<title>Refocus of constant-velocity moving targets in synthetic aperture radar imagery</title>

Abstract

APR 0 8 1998The detection and refocus of moving targets in SAR imagery is of interest in a number of applications. In this paper we address the problem of refocusing a blurred signature that has by some means been identified as a moving target. We assume that the target vehicle velocity is constant, i.e., the motion is in a straight line with constant speed. The refocus is accomplished by application of a twedimensional phase function to the phase history data obtained via Fourier transformation of an image chip that contains the blurred moving target data. By considering separately the phase effects of the range and cross-range components of the target velocity vector, we show how the appropriate phase correction term can be derived as a two-parameter function. We then show a procedure for estimating the two parameters, so that the blurred signature can be automatically refocused. The algorithm utilizes optimization of an image domain contrast metric. We present results of refocusing moving targets in real SAR imagery by this method.

Smear signature morphology of surface targets with arbitrary motion in spotlight synthetic aperture radar imagery

“…Specifically, the objectives of target motion analysis, moving target detection and moving target imaging are interrelated, as any attempt to detect moving targets in SAR via imaging will require a detailed understanding of the defocus smearing effects induced by target motion in SAR imagery. For example, Jakowatz et al [5] have investigated the properties of constant velocity targets in SAR imagery. In addition, Rigling [6] has developed a method for focusing rotating targets that are rotating via an image entropy optimisation process.…”

Ground Moving Target Imaging Using Ultranarrowband Continuous Wave Synthetic Aperture Radar

“…We adopt an approach similar to [6], [10], [15], and [17] and form a set of reflectivity images for a range of hypothesized velocities for each scatterer. Unlike the traditional SAR reflectivity imaging where the measurements are backprojected onto the constant range contours, we form reflectivity images by filtering and backprojecting the preprocessed received signal onto the constant bistatic temporal Doppler contours for a given 0196-2892 © 2013 IEEE hypothesized velocity.…”

Passive synthetic aperture radar imaging of ground moving targets

“…We present an FBP method combined with an entropy optimization to reconstruct focused images of the ground and to determine the velocity of moving targets. Similar to the approach in, 17,18 we reconstruct…”