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Dissertations / Theses on the topic 'GPS accuracy'

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Published: 4 June 2021
Last updated: 1 February 2022

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1

Vodhanel, Michael Thomas. "Problems in GPS Accuracy." Scholarship @ Claremont, 2011. http://scholarship.claremont.edu/cgu_etd/22.

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Improving and predicting the accuracy of positioning estimates derived from the global positioning system (GPS) continues to be a problem of great interest. Dependable and accurate positioning is especially important for navigation applications such as the landing of commercial aircraft. This subject gives rise to many interesting and challenging mathematical problems. This dissertation investigates two such problems. The first problem involves the study of the relationship between positioning accuracy and satellite geometry configurations relative to a user's position. In this work, accuracy is measured by so-called dilution of precision (DOP) terms. The DOP terms arise from the linear regression model used to estimate user position from GPS observables, and are directly related to user position errors. An analysis of the statistical properties explaining the behavior of the DOP terms is presented. The most accurate satellite geometries and worst configurations are given for some cases. The second problem involves finding methods for detecting and repairing cycle-slips in range delay data between a satellite and a receiver. The distance between a satellite and a receiver can be estimated by measuring the difference in the carrier frequency phase shift experienced between the satellite and receiver oscillators. Cycle-slips are discontinuities in the integer number of complete cycles in these data, and are caused by interruptions or degradations in the signal such as low signal to noise ratio, software failures, or physical obstruction of the signals. These slips propagate to errors in user positioning. Cycle-slip detection and repair are crucial to maintaining accurate positioning. Linear regression models and sequential hypothesis testing are used to model, detect, and repair cycle-slips. The effectiveness of these methods is studied using data obtained from ground-station receivers.
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2

Grinker, Barry. "Accuracy of shipborne kinematic GPS surveying." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26341.

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3

Heselton, Robert Reid. "Elevation Effects on GPS Positional Accuracy." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36763.

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Data from a Coarse Acquisition (C/A) Global Positing System (GPS) map-grade receiver were evaluated to assess the accuracy of differentially corrected points. Many studies have focused on the accuracy of GPS units under ideal data collection conditions. Ideal conditions allow the collection of data with four satellites (3D mode), yet field data conditions are often less than ideal. Four satellites may not always be in view because of mountainous topography, heavy forest cover, or other obstructions which block satellite signals from the receiver. This study examines GPS accuracy when four satellites are not available, instead collecting data with only three satellites (2D mode).

3D GPS points compute four unknowns: x, y , z, and clock error. In comparison, 2D GPS points are less accurate as only three unknowns are calculated: x, y, and clock error. Elevation (or z) is not computed for 2D points, causing increased error in the horizontal (x, y) measurement. The effect of elevation was evaluated on 234 2D GPS data points. These points were collected and corrected at elevation intervals of true elevation, +-25 meters, +- 50 meters, and +-75 meters. These 2D points were then compared to surveyed points to measure the effect vertical error has on horizontal accuracy. In general, the more error in the vertical estimate during correction, the greater the horizontal error.


Master of Science
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4

Eriksson, Love, and Thomas Pettersson. "Improving GPS Position Accuracy Using Particle Filtering." Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200539.

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5

Kalyanaraman, Sai K. "High Accuracy GPS Phase Tracking Under Signal Distortion." Ohio University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1251221460.

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6

Trehn, Erik. "GPS Precise Point PositioningAn Investigation in Reachable Accuracy." Thesis, KTH, Geodesi och satellitpositionering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199865.

