Cross-eye jamming is an Electronic Attack (EA) technique that induces an angular error in the radar being jammed. The main benefit of cross-eye jamming is that it is effective against monopulse tracking radars, which are largely immune to other forms of jamming. The objective of this research is to gain a complete understanding of cross-eye jamming so that systems that might be developed in future can be properly specied. The main contribution of this work is a comprehensive mathematical and experimental study of retrodirective cross-eye jamming. The mathematical analysis considers all aspects of an isolated, single-loop, retrodirective cross-eye jamming engagement, thereby avoiding the approximations inherent in other cross-eye jamming analyses. Laboratory experiments that accurately represent reality by using the radar for both transmission and reception, and simulating a true retrodirective cross-eye jammer were performed to validate the theoretical analysis. Lastly, the relationship between the angular error induced in the radar being jammed and the matching required from a cross-eye jammer system is explored. The most important conclusion of this work is that the traditional analyses of cross- eye jamming are inaccurate for the conditions under which cross-eye jammers operate. These inaccuracies mean that the traditional analyses are overly conservative, particularly at short ranges and for high cross-eye gains, suggesting that practical cross-eye jammers can be realised more easily than is generally believed. / Thesis (PhD)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted

Thesis (Ph. D.)--University of Adelaide, 1986. / Includes bibliographical references (leaves 163-172).

Thesis (MScEng) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT: The development of a small, cost effective short range FM-CW radar as well as the design and optimization of a double helix antenna is discussed. The FM-CW radar operates at Sband (2450 - 2550 MHz) and is limited at a maximum transmitted power of 5 dBm. The system is required to detect reflections from objects up to a 30 m range. This was made possible largely by the effective high gain antenna design and improved system isolation between the transmitted and received signals. The complete design process from fundamental requirements, through various simulations and system analysis to the final electronic circuit is discussed. The design was also built and measured in the laboratory and initial field measurements were taken. The following aspects were considered: Relation between the beat frequency and various FM-CW radar system parameters based on the theory, preliminary measurements and simulations. Radar component assessment and design. Design of a low cost Lange coupler that isolates the system's transmit and receive signals, which operates as a 90° hybrid and is used to feed a dual-fed circularly polarized patch antenna. A circularly polarized patch antenna and double helix antenna were designed, built and measured in an anechoic chamber. The antennas were implemented in the final radar system and compared on the basis of their contribution to the system's performance. Integrating the final radar system on a circular 60 mm diameter PCB with a double helix antenna mounted on top. The final radar system is able to measure range up to 40 m and meets all the design requirements. The signal processing of the measured beat frequency, however, can be taken further. / AFRIKAANSE OPSOMMING: Die ontwikkeling van 'n klein, koste effektiewe kort-afstand FM-CW radar, sowel as die onwerp en optimalisering van 'n dubbele heliks-antenna word bespreek. Die FM-CW radar werk by S-band (2450 - 2550 MHz) en is beperk tot 'n maksimum uitsaaidrywing van 5 dBm. Van die stelsel word vereis om weerkaatsings van voorwerpe tot op 'n afstand van 30 m waar te neem. Dit is grootliks moontlik gemaak deur die hoë aanwins antenna-ontwerp en verbeterde isolasie tussen die stelsel se uitsaai- en ontvangseine. Die volledige ontwerpsproses van die fundamentele vereistes af tot die finale elektroniese stroombaan word bespreek. Verskeie simulasies andstelselanalises is gebruik om die finale FM-CW radar te realiseer. Die ontwerp is vervolgens in die laboratorium gebou en gemeet en aanvangsveldmetings is geneem. Die volgende aspekte is in nagevors: Verband tussen die puls-frekwensie en verskeie FM-CW radar stelselparameters gebaseer op die teorie, inleidende metings en simulasies. Ontleding van verskeie radarkomponente en -stelselontwerp. Ontwerp van 'n lae koste Lange-koppelaar met die doelom die stelsel se uitsaai- en ontvangseine te isoleer. Die Lange-koppelaar dien as 'n 90° hibriede wat gebruik word om 'n dubbele-voer sirkulêr gepolariseerde mikrostrookantenna aan te dryf. Verder is 'n sirkulêr gepolariseerde mikrostrook-antenna en 'n dubbele heliksantenna ontwerp en opgemeet in 'n anarqoïese kamer. Beide antennas is geïmplimenteer in die finale radarstelsel en is vergelyk op grond van hulle rol in die stelsel se funksionering. Die finale stelsel is geïntegreer en gebou op 'n ronde 60 mm deursnit PCB met 'n dubbele helix-antenna bo-op gemonteer. Die finale radarstelsel kan afstand tot op 40 meter bepaal en voldoen aan al die gestelde vereistes. Seinverwerking van die gemete puls-frekwensie kan nog verder ontwikkel word.

