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Effects Of Wind Turbines On High Frequency Surface Wave Radar
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Book Synopsis Effects of Wind Turbines on High Frequency Surface Wave Radar by : Defence R&D Canada - Ottawa
Download or read book Effects of Wind Turbines on High Frequency Surface Wave Radar written by Defence R&D Canada - Ottawa and published by Defence R&D Canada - Ottawa. This book was released on 2005 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mitigation of Ionospheric Effects on High Frequency Surface Wave Radar by :
Download or read book Mitigation of Ionospheric Effects on High Frequency Surface Wave Radar written by and published by . This book was released on 2006 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Frequency Surface Wave Radar (HFSWR) takes advantage of the di raction of electromagnetic waves over the conducting ocean surface to detect, locate, and track surface vessels beyond the line-of- sight horizon of the earth. However, long-range surface vessel detection is often confounded by radar clutter comprising echoes from the ionospheric plasma. In this paper, we characterize the angular spectrum of these re ections, and from this information deduce the signal-to-clutter processing gain that can be realized by various adaptive receive antenna array con gurations. In particular, it is shown that there is advantage to be realized by sampling ionospheric echoes with a planar two-dimensional array rather than a conventional linear one-dimensional HFSWR array. Using a planar array, the radar can distinguish high-elevation ionospheric clutter signals from low-elevation surface target echoes.
Book Synopsis Radar Signature Characterization from Wind Turbine Scattering by : Aale R. Naqvi
Download or read book Radar Signature Characterization from Wind Turbine Scattering written by Aale R. Naqvi and published by . This book was released on 2014 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth in the number of wind farms has raised significant concerns in the radar community due to their potential interference on radar systems. The motion of the turbine blades creates unwanted Doppler clutter that can interfere in the tracking of moving targets. Large turbine structures can also produce electromagnetic shadows that may make observing objects behind a wind farm difficult. Detailed characterization of the clutter is the first step towards effective mitigation techniques. The goal of this dissertation research is to gain a better understanding of the dynamic radar signatures resulting from scattering by wind turbines. First, the scattering characteristics of turbines in the presence of ground surface are studied. Image theory in conjunction with a shooting-and-bouncing ray code, Ahilo, is used to carry out the dynamic signature simulation. The observed features in the simulation are corroborated with laboratory model measurements. Second, the effects of higher order motions of a turbine undergoing rotation on the radar signatures are investigated and characterized. Mathematical models for the motions are proposed and used to simulate the joint time-frequency and inverse synthetic aperture radar characteristics of the turbine undergoing these motions. The motions are studied for an isolated turbine as well as for a turbine rotating above a ground. Selected motions are corroborated by laboratory model measurements. Next, a method to remove the dynamic clutter produced by wind turbines is presented. A physics-based basis is constructed to model the radar backscattering from a wind turbine. This basis is used in conjunction with the matching pursuit algorithm to iteratively remove the Doppler clutter due to wind turbines. The algorithm is tested using radar return generated using Ahilo. Finally, radar features of wind turbines are simulated and studied in the HF (high frequency) band. The features are presented in the range-Doppler plane for single as well as arrays of turbines. Doppler aliasing due to the limited pulse repetition frequency of HF radars is examined. Shadowing characteristics of arrays of turbines are simulated and analyzed. Electromagnetic modeling details including effects of thin-wire modeling, non-conducting turbine components, and the presence of a conducting ground surface are discussed.
Book Synopsis The High Frequency Surface Wave Radar Cross Section for Ocean Swell by : Chengxi Shen
Download or read book The High Frequency Surface Wave Radar Cross Section for Ocean Swell written by Chengxi Shen and published by . This book was released on 2013 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Extraction of Wind Speed from High Frequency Ground Wave Radar Oceanic Backscatter by : David W. Green
Download or read book Extraction of Wind Speed from High Frequency Ground Wave Radar Oceanic Backscatter written by David W. Green and published by . This book was released on 2005 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ionospheric Clutter Models for High Frequency Surface Wave Radar by : Shuyan Chen
Download or read book Ionospheric Clutter Models for High Frequency Surface Wave Radar written by Shuyan Chen and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High frequency surface wave radar (HFSWR), operating at frequencies between 3 and 30 MHz, has long been employed as an important ocean remote sensing device. These high frequency (HF) radars can provide accurate and real-time information for sea state monitoring and hard-target detection, which is greatly beneficial for planning and executing oceanographic projects, search and rescue events, and other commercial marine activities. Ideally, in HFSWR operation, the radio waves may be coupled with ocean waves and propagate along the curvature of the ocean surface with ranges well beyond 200 km. However, during transmission, a portion of the radar radiation may travel upwards to the ionosphere from the transmitting antenna. This may be partially reflected back to the receiving antennas directly (vertical propagation) or via the ocean surface (mixed-path propagation). This ionospheric clutter may significantly impact the performance of HFSWR. Furthermore, the high intensity and random behaviour of the ionospheric spectral contamination of radar echoes make the suppression of this kind of clutter challenging. In this thesis, comprehensive theoretical models of the ionospheric clutter are investigated. The physical influences of the ionospheric electron density on HF radar Doppler spectra are taken into account in the ionospheric reflection coefficient. Next, based on previous modeling involving the scattering of HF electromagnetic radiation from the ocean surface and a first-order mixed-path propagation theory, the second-order received electric field for mixed-path propagation is derived for a monostatic radar configuration. This is done by considering the reflection from the ionosphere and scattering on the ocean surface with second-order sea waves. Then, the field integrals are taken to the time domain, with the source field being that of a vertically polarized pulsed dipole antenna. Subsequently, the second-order received power model is developed by assuming that the ocean surface and the ionosphere may be modeled as stochastic processes. The ionospheric clutter model including a pulsed radar source is further investigated for the case of vertical propagation for a monostatic configuration and mixed-path propagation for a bistatic configuration. Next, a theoreticalmixed-path propagationmodel is developed by involving a frequencymodulated continuous waveform (FMCW) radar source. In order to investigate the power spectrum of the resulting ionospheric clutter and its relative intensity to that of the first-order ocean clutter, the normalized ionospheric clutter power is simulated. Numerical simulation results are provided to indicate the performance of the ionospheric clutter under a variety of radar operating parameters, ionospheric conditions and sea states.
