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Enhanced Detection Of Small Targets In Ocean Clutter For High Frequency Surface Wave Radar
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Book Synopsis Enhanced Detection of Small Targets in Ocean Clutter for High Frequency Surface Wave Radar by :
Download or read book Enhanced Detection of Small Targets in Ocean Clutter for High Frequency Surface Wave Radar written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The small target detection in High Frequency Surface Wave Radar is limited by the presence of various clutter and interference. Several novel signal processing techniques are developed to improve the system detection performance. As an external interference due to local lightning, impulsive noise increases the broadband noise level and then precludes the targets from detection. A new excision approach is proposed with modified linear predictions as the reconstruction solution. The system performance is further improved by de-noising the estimated covariance matrix through signal property mapping method. The existence of non-stationary sea clutter and ionospheric clutter can result in excessive false alarm rate through the high sidelobe level in adaptive beamforming. The optimum threshold discrete quadratic inequality constraints method is proposed to guarantee the sidelobe-controlling problem consistently feasible and optimal. This constrained optimization problem can be formulated into a second order cone problem with efficient mathematical solution. Both simulation and experimental results validate the improved performance and feasibility of our method. Based on the special noise characteristics of High Frequency radar, an adaptive switching Constant False Alarm Rate detector is proposed for targets detection in the beamformed range-Doppler map. The switching rule and adaptive footprint are applied to provide the optimum background noise estimation. For this new method about 14% probability of detection improvement has been verified by experimental data, and meanwhile the false alarm rate is reduced significantly compared to the original CFAR. The conventional Doppler processing has difficulty to recognize a target if its frequency is close to a Bragg line. One detector is proposed to solve this co-located co-channel resolvability problem under the assumption that target/clutter have different phase modulation. Moreover with the pre-whitening processing, the Rever.
Book Synopsis High resolution methods for small target detection and estimation in high frequency radar by : Jian Wang (Ph. D.)
Download or read book High resolution methods for small target detection and estimation in high frequency radar written by Jian Wang (Ph. D.) and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The detection and tracking of small slow moving targets by High Frequency Surface Wave radar are limited by the presence of a dominate sea clutter spectrum. The ocean surface behaves as a distributed source in contrast to targets that are point sources. It is shown that by mapping data to eigenspaces, the sea clutter level decreases due to its nondeterministic behaviour while point targets' levels remain unchanged. The high resolution (subspace-based or eigenspace) methods and frequency tracking method for slowly time varying frequencies are evaluated to suppress this sea clutter to enhance detection of weak signals. Experimental results verify the advantage of subspace-based methods over the traditional processing techniques. Conventional subspace methods can be utilized to enhance the detection, but they deteriorate dramatically in the presence of correlated sea clutter. In our thesis some adaptive sea clutter pre-filtering schemes are introduced which improve the threshold and accuracy of subsequent subspace methods. Both simulated and real ship targets are used to verify the effectiveness of our proposed method. Furthermore, we propose another novel subspace algorithm to estimate the directions of arrival of superimposed cisoidal radar echoes from far-field targets in the radar pulse domain. The improvement provided by this algorithm is based on the use of a state space model that more accurately represents the received Doppler radar array signal prior to spatial processing such as MUSIC. A 2-d (spatial and temporal) pre-filtering matrix is structured and applied to the received array signal, which is finally combined with the high-resolution (MUSIC) method for DOA estimation. Lower resolution threshold and estimation variance are achieved by this algorithm compared to conventional beam-space MUSIC and sensor-space MUSIC. A simplified theoretical resolution threshold is derived, and both the theory and simulations verify the effectiveness of our proposed algorithm. Results from an experiment using a simulated target superimposed on real HF radar sea clutter also confirm the algorithm.
