Focusing ISAR Images using the AJTF Optimized with the GA and PSO Algorithm - Comparison and Results

Abstract

Algorithms based on the genetic algorithm (GA) and the particle swarm optimization (PSO) algorithm were designed for focusing inverse synthetic aperture radar (ISAR) images that suffered from degradation due to Doppler smearing. These algorithms optimized the adaptive joint-time frequency (AJTF) algorithm by replacing the exhaustive search as the primary search tool used to determine focusing parameters. The use of the PSO for ISAR image focusing is a unique application of this evolutionary search. Performance of the GA and the PSO were compared with the PSO producing the optimal results of being able to focus a 2/sup 11/ pulse ISAR image in 9 seconds or 24% of the cost function calculations required for an exhaustive search. This paper also introduces a new method of determining basis function suitability using the fast Fourier transform.