Algorithms for Refocusing Moving Ships in RADARSAT-2 Spotlight Imagery – A study based on 11 Gibraltar scenes


  1. Dragosevic, M.
Corporate Authors
Defence Research and Development Canada, Ottawa Research Centre, Ottawa ON (CAN);MDA, Ottawa Ont (CAN)
This report describes the work done under the contract W7714-091140/001/SV R&D Support for SAR-Based Geospatial Intelligence and Terrain Analysis. The specific task addressed in this report is to study the algorithms for ship refocusing in high resolution RADARSAT-2 Synthetic Aperture Radar (SAR) scenes. Recent publications on this topic, as well as the Defence Research and Development Canada (DRDC) legacy code, have been examined. Two approaches have been selected, tested and further refined. One approach is based on adaptive tracking in the range-Doppler domain, which is an alternative to the time-frequency distribution. This method filters out the target signature by adaptively tuning the filter to the residual variations in the target Doppler rate. Then the tuning history is used for motion compensation. The other approach is based on the multi-looking concept. Different Doppler looks are first transformed into detected pixel clusters and then their misregistration is measured in the spatial domain. The look misregistrations are converted into the phase function for motion compensation. Both methods are tested on 11 Spotlight-A (SLA) Gibraltar scenes acquired in January and February of 2017. The original Single Look Complex (SLC) imagery and the refocused imagery is shown for small data tiles around detected ships. There is a significant improvement in many cases.
Report Number
DRDC-RDDC-2018-C010 — Contract Report
Date of publication
01 Jan 2018
Number of Pages
Electronic Document(PDF)

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