Book Synopsis Time-domain Modelling of Ocean Clutter for Ground Wave Radar by :
Download or read book Time-domain Modelling of Ocean Clutter for Ground Wave Radar written by and published by . This book was released on 1989 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detection performance of high frequency ground wave (HFGW) radar systems, for over-the-horizon detection of surface targets, is limited by the back scattering returns from the ocean surface. An improved modelling of the ocean clutter is the key to enhanced target detection with HFGW radar; this would enable clutter suppression techniques to be refined and a higher signal-to-noise ratio to be achieved. This paper proposes a wave packet model for the dominant components of the ocean back scattering signal and suggests a technique to exploit this non-stationary characteristic of the ocean clutter to improve target detection performance. The technique is based on the Wigner-Ville distribution, which is an emerging tool for non-stationary spectral analysis. Results are presented to demonstrate the enhanced detection performance of the proposed technique.
Book Synopsis Adaptive Waveform Design and CFAR Processing for High Frequency Surface Wave Radar by : Alison Cheeseman
Download or read book Adaptive Waveform Design and CFAR Processing for High Frequency Surface Wave Radar written by Alison Cheeseman and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: High frequency surface wave radar (HFSWR), used for coastal surveillance, operates in a challenging environment as the clutter signals returned from the ocean surface can be several orders of magnitude larger than returns from targets. Reliably detecting small boats in severe sea states, is therefore quite difficult. In this thesis we take a two-fold approach to improving the detection performance of Raytheon Canada's third generation HFSWR system. First, we consider the design of transmit waveforms with improved range resolution, thus reducing the area of the clutter cell. We develop an algorithm to design practical spectrally-compliant waveforms which achieve high bandwidths while simultaneously avoiding interference with concurrent communications users. We then propose a new detection algorithm based on the best known statistical model for sea clutter, the K-distribution. We show that both the proposed transmit waveforms and detection algorithm can lead to improved detection performance in a sea clutter environment.
Book Synopsis A Novel Approach for the Detection of Maneuvering Air Targets in Sea-clutter Using High-frequency Surface-wave Radar by : T. Thayaparan
Download or read book A Novel Approach for the Detection of Maneuvering Air Targets in Sea-clutter Using High-frequency Surface-wave Radar written by T. Thayaparan and published by Defence R&D Canada - Ottawa. This book was released on 2005 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Radar Sea Clutter by : Luke Rosenberg
Download or read book Radar Sea Clutter written by Luke Rosenberg and published by IET. This book was released on 2021-12-17 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents comprehensive coverage of new research into sea clutter characterisation and modelling, radar performance prediction and maritime target detection. The book also includes a summary of sea-clutter scattering characteristics and datasets provided that can be used for modelling.
Book Synopsis Adaptive Filtering for Clutter Suppression in High Frequency Radar by :
Download or read book Adaptive Filtering for Clutter Suppression in High Frequency Radar written by and published by . This book was released on 1990 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: High frequency (HF) radar has the unique potential for over-the horizon detection of ocean surface targets. However, ocean waves are also strong reflections for HF radar and this high clutter level has limited its application for target detection. New results from the time domain analysis of ocean clutter show that it can be modelled as two angle modulated signals; this may be used to selectively suppress the clutter component, and enhance the target detection performance. The practical implementation of clutter suppression, based upon this model, involves tracking of multiple time-varying sinusoids. This paper discusses an adaptive filtering technique to track time-varying sinusoids and presents initial results.
Book Synopsis Time Domain Analysis of Ocean Clutter in High Frequency Radar by :
Download or read book Time Domain Analysis of Ocean Clutter in High Frequency Radar written by and published by . This book was released on 1990 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: High frequency (HF) radar has the unique potential for over-the horizon detection of ocean surface targets. However, ocean waves are also strong reflectors for HF radar and this high clutter level has limited its application for target detection. This paper describes further detailed investigations of the time-varying behaviour of the ocean clutter and shows that the clutter can be modelled by two narrowband signals, with time-carrying frequencies, centred around the two `Bragg' frequencies. It also describes how, in the presence of a target signal, simple time-domain processing may be used to selectively suppress the dominant clutter signals.
Book Synopsis Suppression of Ocean Clutter in High Frequency Radar by :
Download or read book Suppression of Ocean Clutter in High Frequency Radar written by and published by . This book was released on 1990 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strong ocean clutter levels restrict the target detection capabilities of high frequency (HF) radar. A recently-proposed time-domain model for the ocean clutter may be used to selectively suppress the clutter component and enhance the target detection performance. This paper discusses some techniques in the practical implementation of clutter suppression, based upon this model, and presents initial results.
