A key assumption in monopulse based angle-of-arrival (AOA) estimators is that at most one return from a single object is present in each range cell, or equivalently in each sample of the matched filter output. These a...
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ISBN:
(纸本)0819450774
A key assumption in monopulse based angle-of-arrival (AOA) estimators is that at most one return from a single object is present in each range cell, or equivalently in each sample of the matched filter output. These algorithms break down if the data consists of merged measurements-multiple target returns contained in the same range cell. The proposed technique makes use of data from a three channel monopulse radar to estimate the AOA of two targets from merged measurements. Specifically, the technique capitalizes on the structure of squint beams in conjunction with multiple range samples to resolve the multiple targets. The paper focuses on the development of the new algorithm along with results from computer simulations that demonstrate its viability. To illustrate the utility of this technique to target tracking problems, comparative Monte Carlo results of performance of a tracker with the new technique and conventional monopulse AOA estimates are provided.
Radar systems are an important component in military operations. In response to increasingly severe threats from military targets with reduced radar cross sections (RCSs), slow-moving and low-flying aircraft hidden in...
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Radar systems are an important component in military operations. In response to increasingly severe threats from military targets with reduced radar cross sections (RCSs), slow-moving and low-flying aircraft hidden in foliage, and in environments with large numbers of targets, knowledge-based (KB) signal and dataprocessing techniques offer the promise of significantly improved performance of all radar systems. Radars under KB control can be deployed to utilize valuable resources such as airspace or runways more effectively and to aid human operators in carrying out their missions. As battlefield scenarios become more complex with increasing numbers of sensors and weapon systems, the challenge will be to use already available information effectively to enhance radar performance, including positioning, waveform selection, and modes of operation. KB processing fills this need and helps meet the challenge.
Because vehicles moving over ground generate a succession of impacts, the soil disturbances propagate away from the source as seismic waves. Thus, in the battlefield environment, we can detect moving ground vehicles b...
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Because vehicles moving over ground generate a succession of impacts, the soil disturbances propagate away from the source as seismic waves. Thus, in the battlefield environment, we can detect moving ground vehicles by means of measuring seismic signals using a seismic velocity transducer, and automatically classify and recognize them by advance signalprocessing method. Because seismic sensor is easy to be developed by emerging micro-electro-mechanical system (MEMS) technology, seismic detection that will be low cost, low power, small volume and light weight is a promising method for moving ground targets. Such a detection method can be used in many different fields, such as battlefield surveillance. traffic monitoring, law enforcement and so on. The paper researches seismic signals of typical vehicle targets in order to extract features of seismic signal and to recognize targets. As a data fusion method, the technique of artificial neural networks (ANN) is applied to recognize seismic signals for vehicle targets. An improved BP algorithm and ANN data fusion architecture have been presented to improve learning speed and avoid local minimum points in error curve. The algorithm had been used for classification and recognition of seismic signals of vehicle targets in the outdoor environment. It can be proven that moving ground vehicles can be detected by measuring seismic signal, feature extraction of target seismic signal is correct and ANN data fusion is effective to solve the recognition and classification problem for moving ground targets. (C) 2004 Elsevier Ltd. All rights reserved.
The target tracking literature has traditionally been most interested in the "hit" model for the observations process, and the community has developed many techniques for data association. On the other hand,...
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ISBN:
(纸本)0819450774
The target tracking literature has traditionally been most interested in the "hit" model for the observations process, and the community has developed many techniques for data association. On the other hand, matched field processing (MFP) research has focused on signalprocessing with the main emphasis on target detection and localization. Treatments of combined tracking/MFP systems are not common. but most concentrate on signalprocessing, with the idea that a "track" is really a sequence or track-segment of detections that make sense from dynamics considerations. Thus, here we explore the MFP tracking problem, with the key that we attempt to use traditional target-tracking algorithms. In particular. we use an IMMPDAF-AI (interacting multiple-model probabilistic data association filter with amplitude information). It is shown that the use of such an advanced tracking algorithm - plus a number of MFP-specific refinements - produces tracking performance that is far superior to that obtained for a more traditional tracking (a strongest-neighbor Kalman filter), with the added advantage of a significantly reduced numerical load as measured in terms of the number of MFP replicas to be computed.
When the size of targets is comparable to the range resolution of monopulse radars, these targets should be considered as extended rather than point targets. If several closely-spaced targets fall within the same rada...
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When the size of targets is comparable to the range resolution of monopulse radars, these targets should be considered as extended rather than point targets. If several closely-spaced targets fall within the same radar beam and between adjacent matched filter samples in range, the full monopulse information from all of these samples can and should be used to resolve these targets, i.e., estimate the number of targets and their respective angles-of-arrival and ranges. To detect and localize multiple unresolved extended targets, we establish a model for monopulse radar returns from extended objects, and present a maximum likelihood estimator (MLE) to localize the targets. Rissanen's minimum description length (MDL) criterion will be used to decide the number of existing extended objects. We also derive the upper limit on the number of targets and their scattering centers that can be resolved, and we provide necessary conditions for these targets to be uniquely identified. We compare the new extended target monopulse processing scheme with previously developed point-target monopulse techniques in the simulations.
