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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Efficient differential code bias and ionosphere modeling and their impact on the network-based GPS positioning

Hong, Chang-Ki, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 197-204).
232

PTAG - aktiv RFID-tag med GPS

Bengtsson, Christofer, Madsen, Kristoffer January 2008 (has links)
<p>Free2Move AB is developing products for the market within wireless communication</p><p>and identification, among those active RFID-tags. The company had an idea about</p><p>providing one of their active RFID tags with a GPS receiver and transmit positions via</p><p>an existing RFID protocol. Desire from the company was also the possibility to log</p><p>positions and measure temperature. The finished prototype should also be able to be</p><p>activated by movement. The company had proposal about components that were to be</p><p>used in the project. A large part of the work was to understand how these worked and</p><p>how to combine them to fulfill the requirements established in agreement with</p><p>supervisor at Free2Move. A PIC microcontroller was used in the design of the prototype</p><p>and software implemented for communication with GPS, RFID tag and other</p><p>components. The result was a working prototype where an existing RFID tag was</p><p>integrated in the same printed circuit board layout as the GPS receiver and other</p><p>components that were used in the project.</p>
233

Kommunikationsalternativ för nätverks-RTK : <em>- virtuell referensstation kontra nätverksmeddelande</em>

Johansson, Daniel, Persson, Sören January 2008 (has links)
<p>Vid användning av nätverks-RTK behöver driftcentralen kommunicera med användarens GNSS-mottagare på ett effektivt sätt oberoende av fabrikat. Av den anledningen finns ett standardiserat format för överföring av data som är utvecklat av RTCM (The Radio Technical Commission for Maritime Services). 2006 publicerades version 3.1 som stödjer utsändning av s.k. nätverksmeddelande som innebär att komprimerade observationsdata skickas till mottagaren för beräkning av korrektioner. För att bestämma GNSS-mottagarens position används i dagsläget till största delen VRS-tekniken (Virtual Reference Station). Denna teknik används bland annat av SWEPOS som driver en nätverks-RTK-tjänst i Sverige. VRS-tekniken kräver att mottagarens position ska skickas till driftcentralen, där huvuddelen av beräkningarna sker. Nätverksmeddelande har inte funnits i tidigare versioner av RTCM-standarden, men införandet av dem innebär bland annat att korrektioner kan skickas med envägskommunikation och att större delen av beräkningarna kan göras i mottagaren.</p><p>Syftet med studien är att göra jämförelser mellan VRS och RTCM 3.1 nätverksmeddelande, med avseende på bland annat mätkvalitet och initialiseringstider. I studien ingick även att undersöka behovet av nätverksmeddelande och hur tekniken fungerar under förflyttning. I studien användes GNSS-mottagare från Leica och Trimble för att göra upprepade mätningar med dels VRS och dels RTCM 3.1 nätverksmeddelande med s.k. automatisk respektive statisk konfiguration. Statisk konfiguration användes i två olika nät, ett där SWEPOS-stationen Gävle och ett där SWEPOS-stationen Leksand användes som s.k. masterstation. Totalt 1200 mätningar utfördes på tre väl inmätta punkter under 12 dagar. Vid varje mätning registrerades tiden till fixlösning och mätt position. Resultaten bearbetades därefter och analyserades med statistiska metoder.</p><p>Resultaten visade bland annat att initialiseringstiden för nätverksmeddelande är något längre än för VRS och att det inte finns någon större skillnad i kvalitetstalen mellan VRS och nätverksmeddelande. Inte heller mellan det automatiska nätet och de statiska näten finns någon större skillnad. 95:e percentilens avvikelser var i plan 25 mm och i höjd 45 mm. De enda resultaten som skiljde sig nämnvärt från övriga var mätningarna med Leica i det statiska nätet med Leksand som masterstation, där Leica hade problem med att få fixlösning.</p> / <p>When using network RTK the control centre needs to communicate with the user's GNSS receivers in an efficient manner regardless of the brand of equipment. For this reason, a standardized format for transmission of data has been developed by RTCM (the Radio Technical Commission for Maritime Services). In 2006 the version 3.1 was released which supports broadcasting of network RTK messages which means that the compressed observation data are sent to the rover for calculation of corrections. Today the most used concept to determine the position of the rover is VRS (Virtual Reference Station). SWEPOS, which provides a network RTK service in Sweden, is based on the VRS concept. The concept requires that the position of the rover should be sent to the control centre, where most of the calculations are made. Network RTK messages have not been found in earlier versions of the RTCM standard, but their introduction means that corrections can be sent with one-way communication and that most of the calculations can be made in the rover.</p><p>The purpose of the study is to make comparisons between the VRS and RTCM 3.1 network RTK messages regarding the measurement quality and the time for initialization. The study also included to examine the need for network RTK messages and how the technology works while continuously moving the rover. The study used GNSS receivers from Leica and Trimble to make repeated measurements with VRS and with RTCM 3.1 with automatic and static configurations. Static configuration was used in two different networks, one in which the SWEPOS station Gävle and one in which the SWEPOS station Leksand was used as master station. Totally 1200 measurements were carried out on three known points in 12 days. At each measurement the time for initialization and the measured position was registered. The results were then processed and analysed using statistical methods.</p><p>The results showed that the times for initialization regarding network RTK messages are slightly longer than for VRS and that there is no obvious difference in quality between the VRS and network RTK messages. The difference between the automatic network and the static network is not noticeable either. 95th percentile discrepancies were 25 mm horizontally and 45 mm vertically. The only results that clearly differed from the rest of the measurements were those with Leica in the static network with Leksand as master station, where Leica had problems to resolve the ambiguities.</p>
234

