Дисертації з теми "Local positioning systems"

In Local Positioning System I explored urban areas on foot and displayed the results of my explorations in the Dutzi gallery. My primary impetus for this project was to gain a more complete understanding of my surroundings. In a Global Positioning System (GPS)-driven re-imagining of British artist Richard Long's walks, I tracked my wanderings using a smartphone and filtered the resulting data and imagery through mechanical methods of production such as laser cutting and screen-printing. I then incorporated this imagery into a much larger installation piece that led viewers through a scale model of my exploration, via a detailed path on the wall and illuminated light boxes on the floor to guide their path.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
This project investigates the feasibility of position detection in an office or industrial setting. The objective is to design a low-cost positioning system that uses the unlicensed 5.7 GHz ISM band, with centimeter accuracy and limited range. During the conceptual design phase of the system, indoor channel models will be investigated to determine which of a variety of architectures will be useful. For triangulating the position, an array of widely spaced stationary receivers and a mobile transmitter is proposed.

This work presents a robust dual band local positioning system (LPS) working in the 2.4GHz and 5.8GHz industrial science medical (ISM) bands. Position measurement is based on the frequency-modulated continuous wave (FMCW) radar approach, which uses radio frequency (RF) chirp signals for propagation time and therefore distance measurements. Contrary to state of the art LPS, the presented system uses data from both bands to improve accuracy, precision and robustness. A complete system prototype is designed consisting of base stations and tags encapsulating most of the RF and analogue signal processing in custom integrated circuits. This design approach allows to reduce size and power consumption compared to a hybrid system using off-the-shelf components. Key components are implemented using concepts, which support operation in multiple frequency bands, namely, the receiver consisting of a low noise amplifier (LNA), mixer, frequency synthesizer with a wide band voltage-controlled oscillator (VCO) having broadband chirp generation capabilities and a dual band power amplifier. System imperfections occurring in FMCW radar systems are modelled. Effects neglected in literature such as compression, intermodulation, the influence of automatic gain control, blockers and spurious emissions are modeled. The results are used to derive a specification set for the circuit design. Position estimation from measured distances is done using an enhanced version of the grid search algorithm, which makes use of data from multiple frequency bands. The algorithm is designed to be easily and efficiently implemented in embedded systems. Measurements show a coverage range of the system of at least 245m. Ranging accuracy in an outdoor scenario can be as low as 8.2cm. Comparative dual band position measurements prove an effective outlier filtering in indoor and outdoor scenarios compared to single band results, yielding in a large gain of accuracy. Positioning accuracy in an indoor scenario with an area of 276m² can be improved from 1.27m at 2.4GHz and 1.86m at 5.8GHz to only 0.38m in the dual band case, corresponding to an improvement by at least a factor of 3.3. In a large outdoor scenario of 4.8 km², accuracy improves from 1.88m at 2.4GHz and 5.93m at 5.8GHz to 0.68m with dual band processing, which is a factor of at least 2.8
Die vorliegende Arbeit befasst sich mit dem Entwurf eines robusten lokalen Positionierungssystems (LPS), welches in den lizenzfreien Frequenzbereichen für industrielle, wissenschaftliche und medizinische Zwecke (industrial, scientific, medical, ISM) bei 2,4GHz und 5,8GHz arbeitet. Die Positionsbestimmung beruht auf dem Prinzip des frequenzmodulierten Dauerstrichradars (frequency modulated continuous wave, FMCW-Radar), welches hochfrequente Rampensignale für Laufzeitmessungen und damit Abstandsmessungen benutzt. Im Gegensatz zu aktuellen Arbeiten auf diesem Gebiet benutzt das vorgestellte System Daten aus beiden Frequenzbändern zur Erhöhung der Genauigkeit und Präzision sowie Verbesserung der Robustheit. Ein Prototyp des kompletten Systems bestehend aus Basisstationen und mobilen Stationen wurde entworfen. Fast die gesamte analoge hochfrequente Signalverarbeitungskette wurde als anwendungsspezifische integrierte Schaltung realisiert. Verglichen mit Systemen aus Standardkomponenten erlaubt dieser Ansatz die Miniaturisierung der Systemkomponenten und die Einsparung von Leistung. Schlüsselkomponenten wurden mit Konzepten für mehrbandige oder breitbandige Schaltungen entworfen. Dabei wurden Sender und Empfänger bestehend aus rauscharmem Verstärker, Mischer und Frequenzsynthesizer mit breitbandiger Frequenzrampenfunktion implementiert. Außerdem wurde ein Leistungsverstärker für die gleichzeitige Nutzung der beiden definierten Frequenzbänder entworfen. Um Spezifikationen für den Schaltungsentwurf zu erhalten, wurden in der Fachliteratur vernachlässigte Nichtidealitäten von FMCW-Radarsystemen modelliert. Dazu gehören Signalverzerrungen durch Kompression oder Intermodulation, der Einfluss der automatischen Verstärkungseinstellung sowie schmalbandige Störer und Nebenschwingungen. Die Ergebnisse der Modellierung wurden benutzt, um eine Spezifikation für den Schaltungsentwurf zu erhalten. Die Schätzung der Position aus gemessenen Abständen wurde über eine erweiterte Version des Gittersuchalgorithmus erreicht. Dieser nutzt die Abstandsmessdaten aus beiden Frequenzbändern. Der Algorithmus ist so entworfen, dass er effizient in einem eingebetteten System implementiert werden kann. Messungen zeigen eine maximale Reichweite des Systems von mindestens 245m. Die Genauigkeit von Abstandsmessungen im Freiland beträgt 8,2cm. Positionsmessungen wurden unter Verwendung beider Einzelbänder durchgeführt und mit den Ergebnissen des Zweiband-Gittersuchalgorithmus verglichen. Damit konnte eine starke Verbesserung der Positionsgenauigkeit erreicht werden. Die Genauigkeit in einem Innenraum mit einer Grundfläche von 276m² kann verbessert werden von 1,27m bei 2,4GHz und 1,86m bei 5,8GHz zu nur 0,38m im Zweibandverfahren. Das entspricht einer Verbesserung um einen Faktor von mindestens 3,3. In einem größeren Außenszenario mit einer Fläche von 4,8 km² verbessert sich die Genauigkeit um einen Faktor von mindestens 2,8 von 1,88m bei 2,4GHz und 5,93m bei 5,8GHz auf 0,68m bei Nutzung von Daten aus beiden Frequenzbändern