A new signalprocessing method using a single vector hydrophone is proposed for solving the problem of azimuth angle estimation for multiple targets based on a small aperture underwater *** method extends the aperture...
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A new signalprocessing method using a single vector hydrophone is proposed for solving the problem of azimuth angle estimation for multiple targets based on a small aperture underwater *** method extends the aperture from a single vector hydrophone into a half wavelength distance uniform linear array by decomposing the time-domain sample data from different channels of the *** extended array has a narrower space beam pattern than a single vector *** azimuths of spatial multiple targets are estimated by using the appended array snapshots under the condition of broadband or narrow band *** new method is robust because there is no need to correct the array *** analysis and computer simulations show that,the new algorithm has the ability to distinguish two incoherent targets with either narrow band or broadband signals in an isotropic noise *** algorithm provides a non-biased estimate with a high signal-to-noise ratio.
In many tracking applications. and particularly those in ballistic missile defense, one concern involves the continuous tracking of an object that separates into two objects. Reliable tracking without track breaks dem...
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ISBN:
(纸本)0819450774
In many tracking applications. and particularly those in ballistic missile defense, one concern involves the continuous tracking of an object that separates into two objects. Reliable tracking without track breaks demands early recognition of such a split, preferably well in advance of the two objects becoming resolvable by the radar. In previous work, signalprocessing techniques for detecting the presence of unresolved objects and angle-of-arrival estimation for unresolved targets have been developed for monopulse radars. In this paper, these techniques are reviewed and extended. Techniques for detecting the presence of unresolved objects are treated for the case of idealized resolution, in which all of the energy for a target is returned in a single range resolution sample or cell. The approaches work solely on monopulse angle statistics and rely on idealized range resolution. The requirement for idealized range resolution is relaxed by using joint statistics with adjacent matched filter returns. The AOA estimation and detection of the presence of unresolved objects for non-ideal resolution are then addressed. The performances are demonstrated using a high fidelity software simulation tool for target tracking.
Target detection is a key issue in processing hyperspectral images (HSIs). However, current spectral-identification-based algorithms are sensitive to noise during acquisition of the data. In most cases, the denoising ...
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Target detection is a key issue in processing hyperspectral images (HSIs). However, current spectral-identification-based algorithms are sensitive to noise during acquisition of the data. In most cases, the denoising algorithms cannot preserve smalltargets. In this paper, to overcome this problem, we propose a new algorithm which reduces noise to improve the target detection efficiency of HSI with smalltargets. First, a three-dimensional wavelet packet transform (3D-WPT) is used to decompose the HSI into several coefficient sets and models each coefficient set as a tensor. Then we exploit a powerful multilinear algebra model named parallel factor analysis (PARAFAC) to filter each tensor. The experiments conducted in both simulated and real-world hyperspectral images demonstrated the performance of the proposed method.
Radar detection and tracking of targets in the marine environment are common tasks performed to ensure the safe navigation of ships or monitor traffic in harbor areas. More recently, radar technology has been proposed...
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Radar detection and tracking of targets in the marine environment are common tasks performed to ensure the safe navigation of ships or monitor traffic in harbor areas. More recently, radar technology has been proposed to support the collision avoidance system of autonomous surface vehicles, which are characterized by severe constraints in terms of payload and space. The paper investigates the performance of a small and lightweight 24 GHz Frequency Modulated Continuous Wave (FMCW) Multiple-Input Multiple-Output (MIMO) radar, originally developed for automotive applications, to localize marine targets at short range. A complete signalprocessing strategy is presented combining MIMO radar imaging, detection, and tracking algorithms. The validation of the proposed signalprocessing chain is firstly performed thanks to numerical tests based on synthetic data. After, results of experimental trials carried out in the marine environment are reported. These results demonstrate that the considered radar together with the adopted signalprocessing strategy allows the localization of static targets and the tracking of moving targets with satisfactory performance, thus encouraging its use in marine environments.
In this paper, we apply higher ordered statistics filters to hyperspectral data to enable the detection of anomalous targets whose signatures are known. Each frame has subtracted from it an estimate based on an ordere...
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In this paper, we apply higher ordered statistics filters to hyperspectral data to enable the detection of anomalous targets whose signatures are known. Each frame has subtracted from it an estimate based on an ordered statistics filter;the resulting frames are then combined optimally based on the covariance data of the cube and the spectral signature of the target. We show that the effect of the ordered statistic filter is to eliminate false alarms at edge points.
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