Verkligheten som datorspelsmiljö

Sjöstrand, Peter, Bång, Lars January 2006 (has links)
<p>Syftet med arbetet är att undersöka huruvida det går det att utveckla ett spel som kan spelas både i verkligheten såväl som bakom en dator samtidigt. Hur kan ett spel som kombinerar virtuella och reella element utformas. Arbetet tar upp vilken teknik som kan användas samt hur en teknisk lösning kan se ut. All teknik som krävs för att realisera ett fungerande spel av denna typ finns tillgängligt och i detta arbete presenteras all bakgrund samt förarbete.</p>
235

Anpassning av befintligt stomnät för GPS-mätning i Åmåls kommun

Andersson, Maria, Klang, Anette, Gustafsson, Carina January 2004 (has links)
No description available.
236

Kan Nätverks-DGPS bidra till att effektivisera naturreservatsmätning? : en utvärdering av mätnoggrannhet och användaraspekter

Magni, Ida January 2007 (has links)
No description available.
237

Movement pattern of Moose (Alces alces) in southwestern Sweden in relation to highway traffic intensity

Henriksson, Lars-Henrik January 2007 (has links)
<p>Abstract</p><p>GPS telemetry is a method with good accuracy to determine animal movements in the terrain. It is necessary to determine locations of free-ranging animals in order to understand movement patterns and habitat use, and to understand the consequences of human impacts like highways. This study aims to describe moose movement patterns and to evaluate the effect of highway traffic intensity on moose movements across a highway.</p><p>Moose in Southwestern Sweden have different movement rates throughout the year. Increased movement rate for females was observed during spring and summer. The breeding season (15 September -15 October) is the most important season for bulls. Our result shows that bulls significantly increase their movement rate during the rut, compared to other times during the fall. Movement rate increased twice compared with female movement rate during this period. No difference was observed during the rutting period for females (15 September- 15 October) compared with no rutting period during fall. During winter time, both sexes retain low movements, mainly caused by energy saving actions. A distinct crepuscular rhythm was exhibited during the summer and fall season, movements were more intense during dawn and dusk hours. No distinct crepuscular rhythm was noticed during winter and spring seasons.</p><p>The traffic intensity at highway E6 in Southwestern Sweden increases during the morning hours and reaches its maximum during midday. Moose in southwestern Sweden crossed highway E6 more often at night time than day time. Thus highway crossings by moose occurred at times of peak moose movements, and traffic volume had lower importance.</p>
238

