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International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Communications support for the X-33 requires addressing several unique challenges to meet program and range safety requirements. As an avenue to minimize costs, the program has reduced requirements to the communications system, which lowered the cost of networking the extended range. Cost trade-offs showed that by lowering the telemetry data rate from 2 Megabits per second to 1.440 Megabits per second that significant cost avoidance could be realized. Also, by adopting standard telecommunications data rate for the uplink data stream, an efficient and integrated solution for the extended range communications could be supported. Meeting the program requirements as well as range safety requirements for this effort are critical to the success of the program. This paper describes some of the important requirements driving the design of the extended range communications support and the design of the system to meet those requirements.

The machair is a coastal grassland system found only in parts of northern and western Scotland and Ireland. Despite its limited geographic distribution, machair landscapes have high ecological, geomorphological, and cultural significance, as recognised by numerous conservation designations and legislation. In January 2005 a severe storm caused extensive damage in the Outer Hebrides, drawing attention to the sensitivity of the machair coast to erosion. The aim of this research was to investigate variations and trends in the sensitivity of three field sites within the South Uist machair to soil and coastal erosion, and to interpret measured change alongside analysis of historic climate data. Two of the sites selected, Cille Pheadair and Staoinebrig, experienced some of the most dramatic geomorphological changes associated with the 2005 storm, while the third site, Milton, appeared to be more resistant to change. A combination of fieldwork, laboratory tests, and archive work was used to obtain and analyse information about sediment budgets, shoreline indicator change, and sediment erodibility, along with contextual climatic information. A key result of this work is the provision of a detailed framework of short-medium term cyclical changes and fluctuations in the coastal change, which provides a context for interpreting and responding to longer term trends in erosion and/or accretion. Results indicated high spatial and temporal variability in the erodibility of machair soils and landforms, with no clear relationship between climatic factors and rates of erosion. Considerable short-term variations in beach volume and the position of dynamic shoreline indicators caution against the relaibility of using ‘snap-shot’ historic datasets to infer long-term rates of change. It is proposed that the machair landscape currently functions in a state of highly dynamic equilibrium, which has been maintained over the last ~130 years. While storm events such as the January 2005 storm have locally dramatic consequences, they do not appear to have disrupted the overally physical and ecological functions of the system. This contribution is particularly timely given current concerns for the future of the machair landscape under predicted sea-level and climate change scenarios, and the potential for inappropriate hard-engineering responses to the perceived risk.

Two Differential GPS (DGPS) stations were set up on Storglaciären in the upper and lower part of the ablation area to study short term variations of Storglaciären’s motion. The study period lasted from April to July 2009 and the DGPS logged data every second. Station 14, was situated over an overdeepening in the subglacial bedrock topography in the upper part of the ablation area, and was functioning the whole study period. Station 7, situated in the lower part of the ablation area, only lasted for nine days and only overlapped five days with station 14. There was a clear lag in ice motion between the two stations which indicates longitudinal coupling between the upper and the lower part of the ablation area. Station 14 pushed from up-glacier during the first acceleration event at the 24th of April and when the velocity decreased station 7 pulled from down-glacier.  The total movement of the DGPS station was 26 m during the study period. The velocity was well correlated to the external changes in temperature and precipitation. It appears to be eleven days lag in response time from April to middle of May, but after mid May the glacier responded directly to melt acts such as temperature changes and precipitation events. The delay most likely depended on the hydrological system was not entirely evolved during early spring. During the summer the system evolves which makes the glacier to respond directly to external changes. There were four major acceleration events during the study period and after the accelerations the velocity went back to the same low state as before. These cannot be interpreted as spring events as spring events should lead to an increase in the overall velocity. The temperature fluctuated during the whole study period which affects the melting rate and input and development of the hydrological system. To get a clear spring event a marked and substantial onset of melt season is needed. / Två differentiella bärvägs GPS (DGPS) stationer sattes upp på Storglaciären på den övre och lägre delen av ablations området för att studera korttidsvariationer i isflöde. Fältundersökningen pågick under april till juli 2009 och DGPS loggades varje sekund. Station 14 är placerad vid en överfördjupning i bottentopografin i den övre delen av ablationsområdet och var i gång under hela studien. Station 7 fungerade endast i nio dagar och är placerad vid den lägre delen av ablationsområdet samt överlappade under endast fem dagar med station 14. Det finns en tydlig fördröjning mellan de två stationerna i isrörelse vilket indikerar en longitudinell koppling mellan den övre och undre delen av ablationsområdet. Före den 24 april reagerade station 14 snabbare än station 7. Efter en kraftig acceleration vid station 14 den 24 april skedde det en förändring till att den nedre delen av ablationsområdet reagerade snabbare än den övre delen. Den totala förflyttningen av station 14 var 26 m under mätperioden. Hastigheten är korrelerad med externa förändringar i temperatur och nederbörd. Under april till mitten av maj var det en förändring i reaktionstid på elva dagar men den övergick under sommaren till att reagera direkt på förändringar i temperatur och nederbörd. Förskjutningen berodde troligtvis på att det hydrologiska systemet inte var tillräckligt utvecklat. Under sommaren utvecklas systemet vilket leder till att glaciären reagerar snabbare på externa förändringar. Det förekom fyra större accelerationshändelser under fältperioden. Efter de observerade accelerationerna gick hastigheten tillbaka till samma nivå. Dessa accelerationshändelser kan inte tolkas som våracceleration. En våracceleration innebär att den generella hastigheten hos glaciären ökar till en ny högre nivå. Detta kan bero på att temperaturen skiftade under hela fältperioden som styr smältning, isflöde och utveckling av det hydroligiska systemet. För att få en tydlig ”spring event” måste smältsäsongens nå en tydlig början och forstätta så kontinueligt.

