Using observations from the Global Positioning System (GPS) satellites to determine a three dimensional (3-D) geodetic control network are considered. The repeatability of individual baselines and 3-D vector closures are examined, in order to investigate refraction effects on GPS networks. The effect on GPS baselines of a height bias in the reference point's coordinates is also investigated. A least squares adjustment program is developed and used to obtain a single consistent set of 3-D coordinates for the Tygerberg Test Network (TTN). The results of two GPS processing packages are compared by means of a conformal transformation. It is concluded that single frequency measurements produce better results than the ionospheric free observable on short baselines. Furthermore, a standard atmospheric model shows an improvement over the Marini model to account for tropospheric refraction.

No description available.

Includes bibliographical references / Global Navigation Satellite Systems (GNSS) are used to provide information on position, time and velocity all over the world at any time of the day. Currently there are four operational GNSS and one of them is GPS (Global Positioning System) that is developed and maintained by U.S Department of Defence (DoD), which is widely used and accessible all over the world. The accuracy of the output or even the availability of the navigation system depends on current space weather conditions, which can cause random fluctuations of the phase and amplitude of the received signal, called scintillation. Interference of GNSS signals that are reflected and refracted from stationary objects on the ground, with signals that travel along a direct path via the ionosphere to the antenna, cause errors in the measured amplitude and phase. These errors are known as multipath errors and can lead to cycle slip and loss of lock on the satellite or degradation in the accuracy of position determination. High elevation cut off angles used for filtering GNSS signals, usually 15-30°, can reduce non-ionospheric interference due to multipath signals coming from the horizon. Since a fixed-elevation threshold does not take into consideration the surrounding physical environment of each GPS station, it can result in a significant loss of valuable data. Alternatively, if the fixed-elevation threshold is not high enough we run the risk of including multipath data in the analysis. In this project we characterized the multipath environment of the GPS Ionospheric Scintillation and TEC (Total Electron Content) Monitor (GISTM) receivers installed by SANSA (South African National Space Agency) at Gough Island (40:34oS and 9:88° W), Marion Island (46:87° S and 37:86° E), Hermanus (34:42° S and19:22° E) and SANAE IV (71:73° S and 2:2° W) by plotting azimuth-elevation maps of scintillation indices averaged over one year. The azimuth-elevation maps were used to identify objects that regularly scatter signals and cause high scintillation resulting from multipath effects. After identifying the multipath area from the azimuth-elevation map, an azimuth-dependent elevation threshold was developed using the MATLAB curve fitting tool. Using this method we are able to reduce the multi-path errors without losing important data. Using the azimuth-dependent elevation threshold typically gives 5 to 28% more useful data than using a 20° fixed-elevation threshold.

No description available.

No description available.

With the rapid development of wireless technologies, the demand for positioning services has grown dramatically over the past three decades. The Global Positioning System (GPS) is widely used in wireless devices for positioning purposes. However, in addition to having bulky and expensive equipment, GPS receivers do not operate properly in dense and indoor environments. Difficulties in using GPS lead us to use sensor localization in which the position information is obtained from the measurements collected within the network without the aid of external resources. Sensor localization has been a great topic of interest during past decades. Although many positioning algorithms have been developed previously in the literature, positioning is still a challenging task. There are many factors that can affect the positioning performance if they are neglected or not treated properly. These factors introduce many nuisance parameters which need to be either estimated or considered when the location is estimated. In this work, we exploit cooperative localization as a recent and trending technology and semidefinite programming (SDP) as a powerful tool in our research. Cooperative localization has several advantages over the traditional noncooperative localization in terms of positioning accuracy and localizability. Cooperation is also highly beneficial for networks with few anchor nodes and low communication range. On the other hand, SDP provides an alternative solution to the optimal maximum-likelihood (ML) estimation. Unlike in the ML estimator, convergence to the global minimum is guaranteed in SDP. It also has significantly lower complexity especially for cooperative networks in exchange for small performance degradation. Using these two concepts, four open problems within the area of cooperative localization and tracking in the presence of nuisance parameters are addressed. In particular, we focus on cooperative received signal strength-based localization when the propagation parameters including path-loss exponent and transmit powers are unknown. Cooperative time-of-arrival-based localization in harsh environments in the presence of severe non-line-of-sight (NLOS) propagation is also investigated. Cooperative localization in asynchronous networks is studied where the clock parameters are considered as nuisance parameters and the focus is on a joint synchronization and localization approach. Lastly, source tracking in NLOS environments is studied where source nodes are mobile and their status changes rapidly from LOS to NLOS and vice versa. / Ph. D.