Målet med projektet var att med ultraljudsteknik tillverka en produktsom kan bestämma positionen i ett område på 10x10 m. För att uppnådetta tillverkades tre enheter kapabla att sända och mottagaultraljudssignaler. Enheterna består av en ultraljudstransceiver, ettkretskort som kan skicka utsignal och förstärka insignal samt ettwifi-kompatibelt microkontrollerkort. Två av dessa enheter användessom referenspunkter med kända koordinater. Koordinaterna för dentredje beräknades genom att med ultraljud mäta avstånden tillreferenspunkterna. Den slutgiltiga produkten var kapabel att mätapositionen i ett område på 2x2 m. Iakttagelser påvisar däremot att ettstörre område bör vara möjligt med samma uppställning.

Obtaining accurate and precise position information is critical in precision and autonomous agriculture. Systems accurate to the centimeter-level are available, but may be prohibitively expensive for relatively small farms and tasks that involve multiple vehicles. Optical resection is proposed as a potentially more cost-effective and scalable positioning system for such cases. The proposed system involves the placement of optical beacons at known locations throughout the environment and the use of cameras on the vehicle to detect the apparent angles between beacons. The position of the vehicle can be calculated with resection when three or four beacons are identified. In addition, the system provides precise orientation information, so a separate inertial measurement unit is not required. The system is seen as potentially cost-effective by taking advantage of the precision and low cost of digital image sensors. Whereas the components in other positioning systems tend to be more specialized, the widespread consumer demand for inexpensive and high quality cameras has allowed for billions of dollars of research and development to be spread across billions of image sensors.
Master of Science

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第22783号
農博第2426号
新制||農||1081(附属図書館)
学位論文||R2||N5303(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 近藤 直, 教授 飯田 訓久, 准教授 小川 雄一
学位規則第4条第1項該当

In the modern society, almost everyone has a smartphone. These devices tend to almost always use WiFi-networking. For the device to identify nearby WiFi access points it has to send out WiFi probing broadcasts. Nearby access points respond to these broadcasts in order to let the device know that they are within reach. This technique is called active scanning. This paper aims to answer if it is possible to use the signal strength of these broadcasts to localize the device transmitting them. We are interested in the possibility of creating this kind of system and the accuracy that it would be able to provide. This is a quantitative study where we produce our results based on experiments, measurements and observations. The experiments are set in a large square shaped area. A sensor was placed at each corner of the area that the smartphone will be tracked within. The smartphone will be sending WiFi probing broadcasts that will be monitored and measured by the sensors. The strength of the broadcast signal will be converted into the relative distance between the devices position and the sensors. These four distances, collected from each of the sensors, will further be converted into a position within the area by using trilateration. To measure the accuracy of the system, the true position of the device will be compared against the calculated position from the system using only the signal strength. Further, a deviation in the distance between the two locations will be calculated. The experiments resulted in a positioning system that was able to estimate positions within an 80 x 80m area. Fourteen location positions were taken which resulted in a mean deviation of 16.6 meters from the true location and a root mean squared error of 19.5 meters. We concluded that more readings within the same position gave a significant increase in accuracy, to the expense of time. Using single measurements would be more practical, but would not produce reliable positions. Keywords: WiFi, Probe Broadcast, Local Positioning System, Trilateration, RSSI.

