Data fusion for ground target tracking in GSM networks

Positioning in mobile cellular networks is an exciting research area. The Global System for Mobile communications (GSM) network, as a widely used mobile communication standard around the world, has shown the potential to provide position information. Ground target tracking is a significant application of finding the position of a mobile station (MS). However, a GSM positioning system based on current specifications faces many difficulties to yield an accurate position estimate. Since the signals are designed by communication needs rather than positioning, the resolution of the measurements in GSM networks for positioning is coarse. The ambiguities of the position estimate arise when there are not a sufficient number of measurements available. Moreover, due to the restriction of terrain, road and traffic, the ground target often maneuvers. Therefore, data fusion approaches, which integrate redundant information from different sources, are applied in this work to obtain improved position estimation accuracy. This work focuses on the state estimation problem of the MS\u27s position given the measurements from the GSM networks and a priori road information. A data fusion solution, which integrates time of arrival (TOA) and received signal strength (RSS) measurements using an extended Kalman filter (EKF), is proposed to provide an improved position estimate. The theoretical best achievable performance, posterior Cramer-Rao lower bound (PCRLB), is derived for the data fusion approach. The PCRLB is used to demonstrate the benefits of the fusion approach and applied as a benchmark to compare different estimators. The road constraint is incorporated into the estimation process as a pseudomeasurement. Simulations of the linear and nonlinear road segments prove the advantages of the road-constrained approach. Moreover, the motion mode uncertainty problem is considered and solved by a multiple model (MM) approach. In particular, an adaptive road-constrained interacting MM (ARC-IMM) estimator, which incorporates the road information into a variable structure MM mechanism, is proposed and demonstrated to be effective and robust to provide a significantly improved position estimate.Die Ortung in Mobilfunknetzen ist ein faszinierendes Forschungsgebiet. Der in großem Umfang genutzte Mobilfunkstandard für digitale Netze Global System for Mobile communications (GSM) kann auch zur Positionsbestimmung erfolgreich eingesetzt werden. Eine der bedeutenden Anwendungen bezüglich der Ortung von Mobilstationen (MS), d.h. von Mobilfunkend-geräten, ist das sogenannte Ground-Target-Tracking, also die Zielverfolgung derselben. Im Falle eines GSM-basierten Ortungssystems, das auf den aktuellen GSM-Spezifikationen basiert, müssen viele Schwierigkeiten überwunden werden, um die Position genau schätzen zu können. Zum einen liegen - da die Signale im Wesentlichen unter Berücksichtigung der Anforderungen hinsichtlich der Kommunikation (und nicht der Ortung) entworfen wurden - die Ergebnisse der Ortung in GSM-Netzwerken nur in einer groben Auflösung vor, und im Falle einer nicht ausreichend hohen Anzahl von verfügbaren Messwerten treten Mehrdeutigkeiten bei der Positionsschätzung auf. Zum anderen führt das Ziel entsprechend dem Gelände, dem Straßenverlauf und dem Verkehr oft Bewegungsänderungen durch. In dieser Arbeit werden deshalb Datenfusionsansätze verfolgt, die redundante Messwerte aus verschiedenen Quellen berücksichtigen, um eine verbesserte Genauigkeit der Positionsschätzung zu erzielen. Im Mittelpunkt der Arbeit steht die Zustandsschätzung unter Berücksichtigung der Messwerte aus dem GSM-Netzwerk und von a priori Information zum Straßenverlauf. Es wird ein Datenfusionsansatz eingeführt, mit dem die Fusion der Messwerte aus den Verfahren Time-of-Arrival (TOA) und Received-Signal-Strength (RSS) möglich wird, um einen verbesserten Positionsschätzwert zu erhalten. Es wird dabei ein Extended-Kalman-Filter (EKF) eingesetzt. Die theoretisch beste erzielbare Genauigkeit mit dem Datenfusionsansatz wird in Form der posterior Cramér-Rao lower bound (PCRLB) abgeleitet. Die PCRLB wird herangezogen um die Vorteile des Datenfusionsansatzes zu zeigen und dient als Benchmark für den Vergleich verschiedener Verfahren. Die Information über den Straßenverlauf wird in den Schätzprozess in Form einer Pseudomessung integriert. Simulationen sowohl in linearen als auch in nichtlinearen Fällen zeigen die Vorteile dieses Ansatzes, der die Randbedingungen durch den Straßenverlauf einbezieht. Weiterhin wird das Problem der Unsicherheit bei der Auswahl der Bewegungsart im Multiple-Model (MM) - Ansatz betrachtet und gelöst. Insbesondere wird ein sogenannter Adaptive-Road-Constraint-Interacting-Multiple-Model (ARC-IMM) - Schätzer, der die Straßen-information in einen MM-Ansatz mit variabler Struktur integriert, vorgeschlagen. Es wird gezeigt, dass dieser Schätzer effizient und robust ist, und eine wesentlich verbesserte Positionsschätzung liefert

