Backprojection Autofocus of Large Ships with Arbitrary Motion for Synthetic Aperture Radar

Abstract

Radar images of the open sea taken by airborne synthetic aperture radar (SAR) show typically several smeared ships. Due to their non-linear motions on a rough sea, these ships are smeared beyond recognition, such that their images are useless for classification or identification tasks. The ship imaging algorithm presented in this thesis consists of a fast image reconstruction using the fast factorized backprojection algorithm and an extended autofocus algorithm of large moving ships. This thesis analysis the factorization parameters of the fast factorized backprojection algorithm and describes how to choose them nearoptimally in order to reconstruct SAR images with minimal computational costs and without any loss of quality. Furthermore, this thesis shows how to estimate and compensate for the translation, the rotation and the deformation of a large arbitrarily moving ship in order to reconstruct a sharp image of the ship. The proposed autofocus technique generates images in which the ...

Range Resolution and Sampling Frequency Trade-Off for GPS Passive Radar

“…In a GPS-SAR system (Fig. 1), the right and left antennas receive the direct and reflected satellite signals, respectively, and the data carried by these signals are used to image the reflection area [25].…”