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In this paper, a robust CFAR detector, composed of an automatic dual censoring algorithm and the cell averaging CFAR detector, is proposed for non-homogenous environment. The new detector is named an automatic dual censoring cell averaging (ADCCA). The proposed detector does not require any prior knowledge about the background environment and uses two threshold values to reject the unwanted samples...
The paper proposes a novel constant false alarm rate (CFAR) detector using Markov chain models, an innovative new technique that will utilize the finer resolution of RADARSAT-2 to yield improved detection performance for higher-resolution objects. The Markov chain based CFAR detector extends traditional PDF based CFAR detection to first-order Markov chain model by considering both correlation between...
The joint suppression of returns from land and weather clutter is required in many radar applications. Although the optimal method of land-weather clutter suppression is known, the solution is usually not practical to implement. In this paper, we propose a method that employs rank-1 and rank-2 approximations on the weather clutter correlation matrix to obtain suboptimal but simpler detectors which...
For composite hypothesis testing, the generalized likelihood ratio test (GLRT) and the Bayesian approach are two widely used methods. This paper investigates the two methods for signal detection of a known waveform and unknown amplitude with distributed sensors. It is first proved that the performance of the GLRT can be poor. Secondly, a direct way of improving the GLRT is proposed. Thirdly, an approximate...
This paper demonstrates the usefulness of an ultra wideband target recognition method in the case of realistic and complicated target geometries at resonance region. The method utilizes the MUSIC algorithm to extract the natural resonance-related scattering features of targets. The resulting features give the power distribution maps of targets. These maps are called as fused MUSIC spectrum matrices...
A stylized compressed sensing radar is proposed in which the time-frequency plane is discretized into an N by N grid. Assuming that the number of targets K is small (i.e. KLtN2), then we can transmit a sufficiently ldquoincoherentrdquo pulse and employ the techniques of compressed sensing to reconstruct the target scene. A theoretical upper bound on the sparsity K is presented. Numerical simulations...
The passive radar has been revitalized through the passive coherent location technology. These systems have unique properties, especially is time on target high compared to traditional radar systems, as well as the freedom in choosing from the available transmitters of opportunity. This paper will focus on how to take advantage of the latter of these two special properties in order to achieve better...
The paper presents a method for estimation of acceleration in passive coherent location (PCL) radar. The method is based on the Generalized Chirp Transform, which is a maximum likelihood estimator in this case. The authors propose a fast and efficient algorithm for calculating acceleration by filtering a two-dimensional range-Doppler surface. The algorithm is tested on simulated data as well as on...
This paper deals with the problem of analyzing the RADAR scattering from small constructive details on low RCS platforms. Starting from the ILDC formulations of gaps and cracks, as proposed by Shore-Yaghjian and other authors, we have generalized its applicability exploiting numerical results arising from 2D simulations. The procedure is simple and straightforward and allows the analysis of shapes...
Inverse synthetic aperture radar (ISAR) has been highly exploited for target recognition due to its high resolution imaging capability. Scaling of the ISAR image is a necessary step to the reliable target recognition. Usually, the target motion is unknown. The amount of rotation during the observation cannot be determined, so it is difficult to perform the cross-range scaling. In this paper, a technique...
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...
Both the generalization to space-time adaptive processing (STAP) and to an arbitrary number of targets, of a multiple beamforming technique and its adaptation to noise-like signals are presented in this paper. A hybridization of both the joint domain localized (JDL) and the direct data domain (D3) STAP methods is used to prove the feasibility of multi-target detection in the presence of either homogeneous...
In this paper, a new spectral estimation method, which is based on the rank-deficient sample covariance matrix, is proposed. The new method applies the amplitude and phase estimation (APES) filter and the Capon weight simultaneously on the data matrix to obtain the complex amplitude estimate of the spectral line of interest. Because the sample covariance matrix is singular, a rank-deficient version...
The use of adaptive techniques may prove useful in the processing of radar signals. The proposed radar clutter classificator is aimed to improve the detection of snow clutter presence in data acquired by a ground radar system in an air traffic control environment. The classifier receives as input a set of features which describe the appearance of the same plot in two consecutive scans of the ground...
Planar antenna arrays are widely used as transmitting and receiving part of monopulse trackers because of the need to generate sum and difference radiation modes to estimate the angular location of an unknown target. In such a framework, this paper presents an innovative synthesis technique able to synthesize two orthogonal sub-arrayed difference patterns close to an optimal reference one. The proposed...
In this paper we introduce a new switched order statistics CFAR test (SW-OS) for detecting a radar target in the presence of nonhomogeneous clutter and/or multiple interfering targets situation. Whereas a switching CFAR test (S-CFAR) was recently proposed in the literature for addressing a similar background scenario, unlike the S-CFAR test, the test proposed here does not utilize the test cell statistic...
In this paper, we propose and assess an adaptive radar detector that can adjust its ldquodirectivityrdquo through a real scalar parameter. Proper choices of such a parameter return, as special cases, the well-known Kellypsilas GLRT and the recently introduced W-ABORT detector. More important, through the tuning of the above parameter one can control the level to which sidelobe signals are rejected...
To check the capabilities of a dasiashared aperturepsila, at FGAN the PALES experimental system is built up. Especially array signal processing with a multibeam system is investigated. In this paper the basics of signal detection by square law detectors are discussed. The proposed signal detection method is based on a time frequency representation. Besides signal detection also the PRF of the received...
This paper formulates and solves the sensor placement problem for efficient target localization in a sensor network. We illustrate our approach through a missile defense problem where the objective is the efficient localization of the missile using multiple sensors. We develop a mathematical framework for the localization of the missile using multiple sensors based on Cramer-Rao lower bound (CRLB)...
This paper deals with covariance matrix estimation for radar detection in non-Gaussian noise modeled by spherically invariant random vector (SIRV). In many applications, it is possible to assume a particular structure for the clutter covariance matrix: this is the case for instance for active systems using a symmetrically spaced linear array or pulse train. In this paper, we propose to use the particular...
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