Two wild blueberry fields were selected in central Nova Scotia, to characterize and quantify the spatial pattern of variability in soil properties, leaf nutrients and fruit yield, identification of yield influencing soil properties, and to develop management zones for site-specific fertilization. A combination of classical statistics, geostatistical analysis and mapping in Arc GIS 9.3 indicated substantial variation within field. The stepwise regression suggested that the soil EC, horizontal co-planar geometry (HCP), inorganic nitrogen and moisture content were major yield influencing factors. The cluster analysis of the soil variables with the fruit yield also indicated that HCP, inorganic nitrogen, EC, SOM, and ?v were closely grouped with the fruit yield at a similarity level greater than 70%. Based on the results of this study the wild blueberry fields can be divided into different management zones for variable rate fertilization to improve crop production, increase revenue, and reduce potential environmental contamination.

Detailed soil and water data are essential to ensure the optimum long-term management of fields. The objective of this study was to estimate water table depths, spatially variable and layered soil properties using electromagnetic induction methods. Soil samples were collected and analyzed within two wild blueberry, a soybean-barley and a pasture fields. Observation wells were installed. The DualEM-2 was calibrated to predict the soil properties and groundwater depths. The apparent ground conductivity (ECa) and water table depths were measured simultaneously from each well, before and after every significant rainfall for three consecutive days. Comprehensive surveys were conducted in selected fields to measure ECa with DualEM-2. Survey data were imported in C++ program to estimate layered soil properties using mathematical models. Regression models were developed to predict soil properties and groundwater depths. The predicted soil properties and groundwater table maps were generated. This information can help to develop variable rate technologies.

Autonomous Vehicles (AV) can navigate itself from point `A' to point `B' without the aid of humans. Research on autonomous vehicles were primarily focused on the localization, navigation and path planning schemes. This led to numerous methods in each of the elds of focus. This research focuses on creating a scheme for the autonomous vehicle to navigate using minimal sensors and get maximum data/infor- mation from the map. At rst a digital map contains various structures and each has an associated database. This database contains the details of the environment. At present these data are manipulated for use by humans and for this map to be used with autonomous vehicle require more sensors. This work designs maps for use with autonomous vehicle and navigates using di erential GPS (dGPS) of high accuracy for localization. Then the vehicle gets path and directions from digital map and nav- igates using multiple waypoints that are provided by the path. Finally, the scheme is tested and demonstrated through simulation and test results.