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Accurate positioning is very important in many various applications. Today one of the mostused methods for this is DGPS, i.e. relative positioning. DGPS can be extended to aWADGPS (Wide Area DGPS) which consists of a network of reference stations which covera whole region, country or continent. This implies that you are dependent on other factors outof control of the user, and that a connection to the reference stations is needed.Precise point positioning, PPP, is an absolute positioning method where no reference stationsare involved. Ordinary single point positioning is based on broadcast ephemeris, and theaccuracy is on the 15m level. Per definition PPP is based on precise ephemeris, with muchhigher accuracy in the orbital parameters and in the satellite clock information. The resultshould therefore be more accurate. Precise ephemeris are available in different levels ofaccuracies (final, rapid and ultra-rapid) and can be downloaded from the internet for free.Precise clock files are not available as ultra-rapid and therefore it is not possible to getaccurate PPP-solutions in real-time.In Sweden there are several networks for relative positioning, e.g. through SWEPOS orEPOS. This might not be the case in other areas. As accurate PPP-solutions are not availablein real-time, PPP could be used to establish a reference station for DGPS/RTK for real-timemeasurements in those areasThe objective of this research is to evaluate precise point positioning regarding accuracy.Observation files from both IGS and SWEPOS-stations have been used in order to find out ifyou can expect the same accuracy wherever you are on earth. A couple of points have alsobeen measured only for this investigation in order to find out if the result will be the sameunder ordinary conditions. Coordinates of each point are determined with different duration ofobservation times and different level of accuracy of the ephemeris (final, rapid and ultrarapid).Bernese 5.0 and Auto-Gipsy have been used to compute the PPP-solutions and thenthe result is compared with the true position. The self-measured points are also determinedwith a WADGPS (Omnistar) in order to easily be able to compare PPP with a traditionalmethod.As expected the result becomes better for longer observation times and with higher accuracyof the ephemeris. The difference in accuracy between using rapid and final ephemeris is sosmall that it can be neglected in most applications. In almost all cases the accuracy is betterthan 10cm after only one hour of observations with rapid ephemeris. The investigation doesnot indicate significantly differences in accuracy depending on latitude and differencesbetween the self-measured points and IGS- and SWEPOS-stations can also be neglected.Using rapid or final ephemeris, the PPP-derived coordinates are much more accurate than theones obtained with Omnistar.
Noggrann positionsbestämning med hjälp av GPS har flera olika tillämpningar. En utav depopuläraste metoderna idag är DGPS, dvs. relativ positionering. WADGPS (Wide AreaDGPS) är ett nätverk av referensstationer som täcker ett större område så som ett land eller enkontinent. Detta innebär att en användare är beroende av faktorer som ligger utanför hanskontroll och av att det finns en kommunikationslänk till referensstationerna.Precise point positioning, PPP, är en absolut positioneringsmetod där inga referensstationerdeltar i beräkningarna. Vanlig enkelpunktsbestämning bygger på de bandata som kommermed satellitmeddelandet och noggrannheten ligger i allmänhet omkring 15m. PPP baseras perdefinition på precis efemerider med mycket bättre noggrannhet i bandata och satelliternasklockinformation. Resultatet bör därför bli avsevärt mycket bättre. Precisa efemerider finns iolika noggrannhetsnivåer (final, rapid och ultra-rapid) och kan laddas ner gratis från internet.Precis information om satelliternas klockor kommer inte med ultra-rapid efemerider varför detinte går att få noggranna lösningar med PPP i realtid.I Sverige finns väl utvecklade nät för relativpositionering, tex. SWEPOS eller EPOS. Så ärkanske inte fallet i andra delar av världen. Med PPP skulle man kunna etablera egnareferenspunkter och på så sätt kunna mäta i realtid med DGPS.Målet med detta examensarbete är att undersöka vilken noggrannhet som kan uppnås medPPP. Observationsfiler från både SWEPOS- och IGS-stationer har använts för att se om mankan förvänta sig samma resultat oberoende av var på jorden man befinner sig. Även någrapunkter har mätts enbart för denna undersökning för att se om resultatet blir detsamma undervanliga förhållanden. Koordinaterna för varje punkt har beräknats med olika observationstideroch olika typer av efemerider (final, rapid och ultra-rapid). Bernese 5.0 och Auto-Gipsy haranvänts för att beräkna PPP-koordinaterna, som sedan har jämförts med de sanna värdena.Egna mätta punkter har även bestämts med WADGPS (Omnistar) för att enkelt kunna jämföraPPP med en traditionell metod.Som väntat blev resultatet bättre för längre observationstider och för noggrannare efemerider.Skillnaderna i noggrannhet mellan final och rapid efemerider är så liten att den kan bortsesifrån i de flesta fall. Bortsett från något undantag är noggrannheten bättre än 10cm efter baraen timmes mätning med rapid efemerider. Undersökningen visar inte någon signifikantskillnad i noggrannhet beroende på latitud, och skillnaden mellan de egna mätta punkternaoch IGS- och SWEPOS-stationer kan också försummas. Koordinater beräknade med PPP,beräknade med rapid och final efemerider är mycket mer noggranna än de som beräknats medOmnistar.
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7

