<title>Time-integrating compact hybrid optical processor for SAR image formation</title>

Abstract

The development and airborne demonstration of a compact realtime optical processor for synthetic aperture radar (SAR) image formation under the DARPA TOPS program is described. The ERIM spotlight mode SAR system and its processing requirements are presented. It is shown that a 2-D Fourier transforming time-integrating interferometrically based optical processor is an attractive solution to the processing requirements. The optical processor uses a modulated laser diode for radar signal insertion, crossed acousto-opto scanners for 2-D scanning, a modified Köster interferometer for fringe generation, fast detector arrays for light detection and integration, and accumulating frame grabbers to build up the dynamic range of the image. Analysis, simulation, and laboratory experimental results are presented. 0-81 94-0869-7/92/$4.00

<title>Optical processor for SAR image formation: performance trades</title>

“…Thus, we can formally write that the complex image S(F) is given by (1) where s(f) is the PH signal after motion compensation and weighting has been applied, and f is the PH (spatial) frequency coordinate given by __ (2) where u is the instantaneous radar frequency, R0 is the instantaneous unit vector line-of-sight from the so called motion compensation point (MCP) to the radar, and c the speed of light constant. The detected image is S(i) I2• Thus, as implied by Eq.…”