385 research outputs found
Development of a Cost-Efficient Multi-Target Classification System Based on FMCW Radar for Security Gate Monitoring
Radar systems have a long history. Like many other great inventions, the origin of radar systems lies in warfare. Only in the last decade, radar systems have found widespread civil use in industrial measurement scenarios and automotive safety applications. Due to their resilience against harsh environments, they are used instead of or in addition to optical or ultrasonic systems. Radar sensors hold excellent capabilities to estimate distance and motion accurately, penetrate non-metallic objects, and remain unaffected by weather conditions. These capabilities make these devices extremely flexible in their applications. Electromagnetic waves centered at frequencies around 24 GHz offer high precision target measurements, compact antenna, and circuitry design, and lower atmospheric absorption than higher frequency-based systems.
This thesis studies non-cooperative automatic radar multi-target detection and classification. A prototype of a radar system with a new microwave-radar-based technique for short-range detection and classification of multiple human and vehicle targets passing through a road gate is presented. It allows identifying different types of targets, i.e., pedestrians, motorcycles, cars, and trucks. The developed system is based on a low-cost 24 GHz off-the-shelf FMCW radar, combined with an embedded Raspberry Pi PC for data acquisition and transmission to a remote processing PC, which takes care of detection and classification. This approach, which can find applications in both security and infrastructure surveillance, relies upon the processing of the scattered-field data acquired by the radar.
The developed method is based on an ad-hoc processing chain to accomplish the automatic target recognition task, which consists of blocks performing clutter and leakage removal with a frame subtraction technique, clustering with a DBSCAN approach, tracking algorithm based on the \u3b1-\u3b2 filter to follow the targets during traversal, features extraction, and finally classification of targets with a classification scheme based on support vector machines. The approach is validated in real experimental scenarios, showing its capabilities incorrectly detecting multiple targets belonging to different classes (i.e., pedestrians, cars, motorcycles, and trucks). The approach has been validated with experimental data acquired in different scenarios, showing good identification capabilities
Incorporating doppler velocity measurement for track initiation and maintenance
Performance of multiple target tracking algorithms in complex environments heavily relies on the success of track initiation and measurement-to-track association algorithms. Doppler velocity measurement is the major discriminant of clutter from the target of interest with relatively higher velocities. This work summarizes the analytical derivations and presents simulation results about track initiation and maintenance using Doppler velocity reports along with the 3D position measurements extracted by a phased array radar. Ā© The IEE
The application of digital techniques to an automatic radar track extraction system
'Modern' radar systems have come in for much criticism in recent years, particularly in the aftermath of the Falklands campaign. There have also been notable failures in commercial designs, including the well-publicised 'Nimrod' project which was abandoned due to persistent inability to meet signal processing requirements. There is clearly a need for improvement in radar signal processing techniques as many designs rely on technology dating from the late 1970's, much of which is obsolete by todayās standards. The Durham Radar Automatic Track Extraction System (RATES) is a practical implementation of current microprocessor technology, applied to plot extraction of surveillance radar data. In addition to suggestions for the design of such a system, results are quoted for the predicted performance when compared with a similar product using 1970's design methodology. Suggestions are given for the use of other VLSI techniques in plot extraction, including logic arrays and digital signal processors. In conclusion, there is an illustrated discussion concerning the use of systolic arrays in RATES and a prediction that this will represent the optimum architecture for future high-speed radar signal processors
Radar Technology
