1,721,093 research outputs found
Polarimetric inverse synthetic aperture radar
No full textPol-ISAR has proven to be more accurate and more effective than single-channel ISAR when used for target recognition. Given the limited amount of such systems and available data and literature, this is a field that can still benefit from additional study and experimentation to fully exploit its potential. The use of polarimetry involves additional receiving channels in the radar system and therefore it increases the complexity of cost of the overall radar system. This creates a trade-off that must be considered when designing ISAR systems for target recognition. Nevertheless, when size, weight, power and cost constraints are favourable, the benefit of using full polarization is significant both in terms of image quality, by producing better focused images, and in terms of the amount of information (features) that can be exploited to improve target classification performances
Radar Imaging for maritime observation
No full textRadar imaging is one of the most important tools for monitoring the sea surface. This book presents the most recent radar signal processing techniques and innovative radar concepts. The first part of the book discusses mathematical details of both SAR and ISAR techniques. The second part focuses on real applications and the results obtained by processing real data. Some applications discussed are oil spill detection through fractal analysis, non cooperative maritime object imagery, and detection of ships responsible for oil slicks
Theoretical foundation of passive bistatic ISAR imaging
No full textPassive bistatic inverse synthetic aperture radar (PB-ISAR) has been recently introduced to add an important capability to passive coherent location (PCL) systems. Although evidence of such capability has been provided, a theoretical background that supports such findings is needed to fully comprehend PB-ISAR imaging. This paper provides a full theoretical basis for PB-ISAR including a performance analysis in terms of spatial resolution. Examples with real data are also provided as case studies
Range Doppler and Image Autofocusing for FMCW Inverse Synthetic Aperture Radar
No full textInverse synthetic aperture radar (ISAR) is a well-known technique for obtaining high-resolution radar images. ISAR techniques have been successfully applied in the recent past in combination with pulsed coherent radar. In order to be more appealing to both civilian and military fields, imaging sensors are required to be low cost, low powered, and compact. Coherent pulsed radars do not account for these requirements as much as frequency modulated continuous wave (FMCW) radars. However, FMCW radars transmit a linear frequency modulated (LFM) sweep in a relatively long time interval when compared with the pulse length of a coherent pulse radar. During such an interval the assumption of stop&go is no longer valid, that is the target cannot be considered stationary during the acquisition of the entire sweep echo. Therefore, the target motion within the sweep must be taken into account. Such a problem is formulated and solved for ISAR systems, where the target is noncooperative and additional unknowns are added to the signal model. In the present work, the authors define a complete FMCW-ISAR received signal model, propose an ISAR image formation technique suitable for FMCW radar and derive the point spread function (PSF) of the imaging system. Finally, the proposed FMCW ISAR autofocusing algorithm is tested on simulated and real data
ISAR Imaging via Compressive Sensing
No full textThis paper aims at giving an overall view of the use of Compressive Sensing (CS) for some applications of Inverse Synthetic Aperture Radar (ISAR) imaging, especially for those where conventional Fourier based approaches typically fail. A number of case studies have been investigated in this paper and CS algorithm’s performances have been numerically evaluated via the definition of image contrast
Automatic Target Recognition on Terrestrial Vehicles based on Polarimetric ISAR Image and Model Matching
No full textAn Automatic Target Recognition (ATR) algorithm has recently been proposed that makes use of Polarimetric ISAR images and a Model Matching approach. In this paper, the authors propose a variation of such an approach that is suitable for ATR of terrestrial vehicles. The effectiveness of the proposed implementation is tested by means of real data acquired during a controlled turn-table experiment
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