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Mitigation Of Ionospheric Effects On High Frequency Surface Wave Radar
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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 Two-dimensional Adaptive Processing for Ionospheric Clutter Mitigation in High Frequency Surface Wave Radar by : R. J Riddolls
Download or read book Two-dimensional Adaptive Processing for Ionospheric Clutter Mitigation in High Frequency Surface Wave Radar written by R. J Riddolls and published by . This book was released on 2008 with total page 16 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 Radio Propagation Effects Due to Ionospheric Waves by : Kurt Toman
Download or read book Radio Propagation Effects Due to Ionospheric Waves written by Kurt Toman and published by . This book was released on 1970 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic-gravity waves in the ionosphere create moving, undulating, reflecting surfaces. Overhead passage of such surfaces causes variations of amplitude, phase, and frequency of reflected radio waves. The patterns of these variations change with the characteristics of the reflecting surface. For the study and prediction of these patterns, computer experiments were carried out to simulate the effects of sinusoidal reflecting surfaces on propagating radio waves. The simulated parameters included field strength and path length and its derivative. The results are compared with high-frequency measurements made over an oblique, ionospheric transmission between Ottawa, Canada, and Bedford Mass. (Author).
Book Synopsis Signal Processing Methods to Improve Ocean Surface Wave Estimation from a High Frequency Surface Wave Radar by :
Download or read book Signal Processing Methods to Improve Ocean Surface Wave Estimation from a High Frequency Surface Wave Radar written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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 THE EFFECTS OF IONOSPHERIC CHANGE ON HIGH FREQUENCY RADAR OBSERVATIONS by : Institute for Telecommunication Sciences and Aeronomy (U.S.)
Download or read book THE EFFECTS OF IONOSPHERIC CHANGE ON HIGH FREQUENCY RADAR OBSERVATIONS written by Institute for Telecommunication Sciences and Aeronomy (U.S.) and published by . This book was released on 1966 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
Author :National Academies of Sciences, Engineering, and Medicine Publisher :National Academies Press ISBN 13 :0309373085 Total Pages :254 pages Book Rating :4.3/5 (93 download)
Book Synopsis A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum by : National Academies of Sciences, Engineering, and Medicine
Download or read book A Strategy for Active Remote Sensing Amid Increased Demand for Radio Spectrum written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2015-09-21 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Active remote sensing is the principal tool used to study and to predict short- and long-term changes in the environment of Earth - the atmosphere, the oceans and the land surfaces - as well as the near space environment of Earth. All of these measurements are essential to understanding terrestrial weather, climate change, space weather hazards, and threats from asteroids. Active remote sensing measurements are of inestimable benefit to society, as we pursue the development of a technological civilization that is economically viable, and seek to maintain the quality of our life. A Strategy for Active Remote Sensing Amid Increased Demand for Spectrum describes the threats, both current and future, to the effective use of the electromagnetic spectrum required for active remote sensing. This report offers specific recommendations for protecting and making effective use of the spectrum required for active remote sensing.
Book Synopsis Machine Learning and Intelligent Communications by : Xuemai Gu
Download or read book Machine Learning and Intelligent Communications written by Xuemai Gu and published by Springer. This book was released on 2018-01-20 with total page 699 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two volume set constitutes the refereed post-conference proceedings of the Second International Conference on Machine Learning and Intelligent Communications, MLICOM 2017, held in Weihai, China, in August 2017. The 143 revised full papers were carefully selected from 225 submissions. The papers are organized thematically in machine learning, intelligent positioning and navigation, intelligent multimedia processing and security, intelligent wireless mobile network and security, cognitive radio and intelligent networking, intelligent internet of things, intelligent satellite communications and networking, intelligent remote sensing, visual computing and three-dimensional modeling, green communication and intelligent networking, intelligent ad-hoc and sensor networks, intelligent resource allocation in wireless and cloud networks, intelligent signal processing in wireless and optical communications, intelligent radar signal processing, intelligent cooperative communications and networking.
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 Adaptive Processing in High Frequency Surface Wave Radar by :
Download or read book Adaptive Processing in High Frequency Surface Wave Radar written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Communications, Signal Processing, and Systems by : Qilian Liang
Download or read book Communications, Signal Processing, and Systems written by Qilian Liang and published by Springer Nature. This book was released on 2021-06-07 with total page 2070 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together papers presented at the 2020 International Conference on Communications, Signal Processing, and Systems, which provides a venue to disseminate the latest developments and to discuss the interactions and links between these multidisciplinary fields. Spanning topics ranging from communications, signal processing and systems, this book is aimed at undergraduate and graduate students in Electrical Engineering, Computer Science and Mathematics, researchers and engineers from academia and industry as well as government employees (such as NSF, DOD and DOE).
Book Synopsis Characterization of Ionospheric Clutter in HF Surface-wave Radar by : Chan, Hing C
Download or read book Characterization of Ionospheric Clutter in HF Surface-wave Radar written by Chan, Hing C and published by Defence R&D Canada - Ottawa. This book was released on 2003 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annali di geofisica written by and published by . This book was released on 2009 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Correction for Ionospheric Refraction for COBRA DANE by : Richard S. Allen
Download or read book Correction for Ionospheric Refraction for COBRA DANE written by Richard S. Allen and published by . This book was released on 1977 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hit-to-hit correction for range error arising from ionospheric refraction has been developed for the COBRA DANE radar. First a FORTRAN procedure was developed to compute monthly median refraction corrections over the field of view. These were provided to the radar in the form of equivalent look-up tables. A FORTRAN program was developed for the radar computed index values for each target position (azimuth, elevation, and range) and a correction was determined for each radar hit. This procedure removed about 75 percent of the monthly mean ionospheric effect. A further reduction was then made by using first and update factor determined by the Air Force Global Weather Central and then a more accurate update derived from a two-frequency calibration made by the radar itself. These procedures are shown to be capable of removing up to 90 percent of the mean ionospheric effect.
