Patent ID: 6466156
Filing Date: 2002-10-15
Classification: G01S

Abstract:
A method of detecting an object that changes with time within a ground area using a SAR radar, supported by a platform in essentially rectilinear motion during a synthetic aperture, comprising the steps of:transmitting radar pulses with a fractional bandwidth which is greater than or equal to 0.1 and using in calculations an aperture angle which is greater than or equal to 0.1 radians, said fractional bandwidth being a ratio between bandwidth and center frequency; registering reflected radar pulses with amplitude and phase; for each pulse, measuring, or calculating, and storing a position of the antenna which transmits the pulse and of the antenna which receives the pulse; generating a two-dimensional SAR image with cylinder geometry from each synthetic aperture; reproducing the ground area on a ground surface at least twice in succession from synthetic apertures while moving along straight paths; starting from the two-dimensional SAR images, matching at least two of the SAR images with each other by a method in which each ground area in one image is associated with the same ground area in the other image and, knowing the position and location data of the transmitting and receiving antennae and that the cylinder geometry of the SAR images is projected onto the ground surface, filtering the images so that only spectral components of ground reflectivity common to the at least two SAR images are extracted and used in the matching.