Wallerström, Mattias, and Fredrik Johnsson. "En nätverks-RTK-jämförelse mellan GPS och GPS/GLONASS." Thesis, University of Gävle, Department of Technology and Built Environment, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-130.

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Från den 1 april 2006 har SWEPOS kompletterat den befintliga nätverks-RTK-tjänsten, som dittills levererat RTK-data för GPS, med ett alternativ där RTK-data för GPS/GLONASS levereras. En del användare har rapporterat att de upplever att GPS/GLONASS inte tillför något och även att det ibland kan ta längre tid att få fixlösning. Andra användare hävdar att de nu kan använda nätverks-RTK på platser där de tidigare inte kunde mäta och är mycket positiva till GPS/GLONASS.

Syftet med detta examensarbete var att undersöka hur tillgängligheten för satellitmätning, positionsnoggrannheten och initialiseringstiden påverkades i öppna respektive störda miljöer med GPS/GLONASS jämfört med enbart GPS vid användandet av nätverks-RTK-tjänsten. Undersökningen har utförts med tre olika fabrikat av GNSS-mottagare (Leica, Topcon och Trimble), vilket även medger att en jämförelse mellan dessa till viss utsträckning kan göras.

I studien gjordes totalt 1 440 mätningar på sex punkter med kända positioner och med olika grad av sikthinder. Fixlösning uppnåddes inte inom 180 sekunder för 206 (77 för GPS/GLONASS och 129 för GPS) av de 1 440 mätningarna.

De extra GLONASS-satelliterna tillför en klar fördel när det gäller möjligheten att mäta i störda miljöer. När det gäller initialiseringstid så är dessa kortare för GPS/GLONASS. GLONASS-satelliterna ger ingen förbättring av positionsnoggrannheten. Det är till och med så att GPS får något bättre kvalitetstal i både plan och höjd i denna studie (1-3 mm bättre). För de olika fabrikaten kan det konstateras att precision och noggrannhet är likvärdiga i både plan och höjd för alla tre märken.


On the 1st of April 2006, SWEPOS complemented the existing network RTK service with corrections for the Russian satellite system GLONASS. The service had so far only provided corrections for GPS. Some users have claimed that GPS/GLONASS do not contribute at all and also that the time for initialization sometimes can be longer. However, other users insist on that they now can use network RTK in areas that earlier were impossible and they are very favourable of GPS/GLONASS.

The purposes of this diploma work were to study and examine measurements using GPS and GPS/GLONASS in areas with different degrees of visual obstacles. Corrections were provided by SWEPOS Network RTK service and availability of satellites, accuracy of position and time for initialization were evaluated. The study has been conducted with three different brands of GNSS receivers (Leica, Topcon and Trimble), which also to some extent makes a comparison between the three brands possible.

A total number of 1 440 field measurements were made on six well-known points with different degrees of visual obstacles. A fixed solution was not accomplished within 180 seconds for 206 (77 for GPS/GLONASS and 129 for GPS) of the 1 440 measurements.