Global Navigation Satellite Systems can provide position, velocity and time information to users using receiver hardware. The United States developed Global Positioning System (GPS) is the only current fully operational system; however further systems are in development. The GPS has shown considerable success for navigation, but it still has a number of problems that limit its accuracy. The two main problems are the ionosphere and local environment of the receiver. The ionosphere causes a delay and random rapid shifts in phase and amplitude (scintillation) to the signal. The local environment can provide the signal with multiple routes (multi-path) to the receiver. In this project a GPS signal simulator is developed, which models the effects of the ionosphere and multi-path on the modulated signals. The focus is made on the GPS system as the simulator measurements can be compared to the real measurements; however other systems will be considered in the future. A number of experiments investigating multi-path and ionospheric effects on a receiver’s ability to track the signals have been completed. The simulator has been used to replicate a real local multi-path environment and the results have been compared. Further investigations of the multi-path have shown a unique multi-path signature in the receiver power output. The later part of the thesis describes a case study investigating a short but rapid period of scintillation observed on three receivers based in Norway. An analysis of the multi-path environment was completed, but was found not to be the cause. The ionosphere was investigated using equipment based across Scandinavia. The equipment showed that geomagnetic conditions were disturbed at the time of the event. The GPS measurements were compared with all-sky camera data to show that the scintillation can be attributed to the GPS signal path crossing electron density structures associated with the aurora.

This research concerns the development of a smart sensory system for tracking a hand-held moving device to millimeter accuracy, for slow or nearly static applications over extended periods of time. Since different operators in different applications may use the system, the proposed design should provide the accurate position, orientation, and velocity of the object without relying on the knowledge of its operation and environment, and based purely on the motion that the object experiences. This thesis proposes the design of the integration a low-cost Local Positioning System (LPS) and a low-cost StrapDown Inertial Navigation System (SDINS) with the association of the modified EKF to determine 3D position and 3D orientation of a hand-held tool within a required accuracy. A hybrid LPS/SDINS combines and complements the best features of two different navigation systems, providing a unique solution to track and localize a moving object more precisely. SDINS provides continuous estimates of all components of a motion, but SDINS loses its accuracy over time because of inertial sensors drift and inherent noise. LPS has the advantage that it can possibly get absolute position and velocity independent of operation time; however, it is not highly robust, is computationally quite expensive, and exhibits low measurement rate. This research consists of three major parts: developing a multi-camera vision system as a reliable and cost-effective LPS, developing a SDINS for a hand-held tool, and developing a Kalman filter for sensor fusion. Developing the multi-camera vision system includes mounting the cameras around the workspace, calibrating the cameras, capturing images, applying image processing algorithms and features extraction for every single frame from each camera, and estimating the 3D position from 2D images. In this research, the specific configuration for setting up the multi-camera vision system is proposed to reduce the loss of line of sight as much as possible. The number of cameras, the position of the cameras with respect to each other, and the position and the orientation of the cameras with respect to the center of the world coordinate system are the crucial characteristics in this configuration. The proposed multi-camera vision system is implemented by employing four CCD cameras which are fixed in the navigation frame and their lenses placed on semicircle. All cameras are connected to a PC through the frame grabber, which includes four parallel video channels and is able to capture images from four cameras simultaneously. As a result of this arrangement, a wide circular field of view is initiated with less loss of line-of-sight. However, the calibration is more difficult than a monocular or stereo vision system. The calibration of the multi-camera vision system includes the precise camera modeling, single camera calibration for each camera, stereo camera calibration for each two neighboring cameras, defining a unique world coordinate system, and finding the transformation from each camera frame to the world coordinate system. Aside from the calibration procedure, digital image processing is required to be applied into the images captured by all four cameras in order to localize the tool tip. In this research, the digital image processing includes image enhancement, edge detection, boundary detection, and morphologic operations. After detecting the tool tip in each image captured by each camera, triangulation procedure and optimization algorithm are applied in order to find its 3D position with respect to the known navigation frame. In the SDINS, inertial sensors are mounted rigidly and directly to the body of the tracking object and the inertial measurements are transformed computationally to the known navigation frame. Usually, three gyros and three accelerometers, or a three-axis gyro and a three-axis accelerometer are used for implementing SDINS. The inertial sensors are typically integrated in an inertial measurement unit (IMU). IMUs commonly suffer from bias drift, scale-factor error owing to non-linearity and temperature changes, and misalignment as a result of minor manufacturing defects. Since all these errors lead to SDINS drift in position and orientation, a precise calibration procedure is required to compensate for these errors. The precision of the SDINS depends not only on the accuracy of calibration parameters but also on the common motion-dependent errors. The common motion-dependent errors refer to the errors caused by vibration, coning motion, sculling, and rotational motion. Since inertial sensors provide the full range of heading changes, turn rates, and applied forces that the object is experiencing along its movement, accurate 3D kinematics equations are developed to compensate for the common motion-dependent errors. Therefore, finding the complete knowledge of the motion and orientation of the tool tip requires significant computational complexity and challenges relating to resolution of specific forces, attitude computation, gravity compensation, and corrections for common motion-dependent errors. The Kalman filter technique is a powerful method for improving the output estimation and reducing the effect of the sensor drift. In this research, the modified EKF is proposed to reduce the error of position estimation. The proposed multi-camera vision system data with cooperation of the modified EKF assists the SDINS to deal with the drift problem. This configuration guarantees the real-time position and orientation tracking of the instrument. As a result of the proposed Kalman filter, the effect of the gravitational force in the state-space model will be removed and the error which results from inaccurate gravitational force is eliminated. In addition, the resulting position is smooth and ripple-free. The experimental results of the hybrid vision/SDINS design show that the position error of the tool tip in all directions is about one millimeter RMS. If the sampling rate of the vision system decreases from 20 fps to 5 fps, the errors are still acceptable for many applications.