In this book āRadar Technologyā, the chapters are divided into four main topic areas: Topic area 1: āRadar Systemsā consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: āRadar Applicationsā shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: āRadar Functional Chain and Signal Processingā describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: āRadar Subsystems and Componentsā consists of design technology of radar subsystem components like antenna design or waveform design
Frequency diversity wideband digital receiver and signal processor for solid-state dual-polarimetric weather radars
2012 Summer.Includes bibliographical references.The recent spate in the use of solid-state transmitters for weather radar systems has unexceptionably revolutionized the research in meteorology. The solid-state transmitters allow transmission of low peak powers without losing the radar range resolution by allowing the use of pulse compression waveforms. In this research, a novel frequency-diversity wideband waveform is proposed and realized to extenuate the low sensitivity of solid-state radars and mitigate the blind range problem tied with the longer pulse compression waveforms. The latest developments in the computing landscape have permitted the design of wideband digital receivers which can process this novel waveform on Field Programmable Gate Array (FPGA) chips. In terms of signal processing, wideband systems are generally characterized by the fact that the bandwidth of the signal of interest is comparable to the sampled bandwidth; that is, a band of frequencies must be selected and filtered out from a comparable spectral window in which the signal might occur. The development of such a wideband digital receiver opens a window for exciting research opportunities for improved estimation of precipitation measurements for higher frequency systems such as X, Ku and Ka bands, satellite-borne radars and other solid-state ground-based radars. This research describes various unique challenges associated with the design of a multi-channel wideband receiver. The receiver consists of twelve channels which simultaneously downconvert and filter the digitized intermediate-frequency (IF) signal for radar data processing. The product processing for the multi-channel digital receiver mandates a software and network architecture which provides for generating and archiving a single meteorological product profile culled from multi-pulse profiles at an increased data date. The multi-channel digital receiver also continuously samples the transmit pulse for calibration of radar receiver gain and transmit power. The multi-channel digital receiver has been successfully deployed as a key component in the recently developed National Aeronautical and Space Administration (NASA) Global Precipitation Measurement (GPM) Dual-Frequency Dual-Polarization Doppler Radar (D3R). The D3R is the principal ground validation instrument for the precipitation measurements of the Dual Precipitation Radar (DPR) onboard the GPM Core Observatory satellite scheduled for launch in 2014. The D3R system employs two broadly separated frequencies at Ku- and Ka-bands that together make measurements for precipitation types which need higher sensitivity such as light rain, drizzle and snow. This research describes unique design space to configure the digital receiver for D3R at several processing levels. At length, this research presents analysis and results obtained by employing the multi-carrier waveforms for D3R during the 2012 GPM Cold-Season Precipitation Experiment (GCPEx) campaign in Canada
Improvement of detection and tracking techniques in multistatic passive radar systems. (Mejora de tĆ©cnicas de detecciĆ³n y seguimiento en sistemas radar pasivos multiestĆ”ticos)
Esta tesis doctoral es el resultado de una intensa actividad investigadora centrada en los sensores radar pasivos para la mejora de las capacidades de detecciĆ³n y seguimiento en escenarios complejos con blancos terrestres y pequeƱos drones.
El trabajo de investigaciĆ³n se ha llevado a cabo en el grupo de investigaciĆ³n coordinado por la Dra. MarĆa Pilar Jarabo Amores, dentro del marco diferentes proyectos: IDEPAR (āImproved DEtection techniques for PAssive Radarsā), MASTERSAT (āMultichAnnel paSsive radar receiver exploiting TERrestrial and SATellite Illuminatorsā) y KRIPTON (āA Knowledge based appRoach to passIve radar detection using wideband sPace adapTive prOcessiNgā) financiados por el Ministerio de EconomĆa y Competitividad de EspaƱa; MAPIS (Multichannel passive ISAR imaging for military applications) y JAMPAR (āJAMmer-based PAssive Radarā), financiados por la Agencia Europea de Defensa (EDA) .
