Fusion of ladar and SAR for terminal guidance

Abstract

A concept for integrating the airborne sensing capabilities of synthetic aperture radar (SAR) with laser detection and ranging (LADAR) for terminal guidance is presented. The advantages of each technology in the reconnaissance and terminal guidance roles for target acquisition are exploited. The concept is directed at terminal guidance against fixed and quasi-fixed targets (i.e., targets expected to be in approximately the same location and orientation from the time of reconnaissance to the time of targeting). The advantages of airborne SAR are high resolution, all-weather, standoff reconnaissance capabilities. The advantages of LADAR are high resolution in the real aperture mode using moderately sized and priced optics, and good performance over modest ranges (on the order of a kilometer or less). Within the concept, LADAR would provide terminal guidance using two SAR provided data sets: (1) target estimated coordinates, and (2) the SAR imagery of target/surround. Technical risks are: lack of a demonstrated capability for SAR-to-LADAR image correlation; lack of analysis of low- cost, light weight LADAR and real-time correlators; and lack of analysis of adequate signal- to-noise in a range of atmospheric environments. This paper is directed at the use of SAR image by the LADAR for aim point refinement. It addresses geometric differences in the SAR and LADAR images, the effect of different reflectances on scene segmentation, and the basis for an approach for developing common geometric projections for the SAR and LADAR image correlations.