Motion and evolution of the Chaochou Fault, Southern Taiwan

Hassler, Lauren E. 01 November 2005 (has links)
The Chaochou Fault (CCF) is both an important lithologic boundary and a significant topographic feature in the Taiwan orogenic belt. It is the geologic boundary between the Slate Belt to the east, and the Western Foothills to the west. Although the fault is known to be a high angle oblique sinistral thrust fault in places, both its kinematic history and its current role in the development of the orogen are poorly understood. Field fabric data suggest that structural orientations vary along strike, particularly in the middle segment, the suspected location of the intersection of the on-land Eurasian continent-ocean boundary and the Luzon Island Arc. Foliation/solution cleavage is oriented NE-SW and in the northern and southern sections, but ESE-WNW in the middle segment. Slip lineations also reveal a change in fault motion from dip-parallel in the north to a more scattered pattern in the south. This correlates somewhat with recent GPS results, which indicate that the direction of current horizontal surface motion changes along strike from nearly perpendicular to the fault in the northern field area, to oblique and nearly parallel to the fault in the southern field area. The magnitude of vertical surface motion vectors, relative to Lanyu Island, decreases to the south. Surface morphology parameters, including mountain front sinuosity and valley floor width/valley height ratio indicate higher activity and uplift in the north. These observations correlate well with published apatite/zircon fission track data that indicate un-reset ages in the south, and reset ages in the northern segment. Geodetic and geomorphic data indicate that the northern segment of the CCF and Slate Belt are currently undergoing rapid uplift related to oblique arc-continent collision between the Eurasian continent and the Luzon arc. The southern segment is significantly less active perhaps because the orogen is not yet involved in direct arc-continent collision.
239

Logistic regression models for predicting trip reporting accuracy in GPS-enhanced household travel surveys

Forrest, Timothy Lee 25 April 2007 (has links)
This thesis presents a methodology for conducting logistic regression modeling of trip and household information obtained from household travel surveys and vehicle trip information obtained from global positioning systems (GPS) to better understand the trip underreporting that occurs. The methodology presented here builds on previous research by adding additional variables to the logistic regression model that might be significant in contributing to underreporting, specifically, trip purpose. Understanding the trip purpose is crucial in transportation planning because many of the transportation models used today are based on the number of trips in a given area by the purpose of a trip. The methodology used here was applied to two study areas in Texas, Laredo and Tyler-Longview. In these two study areas, household travel survey data and GPS-based vehicle tracking data was collected over a 24-hour period for 254 households and 388 vehicles. From these 254 households, a total of 2,795 trips were made, averaging 11.0 trips per household. By comparing the trips reported in the household travel survey with those recorded by the GPS unit, trips not reported in the household travel survey were identified. Logistic regression was shown to be effective in determining which household- and trip-related variables significantly contributed to the likelihood of a trip being reported. Although different variables were identified as significant in each of the models tested, one variable was found to be significant in all of them - trip purpose. It was also found that the household residence type and the use of household vehicles for commercial purposes did not significantly affect reporting rates in any of the models tested. The results shown here support the need for modeling trips by trip purpose, but also indicate that, from urban area to urban area, there are different factors contributing to the level of underreporting that occurs. An analysis of additional significant variables in each urban area found combinations that yielded trip reporting rates of 0%. Similar to the results of Zmud and Wolf (2003), trip duration and the number of vehicles available were also found to be significant in a full model encompassing both study areas.
240

Movement pattern of Moose (Alces alces) in southwestern Sweden in relation to highway traffic intensity

Henriksson, Lars-Henrik January 2007 (has links)
Abstract GPS telemetry is a method with good accuracy to determine animal movements in the terrain. It is necessary to determine locations of free-ranging animals in order to understand movement patterns and habitat use, and to understand the consequences of human impacts like highways. This study aims to describe moose movement patterns and to evaluate the effect of highway traffic intensity on moose movements across a highway. Moose in Southwestern Sweden have different movement rates throughout the year. Increased movement rate for females was observed during spring and summer. The breeding season (15 September -15 October) is the most important season for bulls. Our result shows that bulls significantly increase their movement rate during the rut, compared to other times during the fall. Movement rate increased twice compared with female movement rate during this period. No difference was observed during the rutting period for females (15 September- 15 October) compared with no rutting period during fall. During winter time, both sexes retain low movements, mainly caused by energy saving actions. A distinct crepuscular rhythm was exhibited during the summer and fall season, movements were more intense during dawn and dusk hours. No distinct crepuscular rhythm was noticed during winter and spring seasons. The traffic intensity at highway E6 in Southwestern Sweden increases during the morning hours and reaches its maximum during midday. Moose in southwestern Sweden crossed highway E6 more often at night time than day time. Thus highway crossings by moose occurred at times of peak moose movements, and traffic volume had lower importance.

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