Sharpening bistatically acquired imagery

This paper considers imaging of stationary active RF emitters, such as ground based radars, using a passive bistatic system in which one or both of the sensor platforms is/are moving. A popular ldquosimplerdquo approach to generating ldquolocation-truerdquo imagery from such a system is based on computing the ldquoambiguity surfacerdquo [R. Tolimieri and S. Winograd, 1985], [L. Auslander and R. Tolimieri, 1988], [C.L. Yatrakis, 2005]. This approach, which involves a basic 2-D DFT step, however ignores the ldquoblurringrdquo effect due to time variations induced by the relative platform movement. This paper develops a computationally efficient modification to this 2-D DFT process, which employs a commonly accurate parametric model of the time variations and exploits a unique relationship within the co-ordinate system of the ambiguity surface image. The result is ldquohighlyrdquo sharpened location-true imagery. The paper also briefly discusses extending the proposed procedure to imaging of passive objects with an active RF bistatic system.