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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.
201

SEA SURFACE SCATTERED GPS SIGNAL DETECTION AND APPLICATION

Yi-qiang, Zhang, Qi-shan, Zhang, Dong-kai, Yang, Bo-chuan, Zhang, Rong-lei, Hu, Zi-wei, Li 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Background and advantages of GPS based Remote Sensing are introduced, characteristics of forward scattered GPS signal such as polarization change, cross-correlation power variation, code delay due to the wave travel distance difference between direct and scattered signal, and cross-correlation power expansion due to sea surface roughness are discussed in detail. Working principle of the self-developed delay-mapping receiver is also presented. First data collection campaign is done at Inshore of BOHAI ocean with the delay-mapping receiver mounted on an airplane. Results show that the reflected signals has much variation than the direct signals, the code delay of the reflected signals varies as the receiver height and satellite elevation angle changes and expansion of the cross-correlation due to the wind driven surface was also demonstrated.
202

TIME SYNCHRONIZATION AND FREQUENCY PRECISION CONTROL AMONG MULTIPLE BASE STATIONS IN GPS

Haifang, Wang, Qishan, Zhang 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / In this paper, we develop a method for achieving high precision of time and frequency synchronization among multiple base stations in GPS system. We first describe the basic theory of timing and frequency checking, and then analyze several error sources which influence the precision of time and frequency synchronization. Furthermore, we derive explicit formula for calculating the precision of time and frequency. Tested results have indicated that our method can indeed achieve very high time and frequency precision.
203

Advances in Telemetry Capability as Demonstrated on an Affordable Precision Mortar

Don, Michael L. 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper presents three telemetry techniques demonstrated on an affordable precision mortar that allowed the guidance, navigation, and control (GNC) system to be effectively analyzed. The first is a technique for the real-time integration and extraction of GPS data into a sensor telemetry stream. The second is a method for increasing telemetry bandwidth by saving a short period of high rate data and then broadcasting it over the rest of the flight test. Lastly, I present an on-board data storage implementation using a MicroSD card.
204

GNSS Based Attitude Determination for Small Unmanned Aerial Vehicles

Pinchin, James Thomas January 2011 (has links)
This thesis is concerned with determining the orientation of small Unmanned Aerial Vehicles(UAVs). To make commercial use of these aircraft in aerial surveying markets their attitude needs to be determined accurately and precisely throughout a survey flight. Traditionally inertial sensors have been used on larger aircraft to estimate both position and orientation in combination with Global Navigation Satellite Systems (GNSS). High quality inertial sensors have many downsides when used on the small UAV. They are expensive, power hungry and often heavy. Inertial sensors are vulnerable to vibration, high acceleration, high rotation rate and jerk. All of these are present on the small UAV. This thesis identifies GNSS attitude determination as a potentially suitable alternative to inertial techniques. Carrier phase GNSS attitude determination uses three or more GNSS receivers with antennas separated by a short baseline to estimate the orientation of the UAV. This technique offers low cost, high accuracy and drift-free attitude estimates. To be successfully used it requires removal of the biases present in the received GNSS signals and estimation of the integer cycle ambiguity present in the carrier phase measurement. This thesis presents and examines the state of the art techniques for removing these biases and estimating an integer cycle ambiguity using a priori measurement of the interantenna distance. In this work a novel method is developed which uses this a priori baseline measurement to validate estimates of the carrier phase ambiguities. In order to test these methods data has been gathered using low cost, commercially available GNSS receivers and antennas. This is the first work in which modern, low cost, GNSS equipment has been tested for use in attitude determination. It is found that the state of the art carrier phase GNSS attitude determination methods can provide an accurate attitude estimate for every set of measurements from the GNSS receivers. However, a real UAV flight indicates that the low cost GNSS equipment does not track the GNSS signals throughout the flight. Signal outages, cycle slips and half cycle ambiguous carrier phase measurements occur due to rapid UAV manoeuvres. Having identified this problem this work goes on to replicate and quantify it through the use of a GNSS hardware simulator. Algorithms are then devised to increase the availability of the GNSS attitude solution throughout the tracking difficulties. Complete GNSS signal tracking failures are overcome through the innovative use of kinematic and dynamic attitude models. Both types of model give an attitude solution throughout GNSS signal tracking problems without adding significant cost or weight to the system. When tracking of the GNSS carrier phase signal is possible, novel use of the carrier phase triple difference observable allows the attitude rate to be estimated even when the carrier phase measurements are half cycle ambiguous. It is shown that integer and half integer cycle slips can be removed from the measurement through the combination of the modelling and triple difference techniques. The attitude output of both modelling and triple difference methods is used to resolve half cycle ambiguities and make full use of half cycle ambiguous data where previously it could not have been used. Success rates of up to 99.6% have been achieved for half cycle ambiguity resolution. As a result precise and accurate GNSS attitude solutions are available at nearly every epoch for which a carrier phase measurement is output by the GNSS receivers. When no measurement is available the attitude solution gracefully degrades over time. This work makes reliable, accurate, low cost attitude determination possible on mini-UAVs.
205

