Patent ID: 7145496
Filing Date: 2006-12-05
Classification: G01S

Abstract:
1. A radar on a moving platform for generating a focused synthetic aperture image of a scene from a sequence of periodic pulse returns from said scene, said pulse returns approximately motion compensated for the motion of said moving platform with respect to said scene, said radar comprising: analog to digital converter for converting said pulse returns into a digital stream; a computer for: receiving said digital stream; approximately phase aligning said pulse returns from said scene with respect to the motion of said moving platform to generate an initial synthetic aperture image, said initial synthetic aperture image formed from a plurality of pixel intensities z selecting targets from said initial synthetic aperture image using a sliding window, computing a first entropy for said targets, and sorting said targets using said first entropy to obtain a target list having target elements; concatenating said target elements to form a data matrix compatible in a dimension with a Fast Fourier Transform; iteratively computing a phase correction to be applied to said initial synthetic aperture image using an inner loop, a mid loop and an outer loop, said phase correction expressed using an orthogonal polynomial having a plurality n consecutive terms a said outer loop, using an L index, calculating an outer loop E said mid loop, using said n as an index, calculating a mid loop entropy E said inner loop, using said n as an index, calculating an inner loop entropy E applying said phase correction to said initial synthetic aperture image to obtain a focused synthetic aperture image.