El objetivo principal es la mejora de las tĆ©cnicas de detecciĆ³n y seguimiento en radares pasivos con configuraciones biestĆ”ticas y multiestaticas. En el documento se desarrollan algoritmos para el aprovechamiento de seƱales procedentes de distintos iluminadores de oportunidad (transmisores DVB-T, satĆ©lites DVB-S y seƱales GPS). Las soluciones propuestas han sido integradas en el demostrador tecnolĆ³gico IDEPAR, desarrollado y actualizado bajo los proyectos mencionados, y validadas en escenarios reales declarados de interĆ©s por potenciales usuarios finales (Direccion general de armamento y material, instituto nacional de tecnologĆa aeroespacial y la armada espaƱola). Para el desarrollo y evaluaciĆ³n de cadenas de las cadenas de procesado, se plantean dos casos de estudio: blancos terrestres en escenarios semiurbanos edificios y pequeƱos blancos aĆ©reos en escenarios rurales y costeros. Las principales contribuciones se pueden resumir en los siguientes puntos:
ā¢ DiseƱo de tĆ©cnicas de seguimiento 2D en el espacio de trabajo rango biestĆ”tico-frecuencia Doppler: se desarrollan tĆ©cnicas de seguimiento para los dos casos de estudio, localizaciĆ³n de blancos terrestres y pequeƱos drones. Para es Ćŗltimo se implementan tĆ©cnicas capaces de seguir tanto el movimiento del dron como su firma Doppler, lo que permite implementar tĆ©cnicas de clasificaciĆ³n de blancos.
ā¢ DiseƱo de tĆ©cnicas de seguimiento de blancos capaces de integrar informaciĆ³n en el espacio 3D (rango, Doppler y acimut): se diseƱan tĆ©cnicas basadas en procesado en dos etapas, una primera con seguimiento en 2D para el filtrado de falsas alarmas y la segunda para el seguimiento en 3D y la conversiĆ³n de coordenadas a un plano local cartesiano. Se comparan soluciones basadas en filtros de Kalman para sistemas tanto lineales como no lineales.
ā¢ DiseƱo de cadenas de procesado para sistemas multiestĆ”ticos: la informaciĆ³n estimada del blanco sobre mĆŗltiples geometrĆas biestĆ”ticas es utilizada para incremento de las capacidades de localizaciĆ³n del blanco en el plano cartesiano local. Se presentan soluciones basadas en filtros de Kalman para sistemas no lineales explotando diferentes medidas biestĆ”ticas en el proceso de transformaciĆ³n de coordenadas, analizando las mejoras de precisiĆ³n en la localizaciĆ³n del blanco.
ā¢ DiseƱo de etapas de procesado para radares pasivos basados en seƱales satelitales de las constelaciones GPS DVB-S. Se estudian las caracterĆsticas de las seƱales satelitales identificando sus inconvenientes y proponiendo cadenas de procesado que permitan su utilizaciĆ³n para la detecciĆ³n y seguimiento de blancos terrestres.
ā¢ Estudio del uso de seƱales DVB-T multicanal con gaps de transmisiĆ³n entre los diferentes canales en sistemas radares pasivos. Con ello se incrementa la resoluciĆ³n del sistema, y las capacidades de detecciĆ³n, seguimiento y localizaciĆ³n. Se estudia el modelo de seƱal multicanal, sus efectos sobre el procesado coherente y se proponen cadenas de procesado para paliar los efectos adversos de este tipo de seƱales
Analytical evaluation of ILM sensors, volume 1
The functional requirements and operating environment constraints are defined for an independent landing monitor ILM which provides the flight crew with an independent assessment of the operation of the primary automatic landing system. The capabilities of radars, TV, forward looking infrared radiometers, multilateration, microwave radiometers, interferometers, and nuclear sensing concepts to meet the ILM conditions are analyzed. The most critical need for the ILM appears in the landing sequence from 1000 to 2000 meters from threshold through rollout. Of the sensing concepts analyzed, the following show potential of becoming feasible ILM's: redundant microwave landings systems, precision approach radar, airborne triangulation radar, multilateration with radar altimetry, and nuclear sensing
Target recognition techniques for multifunction phased array radar
This thesis, submitted for the degree of Doctor of Philosophy at University College London, is a
discussion and analysis of combined stepped-frequency and pulse-Doppler target recognition methods
which enable a multifunction phased array radar designed for automatic surveillance and multi-target
tracking to offer a Non Cooperative Target Recognition (NCTR) capability. The primary challenge
is to investigate the feasibility of NCTR via the use of high range resolution profiles. Given stepped
frequency waveforms effectively trade time for enhanced bandwidth, and thus resolution, attention is
paid to the design of a compromise between resolution and dwell time. A secondary challenge is to
investigate the additional benefits to overall target classification when the number of coherent pulses
within an NCTR wavefrom is expanded to enable the extraction of spectral features which can help
to differentiate particular classes of target. As with increased range resolution, the price for this extra
information is a further increase in dwell time. The response to the primary and secondary challenges
described above has involved the development of a number of novel techniques, which are summarized
below:
ā¢ Design and execution of a series of experiments to further the understanding of multifunction
phased array Radar NCTR techniques
ā¢ Development of a āHybridā stepped frequency technique which enables a significant extension
of range profiles without the proportional trade in resolution as experienced with āClassicalā
techniques
ā¢ Development of an āend to endā NCTR processing and visualization pipeline
ā¢ Use of āDoppler fractionā spectral features to enable aircraft target classification via propulsion
mechanism. Combination of Doppler fraction and physical length features to enable broad
aircraft type classification.