Book Synopsis High Frequency Surface Wave Radar Propagation Over Arctic Seas by : Alan D. (Alan Douglas) Thomson
Download or read book High Frequency Surface Wave Radar Propagation Over Arctic Seas written by Alan D. (Alan Douglas) Thomson and published by Defence R&D Canada - Ottawa. This book was released on 2004 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Interaction of Ocean Waves and Wind by : Peter Janssen
Download or read book The Interaction of Ocean Waves and Wind written by Peter Janssen and published by Cambridge University Press. This book was released on 2004-10-28 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book was published in 2004. The Interaction of Ocean Waves and Wind describes in detail the two-way interaction between wind and ocean waves and shows how ocean waves affect weather forecasting on timescales of 5 to 90 days. Winds generate ocean waves, but at the same time airflow is modified due to the loss of energy and momentum to the waves; thus, momentum loss from the atmosphere to the ocean depends on the state of the waves. This volume discusses ocean wave evolution according to the energy balance equation. An extensive overview of nonlinear transfer is given, and as a by-product the role of four-wave interactions in the generation of extreme events, such as freak waves, is discussed. Effects on ocean circulation are described. Coupled ocean-wave, atmosphere modelling gives improved weather and wave forecasts. This volume will interest ocean wave modellers, physicists and applied mathematicians, and engineers interested in shipping and coastal protection.
Book Synopsis Suppression of Power Line Harmonic Interference in HF Surface-wave Radar by : Hank Leong
Download or read book Suppression of Power Line Harmonic Interference in HF Surface-wave Radar written by Hank Leong and published by . This book was released on 1992 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Adaptive Processing in High Frequency Surface Wave Radar by : Oliver Saleh
Download or read book Adaptive Processing in High Frequency Surface Wave Radar written by Oliver Saleh and published by . This book was released on 2008 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Frequency Surface Wave Radar(HFSWR) is a radar technology that offers numerous advantages for low-cost, medium accuracy surveillance of coastal waters beyond the exclusive economic zone. However, target detection and tracking is primarily limited by ionospheric interference. Ionospheric clutter is characterized by a high degree of nonhomogeneity and nonstationarity, which makes its suppression difficult using conventional processing techniques. Space-time adaptive processing techniques have enjoyed great success in airborne radar, but have not yet been investigated in the context of HFSWR. This thesis is primarily concerned with the evaluation of existing STAP techniques in the HFSWR scenario and the development of a new multistage adaptive processing approach, dubbed the Fast Fully Adaptive (FFA) scheme, which was developed with the particular constraints of the HFSWR interference environment in mind. To this end an analysis of measured ionospheric clutter is conducted, which allows for a characterization of the underlying statistical behavior of the HFSWR interference. Several popular low-complexity STAP algorithms are assessed for their performance in HFSWR. Focus is then shifted towards the development of the FFA approach. Three different spatio-temporal partitioning schemes are introduced. A thorough investigation of the performance of the FFA is conducted in both the airborne radar and HFSWR setups under a variety of sample-support scenarios.
Book Synopsis Wave Dynamics and Radio Probing of the Ocean Surface by : O. M. Phillips
Download or read book Wave Dynamics and Radio Probing of the Ocean Surface written by O. M. Phillips and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1960, Dr. George Deacon ofthe National Institute ofOceanography in England organized a meeting in Easton, Maryland that summarized the state of our understanding at that time of ocean wave statistics and dynamics. It was a pivotal occasion: spectral techniques for wave measurement were beginning to be used, wave-wave interactions hadjust been discovered, and simple models for the growth of waves by wind were being developed. The meeting laid the foundation for much work that was to follow, but one could hardly have imagined the extent to which new techniques of measurement, particularly by remote sensing, new methods of calculation and computation, and new theoretical and laboratory results would, in the following twenty years, build on this base. When Gaspar Valenzuela of the V. S. Naval Research Laboratory perceived that the time was right for a second such meeting, it was natural that Sir George Deacon would be invited to serve as honorary chairman for the meeting, and the entire waves community was delighted at his acceptance. The present volume contains reviewed and edited papers given at this second meeting, held this time in Miami, Florida, May 13-20, 1981, with the generous support of the Office of Naval Research, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration.
