The effects of wind farm installation on the conventional monostatic radar operation have been investigated in previous studies. The interference on radar operation is due to the complex scattering characteristics from the wind turbine structure. This research considers alternative approach for studying and potentially mitigating these negative impacts by adapting the multistatic radar system technique. This radar principle is well known and it is attracting research interest recently, but has not been applied in modelling the wind farm interference on multistatic radar detection and tracking of multiple targets. The research proposes two areas of novelties. The first area includes the simulation tool development of multistatic radar operation near a wind farm environment. The second area includes the adaptation of Range-Only target detection approach based on mathematical and/or statistical methods for target detection and tracking, such as Interval Analysis and Particle Filter. These methods have not been applied against such complex detection scenario of large number of targets within a wind farm environment. Range-Only target detection approach is often considered to achieve flexibility in design and reduction in cost and complexity of the radar system. However, this approach may require advanced signal processing techniques to effectively associate measurements from multiple sensors to estimate targets positions. This issue proved to be more challenging for the complex detection environment of a wind farm due to the increase in number of measurements from the complex radar scattering of each turbine. The research conducts a comparison between Interval Analysis and Particle Filter. The comparison is based on the performance of the two methods according to three aspects; number of real targets detected, number of ghost targets detected and the accuracy of the estimated detections. Different detection scenarios are considered for this comparison, such as single target detection, wind farm detection, and ultimately multiple targets at various elevations within a wind farm environment.

<P> For over six decades, the theory and design of radar systems have been dominated by probability theory and statistics, information theory, signal processing and control. However, the similar encoding-decoding property that exists between the visual brain and radar has been sadly overlooked in all radar systems. This thesis lays down the foundation of a new generation of radar systems, namely cognitive radar, that was described in a 2006 seminal paper by Haykin. Four essential elements of cognitive radar are Bayesian filtering in the receiver, dynamic programming in the transmitter, memory, and global feedback to facilitate computational intelligence. All these elements excluding the memory compose a well known property of mammalian cortex, the perception-action cycle. As such, the cognitive radar that has only this cycle is named as the basic cognitive radar (BCR). For t racking applications, t his thesis presents the underlying theory of BCR, with emphasis being placed on the cubature Kalman filter to approximate the Bayesian filter in the receiver, dynamic optimization for transmit-waveform selection in the transmitter, and global feedback embodying the transmitter , the radar environment, and the receiver all under one overall feedback loop. </p> <p> Built on the knowledge learnt from the BCR, this thesis expands the basic perception-action cycle to encompass three more properties of human cognition , that is, memory, attention, and intelligence. Specifically, the provision for memory includes the three essential elements, i. e. , the perceptual memory, executive memory, and coordinating perception-action memory that couples the first two memories. Provision of the three memories adds an advanced version of cognitive radar, namely the nested cognitive radar (NCR) in light of the nesting of three memories in the perception-action cycle. </p> <p> In this thesis, extensive computer simulations are also conducted to demonstrate the ability of this new radar concept over a conventional radar structure. Three important scenarios of tracking applications are considered, they are (a), linear target tracking; (b), falling object tracking; and (c), high-dimensional target tracking with continuous-discrete model. All simulation results confirm that cognitive radar outperforms the conventional radar systems significantly. </p> <p> In conducting the simulations, an interesting phenomenon is also observed, which is named the chattering effect. The underlying physics and mathematical model of this effect are discussed. For the purpose of studying the behaviour of cognitive radar in disturbance, demonstrative experiments are further conducted. Simulation results indicate the superiority of NCR over BCR and t he conventional radar in low, moderate and even strong disturbance. </p> / Thesis / Doctor of Philosophy (PhD)