ā¢ Optimization of NCTR method classification performance as a function of feature and waveform
parameters.
ā¢ Generic waveform design tools to enable delivery of time costly NCTR waveforms within operational
constraints.
The thesis is largely based upon an analysis of experimental results obtained using the multifunction
phased array radar MESAR2, based at BAE Systems on the Isle of Wight. The NCTR
mode of MESAR2 consists of the transmission and reception of successive multi-pulse coherent bursts
upon each target being tracked. Each burst is stepped in frequency resulting in an overall bandwidth
sufficient to provide sub-metre range resolution. A sequence of experiments, (static trials, moving
point target trials and full aircraft trials) are described and an analysis of the robustness of target
length and Doppler spectra feature measurements from NCTR mode data recordings is presented. A
recorded data archive of 1498 NCTR looks upon 17 different trials aircraft using five different varieties
of stepped frequency waveform is used to determine classification performance as a function of
various signal processing parameters and extent (numbers of pulses) of the data used. From analysis
of the trials data, recommendations are made with regards to the design of an NCTR mode for an
operational system that uses stepped frequency techniques by design choice
Explorative Graph Visualization
Netzwerkstrukturen (Graphen) sind heutzutage weit verbreitet. Ihre Untersuchung dient dazu, ein besseres VerstƤndnis ihrer Struktur und der durch sie modellierten realen Aspekte zu gewinnen. Die Exploration solcher Netzwerke wird zumeist mit Visualisierungstechniken unterstĆ¼tzt. Ziel dieser Arbeit ist es, einen Ćberblick Ć¼ber die Probleme dieser Visualisierungen zu geben und konkrete LƶsungsansƤtze aufzuzeigen. Dabei werden neue Visualisierungstechniken eingefĆ¼hrt, um den Nutzen der gefĆ¼hrten Diskussion fĆ¼r die explorative Graphvisualisierung am konkreten Beispiel zu belegen.Network structures (graphs) have become a natural part of everyday life and their analysis helps to gain an understanding of their inherent structure and the real-world aspects thereby expressed. The exploration of graphs is largely supported and driven by visual means. The aim of this thesis is to give a comprehensive view on the problems associated with these visual means and to detail concrete solution approaches for them. Concrete visualization techniques are introduced to underline the value of this comprehensive discussion for supporting explorative graph visualization
Development of an infrared analyzer following the
A radar calibration subsystem for measuring the radar backscattering characteristics of an imaged terrain is described. To achieve the required accuracy for the backscattering coefficient measurement (about 2 dB with 80 percent confidence), the space hardware design includes a means of monitoring the state parameters of the radar. For example, the transmitter output power is sampled and a replica of its output waveform is circulated through the receiver. These are recorded digitally and are used on the ground to determine such radar parameters as the transmitter power and the receiver gain. This part of the data is needed by the ground processor to measure the terrain backscattering characteristics
- ā¦