Temporal variation and inter-relationship of movement and resource selection of red deer (Cervus elaphus) with respect to climate: a case study

Hu, Qinglin January 2006 (has links)
Red deer (Cervus elaphus) is one of at least 31 herbivorous exotic mammals existing in New Zealand. All of these species have the potential to affect environmentral and production values. Reducing their impacts on their values, strengthening effective managements are important issues to a variety of agencies within New Zealand including the Department of Conservation (DOC), Ministry of Agriculture and Forestry (MAF), local and regional governments. This research studied animal movement pattern and habitat use of 2 GPScollared red deer in the Canterbury high country and found (1) deer movement was affected by climatic variables such as rainfall and temperature, which had positive or negative effect on it, and had seasonal variation; (2) deer had dominant landcover use categories, depending on climate, season, and individual characteristics (3) deer had different movement patterns in terms of hourly distances. The purpose of the study is to draw accurate inferences from spatially explicit data for biosecurity managers and policy-makers through: (1) using global positioning system (GPS) as a tool to elucidate the application of GPS on red deer in wildlife management; (2) Animal Movement Analysis Arc View® 3.2 Extension under Arc View® Geographic Information System (GIS); (3) Animal movement analysis which used Generalized Additive Models (GAMs) to show how the movement of red deer was affected by different periods of time, seasons months and climatic variables (for example, rainfall and temperature).
206

The development, implementation and evaluation of prescribing guidelines in general practice

Watson, Margaret C. January 1998 (has links)
No description available.
207

Make My Map in Google: Overview

Mosqueda, Martha, Hongu, Nobuko 07 1900 (has links)
4 pp. / (Make My Map in Google (Part 1: Overview, Part 2: Detailed) GPS Watches for Measuring Energy Expenditure during Physical Activity / Maps are a valuable tool among professionals including engineers, environmental specialists, and city developers. Online mapping using GPS has gained popularity in vehicles and cell phones. Recently, online mapping can be used to create your own map (Google My Map) by adding personal photos, related website links, and collaborating with others. Online mapping has now become useful and fun for all ages in a variety of settings. The fact sheets provide a basic (Part 1: Overview) and detailed (Part 2: Detailed) how-to guide to Make a Map in Google [My Maps] using a GPS receiver or GPS watch, as well as enhancing those maps into a poster. We also included interesting facts and useful tips for readers. This article can be used as a guide to encourage youth to map their favorite places, as well as share these places with other youth, friends, family, community groups and organizations.
208

Make My Map in Google: Detailed

Mosqueda, Martha, Hongu, Nobuko 07 1900 (has links)
4 pp. / "(Make My Map in Google (Part 1: Overview, Part 2: Detailed) GPS Watches for Measuring Energy Expenditure during Physical Activity" / Maps are a valuable tool among professionals including engineers, environmental specialists, and city developers. Online mapping using GPS has gained popularity in vehicles and cell phones. Recently, online mapping can be used to create your own map (Google My Map) by adding personal photos, related website links, and collaborating with others. Online mapping has now become useful and fun for all ages in a variety of settings. The fact sheets provide a basic (Part 1: Overview) and detailed (Part 2: Detailed) how-to guide to Make a Map in Google [My Maps] using a GPS receiver or GPS watch, as well as enhancing those maps into a poster. We also included interesting facts and useful tips for readers. This article can be used as a guide to encourage youth to map their favorite places, as well as share these places with other youth, friends, family, community groups and organizations.
209

Culture and mental distress : causal attributions and pathways to seeking help

Sheikh, Shaheen January 2000 (has links)
No description available.
210

The changing role of primary care with problem drinkers : an exploration of the interface between the general practitioner and the practice nurse

Deehan, Anna Marie January 1999 (has links)
No description available.

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