The additional GLONASS satellites provide an apparent advantage regarding the possibility to measure in disturbed environments. The time for initialization is shorter for GPS/GLONASS. The GLONASS satellites do not give any improvement in accuracy of position. On the contrary, GPS receives slightly better accuracy numbers in quality for both horizontal and vertical readings (1-3 mm better). Regarding the different brands, it was found that the precision and accuracy were similar in both plane and height for all three brands.

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8

Glushik, John J. (John Joseph). "Data analysis and accuracy performance of multisite differential GPS." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12113.

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9

Forrest, Timothy Lee. "Logistic regression models for predicting trip reporting accuracy in GPS-enhanced household travel surveys." Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/4667.

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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.
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10

De, Lorenzo David S. "Navigation accuracy and interference rejection for GPS adaptive antenna arrays /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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11

Abdel-Monem, Tarek M. "INFRARED THERMOGRAPHY AND HIGH ACCURACY GPS FOR AUTOMATED ASPHALT CRACK DETECTION." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3264.

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Roads are major public assets. The USA spends billions of dollars each year on road construction and maintenance. To keep these roads in a healthy condition and for better planning and allocation of maintenance budgets, knowledge of distressed locations is needed. Roads develop cracks when they are subjected to stresses that exceed their designed criteria or their materials properties. Early detection and repair of cracks has proven to be the most cost-effective strategy in limiting the damage to roads and reducing expenditures. Various methodologies of crack detection were developed and significant techniques were made in the last few years. One of the most important recent technologies is the infrared thermography, which allows the use of infrared waves for crack detection. Another important technology is the global navigation satellite system (GNSS) which currently includes the GPS and GLONASS constellations. With the help of these systems, accurate location coordinates (longitude, latitude and altitude) up to a few centimeters were located. The objective of this research is to test the combined use of GNSS and infrared thermography in an automated system for the detection of asphalt cracks and their locations. To achieve this goal, two tests have been conducted. The first one, regarding the location tagging, was done using two pairs of GPS receivers which can detect signals from both GPS and GLONASS navigation systems in single and dual frequencies (L1 and L2). Different modes have been set to the receiver and comparison graphs were developed to compare accuracies against modes. The second test involves an infrared camera mounted on a car and moving in speeds approaching highway speed limit. The images obtained from the camera were processed using cracks detection software to analyze cracks properties (length, width, density and severity). It was found that the images that were taken by a moving infrared camera were recognized by crack detection software for moving speeds up to 50 mph. At speeds higher than 50 mph, images were blurred. As for location test, The GLONASS combined by GPS receivers got slightly better results than GPS only in both dual and single frequencies. The GLONASS satellites are not always available in view and when they are there, the number of satellites that can be detected by receiver range from one to three satellites at the most and for only a short period of time. It is recommended that future research be conducted to investigate the effect of using different camera lenses on the clarity of the images obtained as well as the effect of raising the camera level above the pavement surface in such a way that the whole lane width (12 ft.) would be covered in one image. Also the total reliance on GPS only receivers in determining cracks location has proven to be enough for this application.
M.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering
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12

Morán, Guillermo Martinez. "Results for Precise GPS Trajectography Computation without Base Station." International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596434.

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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV
The use of differential GPS post-procesing for precise trajectography computation has been widely used since early 90s. Up to recent dates, installation of a GPS receiver in a well known position (base station) has been mandatory. Operating range from this base station varies from 50 km up to 100 km, depending on the accuracy required, which impose single or dual frequency GPS technique. Nowadays, the huge amount of GPS base stations continuous logging data worldwide have allowed to improve the error models a lot. Using these precise models, it is possible to achieve centimeter accuracy in GPS trajectography by using only one GPS receiver without range to a base station restrictions. This technique is called Precise Point Positioning (PPP). The performance results for PPP obtained after a real 10 flights campaign will be presented.
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Frentzel, Jonathan Michael. "Relative Accuracy and Precision of Differentially Corrected GPS on a Moving Vehicle." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34800.

