Time-varying step-transform algorithm for high squint SAR imaging

Citation
Xb. Sun et al., Time-varying step-transform algorithm for high squint SAR imaging, IEEE GEOSCI, 37(6), 1999, pp. 2668-2677
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
ISSN journal
0196-2892 → ACNP
Volume
37
Issue
6
Year of publication
1999
Pages
2668 - 2677
Database
ISI
SICI code
0196-2892(199911)37:6<2668:TSAFHS>2.0.ZU;2-V
Abstract
High-squint angle synthetic aperture radar (SAR) imaging has applications i n specific situations such as providing looking angle-dependent scattering information and revisiting an area of interest. It is very difficult for cu rrent SAR-imaging algorithms to be used directly in high-squint configurati ons. This is due to the large range-cell migration and the nonnegligible cu bic-phase term in the signal. In this paper, an improved algorithm called t he time-varying step-transform algorithm is proposed. It uses different chi rp rates to deramp the signal in different subapertures to alleviate the ra nge-focus problem. The interval between subapertures is also varied accordi ng to the deramping chirp rate. The nonnegligible cubic-phase term is inclu ded in the focusing procedure. The performance of the proposed algorithm in high-squint-angle mode is excellent, By reducing the subaperture length as the squint angle is increased, the performance of the algorithm is almost independent of squint angle. The proposed algorithm is also flexible for mu ltilook processing and motion-error compensation.