughput and algorithmic robustness, as well as around-the-clock operation requiring relatively little/unskilled supervision. The basis for this approach is an application environment known as A Performance Emphasized Production Environment for Remote Sensing, or peppers TM.

PeppersTM uses a distributed parallel computing tile-based pipelined approach to processing remotely sensed image data products, which are characterized by their very large size (often more than 500MB). It makes use of the inherently localized nature of most image processing algorithms to formulate the division labour both spatially across the image and temporally along the pipeline of transformations. This formulation can be used to split the load among all available processing units, either using multiple threads of execution on a multi-CPU computer, or using a message passing technique (MPT) to coordinate multiple processes distributed across a networked cluster of computers.

PeppersTM represents an end-to-end approach to operational processing of remote sensing data. It's components manage every aspect of the production run, including such things as automatic update of intermediate products following a change, auditing of historical results, and the ability to trap exceptional conditions and redirect the approach to overcome these conditions. It is anticipated that peppersTM will form the basis for future operational remote sensing applications.

The development of peppersTM is supported in part by the RADARSAT User Development Program of the Canadian Space Agency.