Modern radar systems must operate in a wide variety of time-varying conditions. These include various types of interference from neighboring systems, self-interference or clutter, and targets with fluctuating responses. It has been well-established that the quality and nature of radar measurements depend heavily on the choice of signal transmitted by the radar. In this dissertation, we discuss techniques which may be used to adapt the radar's waveform on-the-fly while making very few a priori assumptions about the physical environment. By employing tools from reinforcement learning and online learning, we present a variety of algorithms which handle practical issues of the waveform selection problem that have been left open by previous works. In general, we focus on two key challenges inherent to the waveform selection problem, sample-efficiency and universality. Sample-efficiency corresponds to the number of experiences a learning algorithm requires to achieve desirable performance. Universality refers to the learning algorithm's ability to achieve desirable performance across a wide range of physical environments. Specifically, we develop a contextual bandit-based approach to vastly improve the sample-efficiency of learning compared to previous works. We then improve the generalization performance of this model by developing a Bayesian meta-learning technique. To handle the problem of universality, we develop a learning algorithm which is asymptotically optimal in any Markov environment having finite memory length. Finally, we compare the performance of learning-based waveform selection to fixed rule-based waveform selection strategies for the scenarios of dynamic spectrum access and multiple-target tracking. We draw conclusions as to when learning-based approaches are expected to significantly outperform rule-based strategies, as well as the converse. / Doctor of Philosophy / Modern radar systems must operate in a wide variety of time-varying conditions. These include various types of interference from neighboring systems, self-interference or clutter, and targets with fluctuating responses. It has been well-established that the quality and nature of radar measurements depend heavily on the choice of signal transmitted by the radar. In this dissertation, we discuss techniques which may be used to adapt the radar's waveform on-the-fly while making very few explicit assumptions about the physical environment. By employing tools from reinforcement learning and online learning, we present a variety of algorithms which handle practical and theoretical issues of the waveform selection problem that have been left open by previous works. We begin by asking the questions "What is cognitive radar?" and "When should cognitive radar be used?" in order to develop a broad mathematical framework for the signal selection problem. The latter chapters then deal with the role of intelligent real-time decision-making algorithms which select favorable signals for target tracking and interference mitigation. We conclude by discussing the possible roles of cognitive radar within future wireless networks and larger autonomous systems.

The United States Federal Communications Commission (FCC) in its recent report and order has prescribed the creation of Citizens Broadband Radio Service (CRBS) in the 3.5 GHz band to enable sharing between wireless broadband devices and incumbent radar systems. This sharing will be enabled by use of geolocation database with supporting infrastructure termed as Spectrum Access System (SAS). Although using SAS for spectrum sharing has many pragmatic advantages, it also raises potentially serious operational security (OPSEC) issues. In this thesis, we explore OPSEC, location privacy in particular, of incumbent radars in the 3.5 GHz band. First, we show that adversarial secondary users can easily infer the locations of incumbent radars by making seemingly innocuous queries to the database. Then, we propose several obfuscation techniques that can be implemented by the SAS for countering such inference attacks. We also investigate obfuscation techniques' efficacy in minimizing spectral efficiency loss while preserving incumbent privacy. Recently, the 3GPP Rel.13 has specified a new standard to provide wide-area connectivity for IoT, termed as Narrowband IoT (NB-IoT). NB-IoT achieves excellent coexistence with legacy mobile standards, and can be deployed in any of the 2G/3G/4G spectrum (450 MHz to 3.5 GHz). Recent industry efforts show deployment of IoT networks in unlicensed spectrum, including shared bands (e.g., 3.5 GHz band). However, operating NB-IoT systems in the 3.5 GHz band can result in significant BLER and coverage loss. In this thesis, we analyse results from extensive experimental studies on the coexistence of NB-IoT and radar systems, and demonstrate the coverage loss of NB-IoT in shared spectrum. / Master of Science

Cruise missile mission planning is a key activity of cruise missile operations. Ground planning activities aim at low observable missions that have high probability of success. These activities include end game planning, route planning and launch planning. While end game planning tries to optimize end game parameters for maximum effectiveness, route planning tries to maximize survivability and enable navigational supports by determining the waypoints to from launch zone to target through a defended area. And lastly, planner tries to find the appropriate launch parameters that will prohibit platform to contact enemy agents. Mission rehearsal is the execution of the planned mission in a virtual environment that will be constructed with the data that drives the planning process. Mission rehearsal will support planners by providing possible results of the planned mission. Stochastic processes of the execution of the planned mission will be incorporated in the simulation of the combat. Along with platform, cruise missile and target, other players like SAM Sites or Search Radars (Early Warning Radars) will be incorporated in the rehearsal process.

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 83-86). Also available in electronic format on the Internet.

Three novel approaches that are based on a recent communication technique called time compression overlap-add (TC-OLA), are introduced into pulse compression (PC) radar systems to improve the radar waveform shaping and enhance radar performance. The first approach lays down a powerful framework for combining the TC-OLA technique into traditional PC radar system. The new TC-OLA-based radar obtained is compared with other radars, namely traditional linear frequency modulation (LFM), and wideband LFM which has the same processing gain under different background situations. The results show the superiority of the proposed radar over the others. The second approach combines a random phase noise signal with a selected radar signal to build a new radar system, SSLFM radar, that enjoys the low-probability of intercept property, and, therefore, has higher immunity against noise jamming techniques compared with other radar systems. The properly recovery of the transmitted signal, however, requires a synchronization system at the receiver side. In this dissertation, we propose three synchronization systems each having different pros and cons. The last approach takes the radar waveform design methodology in a different direction and proposes a novel framework to combine any number of radar signal and transmit them simultaneously. Instead of trying to achieve universality through waveform shaping optimization, we do so via pluralism. As a proof of concept, all the proposed radars have been implemented and tested on software-defined radar (SDR). The theoretical and the experimental results showed the superiority of all proposed radar systems. Since TC-OLA is fundamental to this work, we add a chapter to propose a new technique called downsample upsample shift add (DUSA) to address the limitations of the existing implementation of TC-OLA. / Graduate

