Use of Radarsat to search for downed aircraft

A US Air Force A-10 aircraft was reported missing on April 10, 1997. A large search effort was undertaken to locate the pilot, plane, and on-board ammunition. Images from Radarsat, a commercial remote sensing synthetic aperture radar system, were utilized to support the search efforts. This paper describes the exploitation chain which proved instrumental in providing the information that narrowed the search for the wreckage of the A-10. The processing described in this paper is focused on a newly developed automatic detection filter and the utility of this sieve filter on various Radarsat image modes. The mathematical description of the sieve filter is given. The description of the filter includes the parameters which were tuned for the detection of objects the size of the A-10. Processing results are supplied from various studies employing the sieve filter. The results are presented as receiver-operator characteristic curves which plot the probability of detection versus the probability of false alarm. A discussion is included of the various processing modes of Radarsat imagery which were acquired and exploited in support of the A-10 search. The effectiveness of the sieve filter against the various Radarsat image collection and processing modes is presented. This study includes the actual Colorado mountain crash site of the A-10.