Book Synopsis Target Detection by Marine Radar by : John N. Briggs
Download or read book Target Detection by Marine Radar written by John N. Briggs and published by IET. This book was released on 2004-12-03 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radar is a legal necessity for the safe navigation of merchant ships, and within vessel traffic services is indispensable to the operation of major ports and harbours. Target Detection by Marine Radar concentrates solely on civil marine operations and explains how marine surveillance radars detect their targets. The book is fully illustrated and contains worked examples to help the reader understand the principles underlying radar operation and to quantify the importance of factors such as the technical features of specific equipment, the weather, target reflection properties, and the ability of the operator. The precision with which targets are positioned on the radar screen and with which their progress is tracked or predicted depends on how definitely they have been detected, therefore a whole chapter has been devoted to the issue of accuracy. The various international regulations governing marine radar are examined, a brief historical background is given to modern day practice and the book doses with a discussion of the ways in which marine radar may develop to meet future challenges.
Download or read book Sea Clutter written by Keith D. Ward and published by IET. This book was released on 2006-06-21 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sea Clutter: Scattering, the K Distribution and Radar Performance examines the statistics of radar scattering from the sea surface in terms of their relevance to radar operating in a maritime environment; including remote sensing, surveillance and targeting applications. A lot of the work in the book is based on the compound Kdistribution model for the amplitude statistics of sea clutter. In addition, the book addresses the specification of performance required by customers and the measurement of performance of systems supplied to customers.
Book Synopsis Reliable Ship Target Detection for High Frequency Surface Wave Radars by : Jan Oliver Hinz
Download or read book Reliable Ship Target Detection for High Frequency Surface Wave Radars written by Jan Oliver Hinz and published by . This book was released on 2014 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effects of Sea Clutter on the Performance of HF Surface Wave Radar in Ship Detection and the Implication on the Radar Design by : Hank Leong
Download or read book The Effects of Sea Clutter on the Performance of HF Surface Wave Radar in Ship Detection and the Implication on the Radar Design written by Hank Leong and published by . This book was released on 2007 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Non-Rayleigh sea clutter by : G. V. Trunk
Download or read book Non-Rayleigh sea clutter written by G. V. Trunk and published by . This book was released on 1976 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Detection of Small Targets in Sea Clutter Limited Environments Using Phase Information by : Brian L. Reid
Download or read book Detection of Small Targets in Sea Clutter Limited Environments Using Phase Information written by Brian L. Reid and published by . This book was released on 1995 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current techniques used to discriminate between sea clutter and targets, based on using the amplitude of the reflected signal, are described and applied to data collected experimentally. A new method which uses information contained in the phase of the reflected energy is described and is also applied to this data set and a significant improvement in the ability to detect a small target within this data is demonstrated. Issues associated with the implementation of this algorithm in an existing radar system are then considered and several feasible approaches are described.
Book Synopsis Ocean-clutter Model for High-frequency Radar by :
Download or read book Ocean-clutter Model for High-frequency Radar written by and published by . This book was released on 1991 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inverse problem of extracting the ocean wave-length spectrum from the high-frequency (HF) radar clutter signal involves inventing a nonlinear integral equation. The strong ocean-clutter signal also eliminates the application of HF radar to target detection. This paper describes a detailed investigation of the time-varying behaviour of the ocean clutter and shows that the ocean-clutter can be modeled by two narrowband signals, with time-varying frequencies, centred around the two Bragg frequencies. It is demonstrated that the spectrum of such an angle-modulated signal agrees closely with the spectrum of HF radar data and accounts for the characteristics corresponding to both the first- and second-order scattering peaks.
Book Synopsis Time-frequency-based Detection of Fast Maneuvering Targets Using High-frequency Surface-wave Radar by : T. Thayaparan
Download or read book Time-frequency-based Detection of Fast Maneuvering Targets Using High-frequency Surface-wave Radar written by T. Thayaparan and published by . This book was released on 2010 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