Thesis (PhD (Electrical and Electronic Engineering)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: A monostatic baseband radar is required with the capability of detecting close range targets that appear at distances comparable to the system’s resolution, without compromising the radar’s maximum range. The application in borehole radar imposes further constraints associated with the physical limitations and variable electromagnetic environment of different borehole diameters and conditions. This dissertation discusses the complete design process of the analog section of a monostatic radar that successfully addresses these issues. The proposed transceiver employs a series duplexing arrangement consisting of an antenna, transmitter, receiver and an isolation switch. An exponentially decaying tail is observed in the current flowing on a borehole radar antenna when excited by pulse waveforms. The characteristics of this tail depend strongly on the borehole environment. A measurement technique is developed that accurately quantifies this exponential decay by digitizing a logarithmic representation of the antenna current while it is operating in various boreholes. Transmitters are then designed to drive these antennas with waveforms that prevent the formation of current tails. This is achieved through the use of pole-zero networks or alternatively by generating certain asymmetric, bipolar waveforms. The transmitters are simultaneously designed to have an output impedance approximating a short circuit after the transient is generated. In the series configuration proposed here, the duplexing of the antenna between transmitter and receiver is then reduced to simply isolating the receiver during transmit-mode. The switch responsible for this isolation disconnects the receiver and presents a short circuit between antenna and transmitter during transmit-mode, while connecting the receiver terminals between the antenna and the short circuited transmitter terminals in receive-mode. The required close-in performance of the transceiver dictates that the transition between these two states of the isolation switch occur in a time similar to the duration of the transmitter waveform. The switching artefacts generated by the switch are consequently similar to the radar data signal. The isolation switch employs an innovative configuration (using both transistors and diodes) which accepts a single control signal and causes the switching artefacts to be generated as a common mode signal, while a differential path is created for the radar data signal which is being switched. This leads to effective suppression of the switching signal in the signal passed to the receiver. Dissipative filtering is advocated as a fundamental design principle for high fidelity receivers and it is shown how it can be applied by using constant impedance equalizers and diplexers as basic building blocks. This principle is used as the basis for the design of this transceiver's receivers, which incorporate both standard gain blocks and operational amplifiers. A complete borehole radar system, based on the transceiver developed here, was built and tested; resulting in the first known practical monostatic borehole radar system. Data obtained in field trials are presented and suggest that the monostatic system compares well with current state of the art bi-static systems. / AFRIKAANSE OPSOMMING: Die behoefte is geïdentifiseer vir 'n monostatiese basisbandradar wat oor die vermoë beskik om nabygeleë teikens op 'n afstand soortgelyk aan die resolusie van die stelsel waar te neem, sonder om die maksimum bereik van die stelsel in te kort. Die toepassing daarvan in 'n boorgatradarstelsel lei tot verdere vereistes vanweë die fisiese beperkings en veranderende elektromagnetiese omgewing van boorgate met verskillende deursnitte en toestande. Hierdie proefskrif is gemoeid met die volledige ontwerpsprosedure van die analoog gedeelte van 'n monostatiese radar wat al hierdie kwessies aanspreek. 'n Serie verbinding van antenne, sender, ontvanger en isolasieskakelaar word ingespan vir hierdie ontwerp. Eksponensieel wegsterwende stertjies word waargeneem in die antennestroom van 'n boorgatradarantenne wanneer dit aangedryf word deur puls golfvorms. 'n Meettegniek word ontwikkel wat hierdie eksponensiële verslapping noukeurig kan monitor deur 'n logaritmiese voorstelling van die antennastroom te versyfer terwyl dit ontplooi word in verskillende boorgate. Senders word dan ontwikkel om hierdie antennes aan te dryf met golfvorms wat juis die vorming van hierdie stertjies voorkom. Dit word bewerkstellig deur die gebruik van pool-zero netwerke of andersins deur die opwek van sekere asimmetriese, bipolêre golfvorms. Die senders se uittree-impedansies moet egter terselfdertyd ontwerp word om 'n kortsluiting te benader sodra die oorgang klaar opgewek is. Met die serie verbinding wat hier gebruik word, raak die vereiste tyddeling van die antenna tussen die sender en ontvanger dan bloot 'n geval van ontvanger-isolasie gedurende uitsaai-modus. Die skakelaar wat verantwoordelik is vir hierdie isolasie ontkoppel die ontvanger en vertoon soos 'n kortsluiting tussen sender en antenne tydens uitsaai-modus, maar verbind weer die terminale van die ontvanger tussen die antenne en kortgeslote senderterminale tydens ontvang-modus. Die vereiste kortafstand vermoë van die stelsel veroorsaak dat die tysduur van die oorgang tussen hierdie twee modusse soortgelyk is aan dié van die sender golfvorm en enige skakelverskynsels wat opgewek word deur die skakelaar is gevolglik soortgelyk aan die radardatasein self. Die isolasieskakelaar gebruik egter 'n innoverende konfigurasie (met transistors sowel as diodes) wat funksioneer met 'n enkele beheersein en die skakelverskynsels as gemene modus seine opwek, terwyl 'n differensiële seinpad geskep word vir die radardatasein wat geskakel word. Die skakelseine word gevolglik effektief onderdruk in die sein wat oorgedra word aan die ontvanger. Die gebruik van verkwistende filters word voorgestel as 'n fundamentele ontwerpsbeginsel vir hoëtrou ontvangers en daar word getoon hoe dit toegepas kan word met konstante impedansie vereffeningsbane en dipleksers. Hierdie beginsel is dan ook gebruik as basis vir die ontwerp van hierdie stelsel se ontvangers, wat gebruik maak van beide standard aanwinsblokke sowel as operasionel versterkers. 'n Volledige boorgatradarstelsel, gebaseer op die stelsel wat hier ontwikkel is, is gebou en getoets. Die gevolg is die eerste bekende, praktiese monostatiese boorgatradarstelsel. Data wat hiermee verwerf is word aangebied en dui daarop dat die monostatiese stelsel baie goed opweeg teen huidige bi-statiese stelsels.