GIS are geoprocessing programs that are commonly used to store and perform calculations on terrain data, maps, and other geospatial data. GIS offers the latest terrain and building data as well as tools to process this data. This thesis considers three applications of GIS data and software: a Large Scale Radio Frequency (RF) Model, a Medium Scale RF Model, and Indoor Positioning. The Large Scale RF Model estimates RF propagation using the latest terrain data supplied in GIS for frequencies ranging from 500 MHz to 5 GHz. The Medium Scale RF Model incorporates GIS building data to model WiFi systems at 2.4 GHz for a range of up to 300m. Both Models can be used by city planners and government offcials, who commonly use GIS for other geospatial and geostatistical information, to plan wireless broadband systems using GIS. An Indoor Positioning Experiment is also conducted to see if apriori knowledge of a building size, location, shape, and number of floors can aid in the RF geolocation of a target indoors. The experiment shows that correction of a target to within a building's boundaries reduces the location error of the target, and the vertical error is reduced by nearly half. / Master of Science

Dudonis, A., UAB „Prekybos miestelis URMAS“ pozicionavimo sprendimai [Rankraštis]: bakalauro baigiamasis darbas: vadyba ir verslo administravimas. Kaunas, ISM Vadybos ir ekonomikos universitetas, 2009. Temos aktualumas – įmonė keičiasi, modernėja, tampa vis šiuolaikiškesnė, tačiau požiūris į ją likęs kaip prieš dešimtį metų, o tai kenkia įmonės įvaizdžiui bei veiklai. Pagrindinis darbo tikslas – suformuluoti pozicionavimo teiginį, kurio pagrindu galėtų būti planuojamas bei vykdomas tolimesnis įmonės rinkodaros planas bei pati įmonės veikla. Šiam tikslui pasiekti iškelti šie uždaviniai: išanalizuoti didžiųjų prekybos centrų Lietuvoje rinką bei UAB “Prekybos miestelis URMAS“ vidinę situaciją ir identifikuoti probleminę sritį; atlikti empirinį tyrimą, po kurio paaiškėtų PM URMAS užimama pozicija vartotojų sąmonėje lyginant su kitais prekybos centrais; suformuoti pozicionavimo teiginį, kurio pagrindu būtų perpozicionuojamas URMAS. Darbą sudaro trys dalys: situacijos analizė, empirinis tyrimas ir vadybiniai sprendimai. Pirmoje darbo dalyje išanalizuota didžiųjų prekybos centrų Kauno mieste rinka, taip pat atlikta UAB „Prekybos miestelis URMAS“ vidinė analizė ir suformuluota pagrindinė darbo problema. Antroje darbo dalyje pateikti pagrindiniai empirinio tyrimo duomenys, kurie reikalingi pirmoje dalyje suformuluotai problemai įsisavinti bei sprendimui priimti. Trečioje darbo dalyje pateikiami vadybiniai sprendimai – konkretus pasiūlymas pagrindinei darbo problemai spręsti. Šiuo... [toliau žr. visą tekstą] / Dudonis, A., Positioning decisions of “Prekybos miestelis URMAS” [Manuscript]: final bachelor thesis: management and business administration. Kaunas, ISM University of Management and Economics, 2009. Relevance of the topic – the company is changing, become more and more modern, but its position in the minds of customers is like ten years ago. This affects the image and activities of the company in a negative way. Main aim of the thesis – to formulate the main positioning statement according to which further marketing plan could be planned and implemented. Tasks of the thesis: • To analyze the market of big supermarkets in Kaunas, to make an internal analysis of the URMAS enterprise and to identify the main problem; • To make and empirical research to identify current position of URMAS in the consumers‘ mind in comparison to other supermarkets; • To make the positioning statement according to which URMAS could be repositioned; In the process of writing bachelor thesis the empirical research was made to identify the current position of URMAS in the minds of consumers. The method was survey with standardized questionnaire. Gathered data was used in the managerial suggestions to maker URMAS’ positioning statement. The result of the thesis – the positioning statement was proposed according which further URMAS’ marketing plan should be made and implemented. Keywords: positioning, positioning statement, positioning process.