Remote detection and tracking of wingtip generated wake vortices is important for hazard avoidance especially near airports. Aircraft that fly through these hazardous vortices experience sudden induced roll. Experiments have demonstrated that there is sufficient radar cross section for remote detection at frequencies ranging from VHF to C band (100 MHz to 5 GHz). The mechanism that yields this radar cross section is Bragg scattering from the index of refraction variations due to the atmospheric water vapor and potential temperature fields being mixed by the wake vortex system. Refractive index variations of the size that correspond to half the operating radar wavelength produce the observed radar return. Previous analysis has postulated turbulence within the wake vortex to be the generator of the index of refraction variations. In this work, a new mechanism is identified that does not assume turbulence within the wake vortex system. This "laminar flow mechanism" causes refractive index structuring that stretches into successively smaller spirals over time as the wake vortex system swirls and descends through the stratified atmosphere. The results are quantitatively consistent with experimental data. Results indicate that this new mechanism has a sharply peaked doppler spectrum which is encouraging for coherent detection by doppler radar. / Ph. D.

<p dir="ltr">In this study we seek to evaluate the dry snow method of Z_DR calibration using dry snow as a target for X-band radars in comparison to vertical calibration scans. Numerous dates in the 2021 year were analyzed using the X-band Teaching and Research Radar (XTRRA) located on the Purdue University campus utilizing both vertical scans and azimuthal scans of dry snow. It was found that dry snow is still a potentially viable X-band calibration but several caveats, such as significant impacts from the protective dome around the radar, need to be addressed in order to make these results more robust.</p>

Call number: LD2668 .T4 1964 M16 / Master of Science

International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Vessel Traffic Management System is a cooperative effort of the Naval Undersea Warfare Center and the Naval Air Warfare Center Aircraft Division, funded by the OSD's Test Technology Development and Demonstration Program. The project is establishing the capability to acquire ship tracking information from numerous sources (GPS and radar target extractors), and combine them into a comprehensive, integrated view of the range safety target area. The consolidated tracking information will be transmitted to range safety vessel personnel and presented on portable display systems to aid in clearing the surveillance area of unauthorized vessels. The communications module is media independent in that positional and image data can be routed via RF modem, cellular phone, Intranet or Internet, singly or in any combination. The software systems for data acquisition, display and control are also platform independent, with the system under development operating under WindowsNT and Windows95. Additionally, the use of Java and VRML tools permits a user to display data (including three dimensional presentations of the data) without requiring the applications software. This system has numerous applications including range safety, commercial vessel traffic management, port authority and services monitoring, and oceanographic data gathering.

The hardware and software for a computer controlled optical radar, or lidar, system are described. The system builds on a previously installed pulsed ruby backscatter lidar, capable of acquiring data at controlled azimuth and elevation angles through the atmosphere. The described system replaces hardwired logic with computer control. Two coupled computers are used to allow a degree of real time control while data are processed. One of these computers reads and controls mount elevation angle, reads the laser energy monitor, and senses firing of the laser. The other computer serves as a user interface, and receives the lidar return data from a digitizer and memory, and the angle and energy information from the other computer. The second computer also outputs data to a disc drive. The software provided with the system is described, and the feasibility of additional software for both control and data processing is explored. Particular attention is given to data integrity and instrument and computer operation in the presence of the high energy pulses used to drive the laser. A previously described laser energy monitor has been improved to isolate it from laser transients. Mount elevation angles are monitored with an absolute angle readout. As a troubleshooting aid, a simulator with an output that approximates the lidar receiver output was developed. Its output is digitally generated and provides a known repetitive signal. Operating procedures are described for standard data acquisition, and troubleshooting is outlined. The system can be used by a relatively inexperienced operator; English sentences are displayed on the system console CRT terminal to lead the operator through data acquisition once the system hardware is turned on. A brief synopsis of data acquired on the system is given. Those data are used as the basis of other referenced papers. It constitutes soundings for over one hundred days. One high point has been operation of the system in conjunction with a balloon borne atmospheric particulate sampling package. The system has also been used occasionally as the transmitter of a lidar system with physically separated receiver and transmitter.

