The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This talk will provide an overview of adaptive radar signal processing starting from the early work of Howells, Applebaum and Widrow on adaptive arrays. The sample matrix inverter (SMI) method and its variants will be discussed in some detail. The focus of the discussion will be on the constant false alarm rate (CFAR) characteristics. These methods are based on the formation and inversion of a sample...
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...
Calculating accurate low-rank covariance estimates for sensor arrays with a large number of elements is a common task in signal processing. Many algorithms make use of the exact spectral decomposition of the empirical covariance structure-but the singular value decomposition is often too costly in practice, owing to array size or constraints on computation. Recent approaches geared toward the approximate...
Post-Doppler methods are rank reduction techniques to reduce temporal dimensions by applying the Doppler filter and can reduce the processing time than full degrees-of-freedom (DOF) space-time adaptive processing (STAP). In post-Doppler methods, multi-bin post-Doppler methods are generally used to improve the performance of signal-to-interference-plus-noise ratio (SINR). However, it is necessary to...
The utilization of diversity in radar systems has shown improvements over conventional beamforming phased array radars in many aspects of the system performance including target detection probability, the number of identifiable targets, and beam-pattern synthesis. When linearly independent signals are transmitted, the signals received from targets at different locations are also linearly independent...
We analyze the performance of a recently described class of two-dimensional autoregressive parametric models for space-time adaptive processing (STAP) in airborne radars on the DARPA side-looking radar model known as KASSPER Dataset 1. We investigate the trade-offs between signal-to-interference-plus-noise ratio (SINR) degradation (with respect to the optimal clairvoyant receiver) due to the mismatch...
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...
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...
In this paper, we consider the problem of knowledge-aided covariance matrix estimation and its application to adaptive radar detection. We assume that an a-priori (knowledge-based) estimate of the disturbance covariance M, derived from a physical scattering model of the terrain and/or of the environment, is available. Hence, starting from a set of secondary data, we evaluate the maximum likelihood...
In this paper the STAP detector based on the low-rank approximation of the normalized adaptive matched filter (LRNAMF) is investigated for its false alarm probability (FAP) performance. An exact formula for the FAP of the LRNAMF detector is derived using the g-method estimator [4]. The non-CFAR behavior of this detector is shown via simulations using different models for the clutter-plus-noise covariance...
Digital audio/video broadcasting (DAB/DVB-T) is already available in a large area of Europe. The advantage of using these signals for passive air surveillance is the disposability of a large range of illuminators sending an easily decodeable digital broadcast signal. In the considered multi-static scenario, one observer provides bistatic time difference of arrival (TDoA) and Doppler measurements....
This paper presents an improved estimation scheme when the clutter distribution is unknown. The Empirical Likelihood (EL) is a recent semi-parametric estimation method which allows to estimate unknown parameters by using information contained in the observed data such as constraints on the parameter of interest as well as an a priori structure. The aim of this paper is twofold. First, the empirical...
Adaptive signal detection for scenarios with a limited number of sources of interest and background interferers (less than the number of antenna elements) can be efficiently executed using diagonally loaded covariance matrix estimates, but the resultant detectors are not strictly constant false-alarm rate (CFAR). The loss of ldquoCFARnessrdquo means that the problem of adaptive interference mitigation...
Recently, the knowledge-based clutter covariance estimate methods are developed to improve the convergence rate. In this paper, the relationship between some widely-used knowledge-based methods and the traditional reduced-order methods are established. It is found that the colored loading (CL) is equivalent to the pre-whitened diagonal loading (DL), and the fast maximum likelihood with assumed clutter...
Detection of moving targets in stationary clutter can be accomplished by STAP radar. In contrast to monostatic radar the performance of bistatic STAP depends strongly on the actual radar-target geometry. Even for sidelooking radar the clutter Doppler is generally range dependent which causes special problems in estimating the space-time clutter covariance matrix. For certain bistatic constellations...
We consider space-time adaptive processing (STAP) when the radar returns are recorded by a conformal antenna array (CAA). The statistics of the secondary data snapshots used to estimate the optimum weight vector are not identically distributed with respect to range, thus preventing the customary STAP processor from achieving its optimum performance. The compensation of the range dependence of the...
A multi-input multi-output (MIMO) radar system, unlike a standard phased-array radar, can transmit multiple probing signals that are correlated or uncorrelated with each other. This waveform diversity offered by the MIMO radar is the main reason for its superiority over the standard phased-array radar. An interesting current research topic in MIMO radar is the optimal synthesis of the transmitted...
In this paper we deal with the problem of adaptive detection of mismatched mainlobe targets and/or sidelobe interfering signals that are distributed in range. More precisely, in order to improve the robustness of the decision rule in presence of mainlobe targets we investigate the impact of modeling the actual useful signal as a vector belonging to a proper cone with axis the nominal steering vector;...
Knowledge about the lateral target length may be useful in several applications such as convoy tracking and alerting a high resolution imaging mode for classification. We focus on the estimation of the apparent length of an extended target with particular emphasis on convoys of ground vehicles. The estimation is done by applying generalised power estimators to the output signals of an array antenna...
This paper present a STAP algorithm for an airborne high PRF pulse Doppler sensor based on clutter segmentation process that allows the inversion of a LN x LN matrix instead of MN x MN estimated on a single CPI (coherent processing interval). Since the radar works with the spectra of the received signals itpsilas possible to obtain the estimation of the covariance matrix simply eliminating from the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.