Olika navigeringstekniker är något som människan använder sig av dagligen. Det är och har varit en viktig del genom tiderna, i början handlade det om att kunna navigera till havs med hjälp av stjärnorna och idag har många människor i världen någon form av smarttelefon som kan användas som navigeringsverktyg. Inomhuspositionering är något som har blivit ett hett ämne den senaste tiden och eftersom GPS fungerar sämre inomhus har nya tekniker utvecklats för att navigera och positionera sig inomhus. De tekniker som ligger i framkant nu är bland annat Bluetooth Low Energy (BLE) och Wi-Fi där man med hjälp av triangulering kan positionera ut en användare inomhus. Frågan återstår då, vilket positioneringsverktyg är då lämpligt för inomhuspositionering. Detta examensarbete har utförts med en kombination av strategier. Som börjar med en jämförelsestudie av tre olika positioneringstekniker, BLE Wi-Fi och GPS, för att ta fram en lämplig positioneringsteknik för utvärdering i form av ett experiment där flera faktorer, främst precisionen, testas. I denna studie användes BLE beacons som positioneringsverktyg dels för att den var lätt att implementera men även för att den skulle uppnå hög precision. För att testa BLE beacon utvecklades en lätt applikationsprototyp som hade som huvudsyfte att kunna positionera ut en användare i ett koordinatsystem med hjälp av XYvärden. Genom att triangulering användes för att kunna positionera ut en användare uppnådde studien en medelmarginal på ungefär 76 centimeter när fem stycken beacons användes i ett område på 4 x 3 meter, vilket vi ansåg som godkänt för att kunna dra slutsatsen att BLE beacon är ett lämpligt verktyg när det kommer till en inomhuspositionering. Slutsatsen blev även att det skiljer sig avsevärt mycket i precision om man använder sig av för få eller helt enkelt dåligt placerade beacons. / Different navigation techniques are something that people uses on a daily basis. It has been and still is an important part in the history of mankind, initially navigation was about being able to navigate at sea using the stars, and today many people around the world have some kind of smartphone that can be used as a navigation tool. Indoor positioning is something that has become a hot topic in the last decade and since GPS has bad precision indoors new technologies has been developed to navigate and position objects indoors. Some leading technologies now includes Bluetooth Low Energy beacons and Wi-Fi, where you can position a user indoors using triangulation-techniques. The question still remains, which technique is viable for indoor positioning. This study has been conducted as a combination of two strategies, starting with a comparison study of three different positioning techniques, BLE, Wi-Fi and GPS, to come to a conclusion which positioning technique is suitable for indoor positioning. After the conclusion we evaluated the technique in the form of an experiment in which several factors, mainly the precision, are tested. In this study, BLE beacon were used as the positioning tool because it was easy to implement but also to able to achieve high precision in the right environment. To test the beacons, a light application prototype was developed that had the main purpose of positioning a user in a coordinate system using XY values. By using triangulation to position the user. The study achieved a mean margin of approximately 76 centimeters when five beacons were used in a 4 x 3 meter area. The conclusion was BLE beacons is a suitable tool when it comes to indoor positioning and that there is a lot of difference in precision when using too few or poorly placed beacons.

Positioning information for drones, machines, or other equipment has always been valuable. With fifth generation (5G) and long-term evolution (LTE) there are new possibilities to provide positioning information using the cellular network. When positioning information is available through the cellular network, having a standardized way of exposing positioning information would benefit a various number of applications. Thus, determining what requirements such an application programming interface (API) should have is important for future work. This thesis investigates and analyzes requirements that every API for exposing positioning information must have. It provides a theoretical reference API, the positioning exposure protocol (PEP), that fulfill all requirements. Additionally, the thesis analyzes available APIs on the market, and compares each and every one of them against the PEP, constructing a list of changes and extensions to make them compliant. The most compliant and suitable API is the gateway mobile location center (GMLC) API, which only requires a few changes and extensions to be functionally equivalent and fulfill allrequirements.