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Differential corrections provide a method to improve the real-time accuracy and precision of GPS, but there are several sources of differential corrections and each have an associated accuracy and precision. In dynamic applications, the speed and heading of the rover may also have an effect on the accuracy and precision reported by the GPS receiver. These factors may have more of an effect on one differential correction method than another. An experiment was designed to test the differential correction methods under dynamic conditions. No corrections, OmniStar HP corrections, and RT2 corrections from a local base station were tested at several speeds and headings. The experiment was designed to determine what relationship, if any, exists between these factors and positional accuracy and precision of the differential correction sources. The results of the experiment will help designers choose the most effective solution for their positioning needs. The experiment showed that local RT2 corrections offered the most precision under dynamic conditions. The precision of OmniStar HP was close to that of RT2 corrections. The system with no corrections was the least precise of the three tested. The speed and direction of the vehicle were not observed to have a significant affect on the precision of the systems tested. The type of differential corrections used was not seen to have any influence on relative accuracy. The speed and direction of the vehicle did have an influence on the relative accuracy of the systems.
Master of Science
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Khalil, Louay. "LoRa-positioning in Malmö compared with GPS: possibilities, power consumption & accuracy." Thesis, Malmö universitet, Fakulteten för teknik och samhälle (TS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20479.

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Internet of Things, blir allt större för varje dag och talas om överallt där teknik är närvarande.Större företag implementerar idéer och lösningar som är bundna till IoT, ochmindre företag följer trenden med att följa tekniska lösningar med låg strömförbrukningoch långsiktig täckning av signal. LoRaWAN möjliggör just det och utvecklas mycketsnabbt för bättre användning och bättre lösningar. Numera utvecklar och forskar företagenmycket i lösningar för smarta spårningsobjekt och i detta dokument byggs en prototypför att spåra stulna cyklar där positionsspårning experimenteras med. GPS-spårning jämförsmed LoRaWAN-spårning efter att en prototyp har byggts och utformats för att spåraen stulen cykel med båda lösningarna. Syftet med denna avhandling är att visa hur ensådan prototyp kan byggas och vad resultaten är mellan GPS-spårningen och LoRaWANspårningen.Detta koncept ger en förståelse av hur långt utvecklingen av LoRaWAN-näthar nått i en stad som Malmö i Sverige. Ena fallscenariot visar resultat av prototypensenergiförbrukning utan att cykeln stulits. Ett andra scenario visar när cykeln är stulen ochpresenterar skillnaderna i strömförbrukningen och lokaliseringens noggrannhet. I scenario1 GPS-positionering varar i 12 dagar medan LoRaWAN-positionering varar 14 dagar. Iscenario 2 är resultaten 9 dagar mot 14 dagar för GPS gentemot LoRaWAN.
Internet of Things is becoming bigger for each day and is talked about everywhere technologyis present. Major companies are implementing ideas and solutions bound to theIoT and smaller companies are following the trend in pursuing technological solutions withlow power consumption and long range coverage of signal. LoRaWAN enables just thatand is getting developed very fast for better usage and better solutions. Nowadays, companiesdevelop and research a lot in solutions for smart tracking objects and in this papera prototype to track stolen bicycles is built where tracking is experimented with. GPStrackingis compared to LoRaWAN-tracking after a prototype is been built and designedto track a stolen bicycle with both solutions. The aim for this thesis is to show how suchprototype can be built and what the results are between GPS-tracking and LoRaWANtracking.This concept gives an understanding of how far the development of LoRaWANnetworks has reached in a city like Malmö in Sweden. One case scenario shows results ofthe prototype used in reality without having the bicycle stolen. A second scenario showswhen the bicycle is stolen and presents the differences in the results of power consumptionand accuracy of localization. In case scenario 1 GPS-positioning lasts for 12 days whileLoRaWAN-positioning lasts 14 days. In case scenario 2 the results are 9 days against 14days.
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Menzori, Mauro. "Classificação da exatidão de coordenadas obtidas com a fase da portadora L1 do GPS." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18143/tde-06032006-121142/.

