Synthetic Aperture Radar Imaging with Motion Estimation and Autofocus
نویسندگان
چکیده
We introduce from first principles a synthetic aperture radar (SAR) imaging and target motion estimation method that is combined with compensation for radar platform trajectory perturbations. The main steps of the method are (a) segmentation of the data into properly calibrated small apertures, (b) preliminary motion estimation from the data using the Wigner transform and the ambiguity function, (c) compensation for platform trajectory perturbations using the Wigner transform and the ambiguity function of small aperture preliminary images, and (d) construction of high resolution images over wide apertures using the estimated motion and platform trajectory perturbations. The analysis provides quantitative criteria for implementing the aperture segmentation and the parameter estimation process. X-band persistent surveillance SAR is a specific application that is covered by our analysis. Detailed numerical simulations illustrate the robust applicability of the theory and validate the theoretical resolution analysis.
منابع مشابه
A weighted eigenvector autofocus method for sparse-aperture ISAR imaging
With the development of multi-functional radar systems, inverse synthetic aperture radar (ISAR) imaging with sparse-aperture (SA) data has drawn considerable attention in the recent years. Motion compensation and imaging are among the most significant challenges that SA-ISAR imaging frequently faces. In this paper, we focus on the autofocus scheme, in which a modified eigenvector-based autofocu...
متن کاملSAR Imaging of Moving Target based on Knowledge-aided Two-dimensional Autofocus
Due to uncertainty on target's motion, the range cell migration (RCM) and azimuth phase error (APE) of moving targets can't be completely compensated in synthetic aperture radar (SAR) processing. Therefore, moving targets often appear two-dimensional (2-D) defocused in SAR images. In this paper, a 2-D autofocus method for refocusing defocused moving targets in SAR images is presented. The new m...
متن کاملA fast autofocus algorithm for synthetic aperture radar processing
Synthetic Aperture Radar ( S A R ) has become a valuable instrument with applications in reconnaissance and remote sensing. High resolution SAR imaging requires the motion of the radar platform to be known very accurately. Otherwise phase errors are induced in the processing of the raw S A R data, and bad focusing results. In particular, a constant error in the measured along track velocity or ...
متن کاملBackprojection Autofocus for Synthetic Aperture Radar
In synthetic aperture radar (SAR), many adverse conditions may cause errors in the raw phase-history data. Autofocus methods are commonly used in SAR to mitigate the effects of these problems. Over the years, many types of autofocus have algorithms have been created, however, each has implicit assumptions restricting their use. The backprojection image formation algorithm places few restriction...
متن کاملInterferometric height estimation of the seafloor via synthetic aperture sonar in the presence of mo - Radar, Sonar and Navigation, IEE Proceedings -
An end-to-end simulated processing chain related to an existing synthetic aperture sonar (SAS) system is developed and described, including motion compensation, efficient image formation and autofocus procedures. The processing is extended to include interferometric height estimation capability. It is the goal of the paper to study the application of interferometry to SAS systems in the presenc...
متن کامل