No description available.

Med den nya omvärldsutvecklingen där NATO moderniserar sitt missilförsvar i Europa samt att Ryssland har placerat taktiska ballistiska robotar i Kaliningrad påverkade Sveriges behov till att anskaffa förmågan att bekämpa ballistiska robotar. Sverige har därför anskaffat Patriotsystemet, dock utan att tillföra ett radarsystem för att invisa ballistiska robotar till luftvärnsförbandet. Missilförsvar är ett väl utforskat område, allt från bekämpningsförlopp till hur en sensorkedja ska se ut. Forskningen tar däremot inte upp vilka förutsättningar ett nyanskaffat radarsystem behöver innefatta för att bidra till att invisa ballistiska robotar för luftvärnsförbanden. I uppsatsen genomfördes en modellering, teknisk analys, där teorin missilförsvar en kedja av event nyttjades för att härleda krav på radarprestanda. En analys om hur organisationerna idag nyttjar radarsystem och hur de tekniska och taktiska kraven påverkar organisationen genomfördes med konceptet militär nytta. Resultatet visar att organisationen där radarsystemet tillförs behövde kompletteras med ett sensorkompani och säkerhetsförband för att uppfylla kravet till invisning. Mot bakgrunden av det scenario som togs fram för undersökning visar den tekniska analysen att radarn vara fordonsburen samt ha en räckvidd på 500 km och en höjdtäckning på 50 km. Den måste även vara kompatibel med Patriotsystemet samt en sensorkedja för strategiskt partnerskap. / With the new developments in international affairs, where NATO modernizes its missile defense system in Europe and Russia has placed tactical ballistic missiles in Kaliningrad, Sweden needs to acquire the ability to combat ballistic missiles. Sweden has therefore acquired the Patriot system, however without adding an early warning radar for the Air defense against ballistic missile. Missile defense is a well-explored area, ranging from missile defense events to how a sensor chain should function. The research does not, however, discuss the abilities an acquired radar system needs to help guide ballistic missiles for Air defense units. In this essay, a modeling and a technical analysis based on the theory Missile defense a chain of events are used to conclude requirements for radar performance. An analysis of how the organizations use radar systems today and how the technical requirements affect the organizations was implemented with the concept Military utility. The result indicates the organization there the radar system will be implemented needs to be reinforced with a sensor company and a security unit to meet the requirement for guidance. The background of the scenario that has been developed for the analysis shows that the radar should be integrated to a vehicle, have a range of 500 kilometers and a height coverage of 50 kilometers. Battle management systems must also be compatible with the Patriot system and the sensor chain for strategic partnership.