The Interacting Multiple Models Algorithm with State-Dependent Value Assignment

The value of a state is a measure of its worth, so that, for example, waypoints have high value and regions inside of obstacles have very small value. We propose two methods of incorporating world information as state-dependent modifications to the interacting multiple models (IMM) algorithm, and then we use a game\u27s player-controlled trajectories as ground truths to compare the normal IMM algorithm to versions with our proposed modifications. The two methods involve modifying the model probabilities in the update step and modifying the transition probability matrix in the mixing step based on the assigned values of different target states. The state-dependent value assignment modifications are shown experimentally to perform better than the normal IMM algorithm in both estimating the target\u27s current state and predicting the target\u27s next state

The Interacting Multiple Models Algorithm with State-Dependent Value Assignment

The value of a state is a measure of its worth, so that, for example, waypoints have high value and regions inside of obstacles have very small value. We propose two methods of incorporating world information as state-dependent modifications to the interacting multiple models (IMM) algorithm, and then we use a game\u27s player-controlled trajectories as ground truths to compare the normal IMM algorithm to versions with our proposed modifications. The two methods involve modifying the model probabilities in the update step and modifying the transition probability matrix in the mixing step based on the assigned values of different target states. The state-dependent value assignment modifications are shown experimentally to perform better than the normal IMM algorithm in both estimating the target\u27s current state and predicting the target\u27s next state

Improvement of detection and tracking techniques in multistatic passive radar systems. (Mejora de técnicas de detección y seguimiento en sistemas radar pasivos multiestáticos)

Esta tesis doctoral es el resultado de una intensa actividad investigadora centrada en los sensores radar pasivos para la mejora de las capacidades de detección y seguimiento en escenarios complejos con blancos terrestres y pequeños drones. El trabajo de investigación se ha llevado a cabo en el grupo de investigación coordinado por la Dra. María Pilar Jarabo Amores, dentro del marco diferentes proyectos: IDEPAR (“Improved DEtection techniques for PAssive Radars”), MASTERSAT (“MultichAnnel paSsive radar receiver exploiting TERrestrial and SATellite Illuminators”) y KRIPTON (“A Knowledge based appRoach to passIve radar detection using wideband sPace adapTive prOcessiNg”) financiados por el Ministerio de Economía y Competitividad de España; MAPIS (Multichannel passive ISAR imaging for military applications) y JAMPAR (“JAMmer-based PAssive Radar”), financiados por la Agencia Europea de Defensa (EDA) . El objetivo principal es la mejora de las técnicas de detección y seguimiento en radares pasivos con configuraciones biestáticas y multiestaticas. En el documento se desarrollan algoritmos para el aprovechamiento de señales procedentes de distintos iluminadores de oportunidad (transmisores DVB-T, satélites DVB-S y señales GPS). Las soluciones propuestas han sido integradas en el demostrador tecnológico IDEPAR, desarrollado y actualizado bajo los proyectos mencionados, y validadas en escenarios reales declarados de interés por potenciales usuarios finales (Direccion general de armamento y material, instituto nacional de tecnología aeroespacial y la armada española). Para el desarrollo y evaluación de cadenas de las cadenas de procesado, se plantean dos casos de estudio: blancos terrestres en escenarios semiurbanos edificios y pequeños blancos aéreos en escenarios rurales y costeros. Las principales contribuciones se pueden resumir en los siguientes puntos: • Diseño de técnicas de seguimiento 2D en el espacio de trabajo rango biestático-frecuencia Doppler: se desarrollan técnicas de seguimiento para los dos casos de estudio, localización de blancos terrestres y pequeños drones. Para es último se implementan técnicas capaces de seguir tanto el movimiento del dron como su firma Doppler, lo que permite implementar técnicas de clasificación de blancos. • Diseño de técnicas de seguimiento de blancos capaces de integrar información en el espacio 3D (rango, Doppler y acimut): se diseñan técnicas 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 conversión de coordenadas a un plano local cartesiano. Se comparan soluciones basadas en filtros de Kalman para sistemas tanto lineales como no lineales. • Diseño de cadenas de procesado para sistemas multiestáticos: la información estimada del blanco sobre múltiples geometrías biestáticas es utilizada para incremento de las capacidades de localización del blanco en el plano cartesiano local. Se presentan soluciones basadas en filtros de Kalman para sistemas no lineales explotando diferentes medidas biestáticas en el proceso de transformación de coordenadas, analizando las mejoras de precisión en la localización del blanco. • Diseño de etapas de procesado para radares pasivos basados en señales satelitales de las constelaciones GPS DVB-S. Se estudian las características de las señales satelitales identificando sus inconvenientes y proponiendo cadenas de procesado que permitan su utilización para la detección y seguimiento de blancos terrestres. • Estudio del uso de señales DVB-T multicanal con gaps de transmisión entre los diferentes canales en sistemas radares pasivos. Con ello se incrementa la resolución del sistema, y las capacidades de detección, seguimiento y localización. Se estudia el modelo de señal multicanal, sus efectos sobre el procesado coherente y se proponen cadenas de procesado para paliar los efectos adversos de este tipo de señales