Made available in DSpace on 2014-06-11T19:22:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T19:07:52Z : No. of bitstreams: 1 dalbelo_lfa_me_prud.pdf: 1258749 bytes, checksum: 413bf515eb63448ca76790ba3eb43c75 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Atualmente é cada vez mais presente na comunidade civil a utilização do Global Positioning System (GPS). Um dos métodos de posicionamento GPS de grande destaque é o Differential GPS (DGPS). Esse método utiliza dois receptores, um como base e outro como móvel. O DGPS tem como princípio básico considerar a alta correlação dos erros provocados pela ionosfera, troposfera e órbita dos satélites. No entanto, com o afastamento entre o usuário e a estação base, a eficiência do método diminui, pois a correlação dos erros é reduzida. Mas, quando se utiliza uma rede de estações de referência, pode-se ter uma melhor modelagem dos erros na área de abrangência da rede. Surge então o conceito de DGPS em Rede (DGPSR). Alguns experimentos realizados com o DGPSR em modo pós-processados apontaram acurácia da ordem de 50 cm. Portanto, nesta pesquisa foi proposta a implementação do DGPSR em tempo real. As correções DGPSR são calculadas em tempo real por meio dos dados obtidos via Internet utilizando o protocolo Ntrip (Networked Transport of RTCM via Internet Protocol). Para isso, foram introduzidas várias alterações no software BNC, software este que foi desenvolvido pelo BKG e realiza a função do NtripClient. No que concerne às estações de referência GPS, foram utilizados dados da rede GNSS do oeste do estado de São Paulo (Rede GNSS/SP). A rede está composta, até o momento, por 10 receptores de alta tecnologia que podem ser conectados diretamente a Internet. Com relação aos resultados pode-se observar que o DGPSR utilizando 4 estações de referência apresentou melhorias de até 32% em planimetria e de 28% em altimetria, quando comparados ao DGPS utilizando somente uma estação de referência. Com relação a avaliação da latência pode-se verifica que latências de até 12 segundos parecem não causar influência nos resultados. / Nowadays, the Global Positioning System (GPS) has been very used by the civil community. One of the GPS positioning methods that have been emphasized is the Differential GPS (DGPS). In this method, two receivers are used. One of them as base and the other as rover station. The DGPS has the basic concept of considering high correlation of the errors caused by ionosphere, troposphere and satellite orbits. However, with the baseline growth the method efficiency decreases, because the errors correlation is reduced. But, using a reference station network it is possible to obtain an error modeling in the area of the network, using the network DGPS concept. Some experiments accomplished with DGPSR post processed mode presented promising results. Accuracy better than 50 cm was obtained. Therefore, in this research the goal is to implement the DGPS in real time. The corrections will be computed through data received by Internet using the Ntrip (Networked Transport of RTCM via Internet Protocol). In order to accomplish that, it was implemented several modifications in the BNC software. This software was developed by BKG and make the function of a NtripClient. It will be used a GPS network that is set up in the west of São Paulo State. This network is composed by 10 receivers of high technology that can be directly connected by Internet. Regarding the results, the DGPSR using 4 reference stations showed improvements of up to 32% in planimetry and 28% in altimetry when compared to pure DGPS. Regarding the assessment of latency it was noted that latencies of up to 12 seconds seems not to cause influence the results.

The aim of this thesis was to create an information system which consists of a mobile application, server and web application. Mobile application is designed for operating system Android and it is used for sending GPS coordinates of mobile devices to the server. These data are later processed by server and stored in database. Web application displays the current location of mobile devices in user group on a map, it also displays location history and statistics. Accuracy of the station location can be enhanced by using DGPS assuming that one of stations in a group does not change its location. The system was designed and then developed using modern web technologies and frameworks including PhoneGap, Ionic, Node.js, Express, MongoDB, Mongoose and AngularJS. Further measurements, that were performed, are supposed to present the effect of DGPS to location accuracy determination.

Scene mapping is an integral part of processing a forensic scene with scattered human remains. By utilizing the appropriate mapping technique, investigators can accurately document the location of human remains and maintain a precise geospatial record of this evidence at a scene. Global positioning system (GPS) units have been used for years to survey the spatial distribution of large-scale archaeological sites. However, differential global positioning (DGPS) unit now provide decreased positional error suitable for small-scale surveys, such as forensic scenes. Because of the lack of knowledge concerning this utility in mapping a scene, controlled research is necessary to determine the practicality of using DGPS in mapping scattered human remains in different environments. The purpose of this research is to quantify the accuracy of a DGPS unit for mapping skeletal dispersals and to determine the applicability of this utility in mapping dispersed remains. First, the accuracy of the DGPS unit was determined using known survey markers in different environments. Secondly, several simulated scenes were constructed and mapped in open, tree-covered, and structure-obstructed environments using the DGPS. Factors considered included the extent of the dispersal, data collection time, and the use of offsets. Data were differentially postprocessed and compared in a geographic information system (GIS) to evaluate the most efficient recordation methods. Results of this study show that the DGPS is a viable option for mapping human remains in open areas. Furthermore, guidelines for accurate scene mapping using a DGPS unit will be provided, along with a discussion concerning the integration of DGPS into GIS for scene analysis and presentation