Book Synopsis Adaptive Processing in High Frequency Surface Wave Radar by : Oliver S. Saleh
Download or read book Adaptive Processing in High Frequency Surface Wave Radar written by Oliver S. Saleh and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Frequency Surface Wave Radar (HFSWR) is a radar technology that offers numerous advantages for surveillance of coastal waters beyond the exclusive economic zone. However, target detection and tracking is primarily limited by ionospheric interference. Ionospheric clutter is characterized by a high degree of nonhomogeneity and nonstationarity, which makes its suppression difficult using conventional processing techniques. Space-time adaptive processing techniques have enjoyed great success in airborne radar, but have not yet been investigated in the context of HFSWR. This thesis is primarily concerned with the evaluation of existing STAP techniques in the HFSWR scenario and the development of a new multistage adaptive processing approach, dubbed the Fast Fully Adaptive (FFA) scheme, which was developed with the particular constraints of the HFSWR interference environment in mind. Three different spatio-temporal partitioning schemes are introduced and a thorough investigation of the performance of the FFA is conducted.
Author :National Academies of Sciences Engineering and Medicine Publisher : ISBN 13 :9780309275484 Total Pages : pages Book Rating :4.2/5 (754 download)
Book Synopsis Wind Turbine Generator Impacts to Marine Vessel Radar by : National Academies of Sciences Engineering and Medicine
Download or read book Wind Turbine Generator Impacts to Marine Vessel Radar written by National Academies of Sciences Engineering and Medicine and published by . This book was released on 2022-11-22 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Mixing written by Michael Meredith and published by Elsevier. This book was released on 2021-09-16 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean Mixing: Drivers, Mechanisms and Impacts presents a broad panorama of one of the most rapidly-developing areas of marine science. It highlights the state-of-the-art concerning knowledge of the causes of ocean mixing, and a perspective on the implications for ocean circulation, climate, biogeochemistry and the marine ecosystem. This edited volume places a particular emphasis on elucidating the key future questions relating to ocean mixing, and emerging ideas and activities to address them, including innovative technology developments and advances in methodology. Ocean Mixing is a key reference for those entering the field, and for those seeking a comprehensive overview of how the key current issues are being addressed and what the priorities for future research are. Each chapter is written by established leaders in ocean mixing research; the volume is thus suitable for those seeking specific detailed information on sub-topics, as well as those seeking a broad synopsis of current understanding. It provides useful ammunition for those pursuing funding for specific future research campaigns, by being an authoritative source concerning key scientific goals in the short, medium and long term. Additionally, the chapters contain bespoke and informative graphics that can be used in teaching and science communication to convey the complex concepts and phenomena in easily accessible ways. Presents a coherent overview of the state-of-the-art research concerning ocean mixing Provides an in-depth discussion of how ocean mixing impacts all scales of the planetary system Includes elucidation of the grand challenges in ocean mixing, and how they might be addressed
Book Synopsis The Effects of Wind Turbine Farms on Air Defence Radars by :
Download or read book The Effects of Wind Turbine Farms on Air Defence Radars written by and published by . This book was released on 2005 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: The UK Government supports the introduction of wind turbine farms as part of its alternative energy strategy but existing Ministry of Defense (MoD) Guidelines restrict planning consent for wind turbine farms within 60% of maximum instrumented range (interpreted as 74 km) and line of sight from primary surveillance radars. However, wind farm developers are increasingly questioning the validity of current Guidelines. Consequently, a Trial was conducted by the Air Command and Control Operational Evaluation Unit (Air C2 OEU) in response to a tasking from the Directorate of Counter Terrorism and United Kingdom Operations (D CT&UK Ops) to determine the effects of wind turbine farms on Air Defense (AD) radars. The aim of the Trial was to determine the effects of wind turbine farms on AD radars by considering the effects of wind turbine farms on radar performance with regard to probability of detection, tracking and displayed effects, the effects on low-level coverage due to the wind turbine farms and system set-up and observed displayed effects. It was confirmed that on the T101 radar, primary radar returns from aircraft having a low Radar Cross Section (Hawk T Mk 1a and Tucano T Mk 1) are lost when flying over wind turbines, regardless of the aircraft's height. The cause of this effect is believed to be as a result of excessive returns from the wind turbines being received in the elevation sidelobes of the radar. As a result of this Trial, the MoD has provisionally ceased automatic approval of wind turbine developments beyond 74 km but within Line of Sight from an AD radar.
Book Synopsis Observation by HF Radar of the Phillips Resonance Mechanism for Generation of Wind Waves by :
Download or read book Observation by HF Radar of the Phillips Resonance Mechanism for Generation of Wind Waves written by and published by . This book was released on 1980 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