Wi-Fi based people tracking in challenging environments

People tracking is a key building block in many applications such as abnormal activity detection, gesture recognition, and elderly persons monitoring. Video-based systems have many limitations making them ineffective in many situations. Wi-Fi provides an easily accessible source of opportunity for people tracking that does not have the limitations of video-based systems. The system will detect, localise, and track people, based on the available Wi-Fi signals that are reflected from their bodies. Wi-Fi based systems still need to address some challenges in order to be able to operate in challenging environments. Some of these challenges include the detection of the weak signal, the detection of abrupt people motion, and the presence of multipath propagation. In this thesis, these three main challenges will be addressed. Firstly, a weak signal detection method that uses the changes in the signals that are reflected from static objects, to improve the detection probability of weak signals that are reflected from the person’s body. Then, a deep learning based Wi-Fi localisation technique is proposed that significantly improves the runtime and the accuracy in comparison with existing techniques. After that, a quantum mechanics inspired tracking method is proposed to address the abrupt motion problem. The proposed method uses some interesting phenomena in the quantum world, where the person is allowed to exist at multiple positions simultaneously. The results show a significant improvement in reducing the tracking error and in reducing the tracking delay

Implementation of tracking algorithms for multistatic systems

Due to the increased prevalence of ubiquitous communication technologies and the reduced cost of electronic components, there is an increasing interest in developing networked radar systems. Such networked radar systems offer potential benefits in robustness as well as improvements in performance for detection, tracking and classification. As a branch of applied computer sciences sensor data fusion addresses the ability to process this vast quantity of information, generated by multiple sources, in an effective way. The purpose of this thesis is to validate the tracking algorithms implemented, to determine whether they are capable of identifying and tracking two closely spaced targets, to determine the capability of the system to track a target that moves with fast maneuvers as well as the ability to handle a potential simultaneous attack from both the air and the sea. We present a method for multiple target tracking using multiple sensors both for passive and active sensors. Firstly, regarding active radar, we describe an algorithm for combining range-Doppler data from multiple sensors to perform multi-target tracking. In particular we considered the problem of very poor azimuth resolution. In this case more than two sensors are needed to triangulate target tracks and techniques like multilateration are needed to overcome the problem. Then two tracking algorithms for bistatic DVB-T passive radar based on the Extended Kalman Filter (for single target tracking) and on the Kalman filter (for multiple target tracking), exploiting measurement of bistatic range and bistatic velocity of a target are described. Also the direction of arrival of the target is estimated through beamforming and then used in the tracking model. The algorithms have been tested and validated by using real data

Mechatronic Systems

Mechatronics, the synergistic blend of mechanics, electronics, and computer science, has evolved over the past twenty five years, leading to a novel stage of engineering design. By integrating the best design practices with the most advanced technologies, mechatronics aims at realizing high-quality products, guaranteeing at the same time a substantial reduction of time and costs of manufacturing. Mechatronic systems are manifold and range from machine components, motion generators, and power producing machines to more complex devices, such as robotic systems and transportation vehicles. With its twenty chapters, which collect contributions from many researchers worldwide, this book provides an excellent survey of recent work in the field of mechatronics with applications in various fields, like robotics, medical and assistive technology, human-machine interaction, unmanned vehicles, manufacturing, and education. We would like to thank all the authors who have invested a great deal of time to write such interesting chapters, which we are sure will be valuable to the readers. Chapters 1 to 6 deal with applications of mechatronics for the development of robotic systems. Medical and assistive technologies and human-machine interaction systems are the topic of chapters 7 to 13.Chapters 14 and 15 concern mechatronic systems for autonomous vehicles. Chapters 16-19 deal with mechatronics in manufacturing contexts. Chapter 20 concludes the book, describing a method for the installation of mechatronics education in schools

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Interference Mitigation and Localization Based on Time-Frequency Analysis for Navigation Satellite Systems

Interference Mitigation and Localization Based on Time-Frequency Analysis for Navigation Satellite SystemsNowadays, the operation of global navigation satellite systems (GNSS) is imperative across a multitude of applications worldwide. The increasing reliance on accurate positioning and timing information has made more serious than ever the consequences of possible service outages in the satellite navigation systems. Among others, interference is regarded as the primary threat to their operation. Due the recent proliferation of portable interferers, notably jammers, it has now become common for GNSS receivers to endure simultaneous attacks from multiple sources of interference, which are likely spatially distributed and transmit different modulations. To the best knowledge of the author, the present dissertation is the first publication to investigate the use of the S-transform (ST) to devise countermeasures to interference. The original contributions in this context are mainly: • the formulation of a complexity-scalable ST implementable in real time as a bank of filters; • a method for characterizing and localizing multiple in-car jammers through interference snapshots that are collected by separate receivers and analysed with a clever use of the ST; • a preliminary assessment of novel methods for mitigating generic interference at the receiver end by means the ST and more computationally efficient variants of the transform. Besides GNSSs, the countermeasures to interference proposed are equivalently applicable to protect any direct-sequence spread spectrum (DS-SS) communication