Match-fixing is the process where the result of a sporting contest or game situation is deliberately manipulated for the personal material gain of one or more parties involved in that activity. Match-fixing is a serious problem in football affecting the integrity of the game. While indicators such as betting patterns have been used to identify match-fixing cases, there are still many that go undetected and even those that are exposed are difficult to prosecute due to a lack of hard evidence. Electronic performance and tracking systems can potentially assist in both identification and evidence- development actions by detecting unusual changes in a players’ movement behaviour on the pitch. The purpose of this research was to examine whether performance metrics derived from players' positional x and y coordinates can detect match-fixing behaviour in football. Six different performance metrics have been examined and were used to create player performance profiles. The player performance profiles have been compared with standardized mean differences and were analysed with Approximate entropy (ApEn) analysis and different recursive partitioning techniques. Results show that match-fixing behaviour influenced defensive fixing players’ performance metrics during a football game. Positional performance metrics were most associated with fixing behaviour and showed substantial differences compared to normal behaviour. Fixing players moved forward on the pitch and kept more distance towards the position-specific centroid. The altered movement pattern resulted in more spread of play in the lateral direction suggesting fixing players are stretching the defence to create space. Further studies should investigate the use of a wider range of fixing scenarios of numerous games to further develop the match-fixing detection framework. The findings of this thesis can be beneficial, not only for integrity purposes of the football related society, but also for a wider spectrum of team sports using electronic performance and tracking systems to measure player performance. These findings provide insights to player performance metrics underpinning match-fixing behaviour for defence players which can possibly assist in providing supporting evidence to prosecute match-fixing players. Further, it provides scientific knowledge to create a match-fixing detection approach which covers both betting and non-betting related match-fixing.

Player tracking data has previously been used to quantify movement profiles in the Australian Football League (AFL), however little research exists into its use to measure the spatial interactions of players. This thesis presents new methodologies for measuring the spatial interactions and occupancy of players in team sports. Global positioning systems (GPS) and local positioning systems (LPS) spatiotemporal datasets were sourced from training sessions, Under-18s matches and elite-level AFL matches. Datasets were consolidated with play-by-play transactions to infer ball position. An initial pilot study investigated the relative importance of traditional performance indicators to inform the focus of later studies. Subsequent chapters investigated the relative phase of inter- and intra-team player couples and multiple approaches to the measurement of the spatial control of individuals. Gaussian mixture models (GMM) were used to estimate the density of player groups in order to analyse changes in congestion throughout a match. Player motion models fit on player displacements were combined with a measure of field equity to value the passing decisions of players. A new approach to player motion models was developed by fitting the weighted distributions of player commitment to contest events. The resultant models more realistically explain player behaviour in proximity to the ball. The models were used to measure the spatial control of teams, from which the spatial characteristics of passes in the AFL were extracted. Passes were clustered into three distinct styles. In the final chapter of this thesis, the models developed in the preceding sections are used to develop a new decision-making model. The expected outcomes of a player’s passing options are modelled through consideration of field equity, spatial control, kicking variance and possession outcomes. Using this model, passing decisions from the 2017 and 2018 AFL seasons were analysed. In contrast to previous studies, the value of a player’s decision is measured relative to their options, rather than to an increase in possession expectation. This thesis aims to derive insights into player movement behaviour in Australian football. Furthermore, the novel spatial metrics developed in this thesis have applications in player recruitment, coaching, and performance analysis.