Simulation of the Effects of Hard Limiting on Image Quality of Synthetic Aperature Radar

Abstract

Starting with a magnetic tape of a scene viewed by the ERTS (Landsat) satellite, we simulated the radar return of reflectors whose average intensity matched that of the picture elements in the scene. The returns were processed in three ways: normally or with no quantization, with a procedure simulating IF (intermediate frequency) hard limiting, and with a procedure simulating video (baseband) hard limiting. For each type of processing we developed an image for a one, two, and four-look system. We found that IF limiting is slightly better than video limiting, while both can be reasonable trade-offs of image quality for reduced data rates when the number of looks is four or less. These conclusions are supported by photographs representing the different processing techniques.