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The modeling of the clutter echoes is a central issue for the design and performance evaluation of radar systems. The aim of this paper is to describe the state-of-the-art approaches to the modeling and understanding of land and sea clutter echoes and their implications on performance prediction and signal processors design. The tutorial is mainly divided in 5 parts: (i) Radar sea and ground clutter...
Since its inception 30 years ago perhaps no innovation in radar technology has made such a tremendous impact on the field as that of radar interferometry. Radar interferometry uses two or more observations separated in either time or space to measure fraction of a wavelength scale range differences between the two observations. Radar interferometry is used by scientific, commercial and government...
This tutorial presents a state-of-the-art survey of advanced applications of Synthetic Aperture Radar (SAR). Applications include: the detection and recognition of targets in SAR imagery, and the detection of targets under trees (and in the open) using change detection (coherent change detection, full-polarization change detection, etc). A fully polarimetric SAR sensor is described. Models of clutter...
The objective of this work is to develop optimal polarimetric Constant False Alarm Rate (CFAR) ship detection system. Polarimetric transformation/decompositions, clutter analysis, modeling, Principal Component Analysis (PCA), and multi-CFAR detection are the necessary components of optimal polarimetric CFAR ship detectors. The resulting CFAR detector outperforms the conventional polarimetric CFAR...
Circular shifting and windowing have been introduced to improve the performance of Doppler centroid tracking (DCT) in inverse synthetic aperture radar (ISAR) image focusing when the target has prominent scattering centers. However, the conventional unified windowing method is hard to implement and affects the performance of DCT. An adaptive windowing method based on ISAR target extraction is proposed...
A new efficient method to obtain high resolution ISAR images in the case of missing observation data is presented. The available data segments are modeled by 2-D linear prediction of 2-D Cartesian frequency spectra using 2-D orthogonal lattice filters. Then the prediction models are used to estimate the missing data segments. It is shown that the IFT processing of the resulting data achieves better...
Helicopters are essential for any mission of humanitarian or assisting nature in disaster areas. Very often they have to cope with missing infrastructure and extreme environmental conditions. Besides darkness and adverse weather, dust and snow are two of the most dangerous conditions for helicopter landing. At the time being, helicopter pilots have no adequate sensors to get information on height...
Through-the-wall radar imaging attempts to image complex scenes within enclosed structures. While most of the high-resolution imaging techniques assume point targets, indoor imaging requires dealing with single or multiple walls which are extended targets in nature and violate the point-target assumption. In order to provide high quality imaging, we need to consider point targets and extended targets...
The Cassini Titan Radar Mapper is one of the twelve instruments on board the Cassini spacecraft. The main goal of the radar is to map the surface of the larger of the Saturnian satellite, Titan, not excluding observation of the other icy satellites. The Cassini RADARr is a multimode instrument capable of providing not only images, when used in the SAR mode, but also the topography of the surface when...
This paper proposes a new parameter based method of SAR image feature extraction and complex image information retrieval. The methodpsilas groundwork is the Fast Fourier Transform, each of the proposed parameters being built on a Fourier Transform basis. We suggest that by the use of several image bands formed of distinct spectral signatures of the original complex image, one can obtain a valid spectral...
One of the most important issue in maritime international transport is the necessity of increasing the level of safe in vesselpsilas navigation. We can achieve this goal using various methods. One of them is the enlargement and enrichment of navigational data processed by own deck computer net and external systems AIS (Automatic Identification System) and VTS (Vessel Traffic Service). The radar image...
Automatic target recognition (ATR) is an important capability for defense application. ATR removes the human operator from the process of target acquisition and classification, reducing the reaction time to possible threats and can be used to gun target engagement. This paper presents one technique used to solve the automatic target recognition problem in synthetic aperture radars (SAR) images, that...
An experimental radar operating simultaneously at 10 GHz, 35 GHz, 94 GHz and 220 GHz has been developed, which is capable to deliver an instantaneous bandwidth of 4000 MHz at the lower frequency bands and 8000 MHz at 220 GHz. The radar is of FM-CW type and uses a chirp modulation. Two types of application have been envisaged, both to determine the scattering centre distributions of targets, one using...
This paper extends the concept of autofocus in SAR processing procedure and proposes an adaptive algorithm for SAR data focusing. The novel algorithm discards the hypothesis in the autofocus algorithms, i.e. the range migration has been removed perfectly, and moves the ldquoadaptiverdquo processing to the front of RCMC. By adjusting the parameters for focusing adaptively, the range migration in the...
Synthetic aperture radar raw data simulation serves many purposes such as testing different image formation algorithms, studying the interaction of electromagnetic waves with a scene being imaged, testing and validating different system design parameters, etc. Frequency domain raw data simulation can be used to generate the raw data efficiently, as compared to time domain simulation. However, contrary...
The availability of long sequences of SAR data virtually at any location on the Earth allows an extensive evaluation of land cover dynamics, which is a well-known extension to image pair multitemporal analysis. In this work we show the first results of an extensive evaluation of one among these ldquohypertemporalrdquo SAR sequences, with a stress on urban area monitoring.
Speckle reduction is a prerequisite for many synthetic aperture radar (SAR) image processing tasks. In recent years, the hidden Markov tree (HMT) in wavelet domain is widely used for speckle reduction. The HMT model captures the persistence property of wavelet coefficients, but lacks the clustering property of them within a scale, whereas the Gaussian Markov random field (GMRF) model can characterize...
In radar imaging, it's well known that relative motion or deformation of parts of illuminated objects induce additional features in the Doppler frequency spectra. These features are called micro-Doppler effect and appear as sidebands around the central Doppler frequency. They can provide valuable information about the structure of the moving parts and may be used for identification purposes. Previous...
Synthetic aperture radar (SAR) is active and coherent microwave high resolution imaging system, which has the capability to image in all weather and day-night conditions. SAR transmits chirp signals and the received echoes are sampled into In-phase (I) and Quadrature (Q) components, generally referred to as raw SAR data. Raw data compression is an essential future requirement for high resolution space...
In this paper, the residue is extended to the second order, which is called second order residue. Second order residue is researched and applied in the interferometric synthetic aperture radar (SAR) phase unwrapping. Similar to the residue, the second order residue reflects the discontinuity in the wrapped phase. In phase unwrapping, the traditional residue is normally used to form the branch cut...
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