La pollution maritime est l’un des principaux accidents qui affectent l’environnement maritime pendant une longue période. Il est essentiel que les systèmes de détection et de surveillance des déversements d'hydrocarbures interviennent rapidement pour contenir le danger. Ces systèmes utilisent plusieurs techniques et capteurs, les plus récents étant ceux réalisés à distance à l'aide de systèmes satellitaires et aéroportés. L'Agence européenne pour la sécurité maritime (EMSA) a lancé en 2016 la nécessité d'utiliser un système complémentaire, utilisant des drones, aux systèmes de surveillance maritime actuels.Dans nos travaux, nous proposons l’utilisation des drones comme système de détection des déversements d’hydrocarbures. Le radar basé sur un drone permettra une évaluation rapide et le traitement des données en temps réel de la zone où le drapeau de possibles déversements est levé par des témoins. L' échographie en parallèle peut être utilisée pour couvrir une grande surface dans un moment critique. De plus, l' échographie à l'aide de drones offre une résolution spatiale élevée par rapport à un satellite et présente l'avantage principal d'un coût relativement réduit par rapport aux systèmes de détection aéroportés spécialisés. Les drones peuvent être désignés comme systèmes nadir (émission et réception à angle nul par rapport à la normale). Étant largement indépendants de la rugosité de surface, les rendements des systèmes nadir (ou quasi-nadir) bénéficieront de la prédominance de la diffusion spéculaire et permettront une détection même par vent très faible. Les mêmes conditions sont considérées comme inappropriées pour la détection à l'aide d'autres techniques récentes.Dans cette thèse, nous présentons une nouvelle approche probabiliste qui utilise un radar à large bande d'aspect nadir pour les applications de détection de la pollution maritime. L’approche proposée combine un modèle de diffusion monocouche et des statistiques bayésiennes afin d’évaluer la probabilité de détection de marées noires, dans une plage plausible d’épaisseurs, sur l’eau de mer. Nous présentons un cadre d’algorithmes qui utilise des mesures de la valeur de réflectivité pour détecter les déversements de pétrole. L'infrastructure prend en charge une ou plusieurs mesures collectées à une ou plusieurs fréquences dans les bandes C et X. L'analyse des performances des trois types de détecteurs (simple, double et tri-fréquence) est effectuée. L'analyse des résultats obtenus à partir des interfaces de surfaces planes et rugueuses est également présentée.Nous complétons les algorithmes de détection par une nouvelle approche visant à estimer l’épaisseur de la nappe de pétrole. Nous présentons des estimateurs à probabilité unique, double et multifréquences maximum. Ces derniers utilisent l'algorithme de distance minimum euclidienne, dans des ensembles de constellation prédéfinis 1-D, 2-D ou K-D, sur des réflectivités simulées pour estimer l'épaisseur de la marée noire. Les algorithmes dérivés sont présentés et testés à l'aide d'une simulation de Monte-Carlo.Pour pouvoir passer aux prototypes et aux applications réelles, les résultats nécessitent une validation expérimentale. Par conséquent, nous présentons également une méthode rapide et efficace pour l'extraction à distance des coefficients de réflexion de puissance sur une structure multicouche modélisant un déversement d'hydrocarbures à la surface de l'eau de mer. Les résultats expérimentaux obtenus sont analysés et comparés à des calculs théoriques. / Oil spill in sea water is one of the main accidents that adversely affect the maritime environment for a long period of time. It is crucial to have oil spill detecting and monitoring systems to have quick intervention to contain the danger. Such systems use several techniques and sensors, where most recent ones are those done remotely using satellite and airborne systems. The European Maritime Safety Agency (EMSA) launched in 2016 the need to use a complementary system, using drones, to the present satellite maritime surveillance systems.In our work, we propose the use of the drones for oil spill detection system. The drone-based radar will allow quick assessment and real time data processing of the area where the flag of possible spills is raised by witnesses. Parallelization in scanning can be used to cover large area in a critical time. Furthermore, scanning with drones provides high spatial resolution compared to satellite and with a principal advantage of relative low cost compared to dedicated airborne detection systems. Drones can be designated as nadir-looking systems (transmit and receive at zero angle from the normal). Being largely independent of surface roughness, the returns from nadir (or near-nadir) systems will benefit from the dominance of the specular scattering and allow detection even in very low wind conditions. The same conditions are considered to be unsuitable for detection using other recent techniques.In this thesis, we present a new probabilistic approach which uses nadir-looking wide-band radar for oil spill detection applications. The proposed approach combines a single layer scattering model with Bayesian statistics in order to evaluate the probability of detection of oil slicks, within a plausible range of thicknesses, on seawater. We present a framework of algorithms that utilize measurements of the reflectivity value to detect oil spills. The framework supports one or more measurements collected at single or multiple frequencies in the C-band and X-band. Performance analysis of all three types of detectors (single, dual- and tri-frequency) is done. The analysis for the results obtained from both flat- and rough- surfaces interface is also presented.We complement the detection-algorithms by a new approach targeting the estimation of the oil slick thickness. We present Maximum Likelihood single-, dual- and multi-frequency estimators. The latter use Minimum-Euclidean distance algorithm, in pre-defined 1-D, 2-D or K-D constellation sets, on simulated reflectivities to estimate the thickness of the oil slick. The derived algorithms are presented and tested using Monte-Carlo simulation.To be able to move forward to prototypes and real applications, the results need experimental validation. Therefore, we also present a fast and efficient method for the remote extraction of the power reflection coefficients on multilayer structure modeling an oil spill on the top surface of sea water. Experimental results obtained are analyzed and compared to theoretical calculations.

Thesis (M.S. in System Engineering in Electronic Warfare)--Naval Postgraduate School, September 1990. / Thesis Advisor(s): Atwater, H.A. Second Reader: Janaswamy, R. "September 1990." Description based on title screen as viewed on December 29, 2009. DTIC Identifier(s): Radar absorbing materials, radar cross sections, radiation absorbers, lossy dielectrics. Author(s) subject terms: Wave absorber, dielectric material. Includes bibliographical references (p. 55-56). Also available in print.