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A fixação das duplas diferenças de ambigüidades no processamento dos dados da fase da portadora do Sistema de Posicionamento Global (GPS), é um dos pontos cruciais no posicionamento relativo estático. Esta fixação também é utilizada como um indicador de qualidade e fornece maior segurança quanto ao resultado do posicionamento. No entanto, ela é uma informação puramente estatística baseada na precisão da medida e dissociada da exatidão das coordenadas geradas na solução. A informação sobre a exatidão das coordenadas de pontos medidos através de um vetor simples, é sempre inacessível, independente de a solução ser fixa ou “float”. Além disso, existe um risco maior em assumir um resultado de solução “float”, mesmo que ele tenha uma boa, porém, desconhecida exatidão. Por estes motivos a solução “float” não é aceita por muitos contratantes de serviços GPS, feitos com a fase da portadora, que exigem uma nova coleta de dados, com o conseqüente dispêndio de tempo e dinheiro. Essa tese foi desenvolvida no sentido de encontrar um procedimento que melhore esta situação. Para tanto, se investigou o comportamento da exatidão em medidas obtidas com a fase da portadora L1 do GPS, monitorando os fatores variáveis presentes neste tipo de medição, o que tornou possível a classificação da exatidão de resultados. Inicialmente, a partir de um conjunto de dados GPS, coletados ao longo dos anos de 2003, 2004 e 2005 em duas bases de monitoramento contínuo da USP, se fez uma análise sistemática do comportamento das variáveis contidas nos dados. A seguir se estruturou um banco de dados, que foi usado como referência na indução de uma árvore de decisão adotada como paradigma. Por último, a partir desta árvore se pôde inferir a exatidão de soluções de posicionamento obtidas com o uso da portadora L1. A validação do procedimento foi feita através da classificação da exatidão de resultados de várias linhas base, coletadas em diferentes condições e locais do estado de São Paulo e do Brasil
The most crucial step on the relative static positioning, when using the Global Positioning System (GPS) carrier phase data, is the fixing ambiguities integer values. The integer ambiguity solution is also used as a quality indicator, ensuring quality to the positioning results. In despite of its capability, the ambiguity fix solution is purely statistical information, based on the precision of measurements and completely apart from the coordinate's solution accuracy. In a single baseline processing, the positioning coordinates accuracy is always inaccessible, no matter if the final solution is float or fixed. In fact, there is some inner risk when using the float solution, although they have a good, nevertheless, unknown accuracy. Probably that is why several GPS job contractors reject the float solutions and require a new data observation, with the consequent time and money loss. This research was developed to improve that situation, investigation the inner accuracy in several GPS L1 carrier phase measurements. Checking the variable factors existing on this kind of measurement it was possible to classify the results accuracy behavior. The investigation was developed in tree steps: started with the systematic analysis of a group of L1 observation data, collected during the years: 2003, 2004 and 2005, followed by the construction of a structured data bank which generated a decision tree, performing the paradigm used to classify the accuracy of any measurement made with GPS L1 carrier phase; and ended with the research validation, through the accuracy classification that was made on several baselines, collected on different conditions and places around the state of São Paulo and Brazil
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16

Combs, Russell G. "Positional accuracy in a natural resource database : comparison of a single-photo resection versus affine registration /." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01102009-063416/.

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17

Silveira, Augusto Cesar da 1973. "Avaliação de desempenho de aparelhos receptores GPS." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257171.

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Orientador: Nelson Luis Cappelli
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
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Resumo: Este trabalho teve como principais objetivos: avaliar, comparar e analisar os diferentes aparelhos de GPS, levando-se em conta as diversas categorias, seus desempenhos com respeito a seus índices de acurácia e precisão, podendo assim, analisar os custos dos aparelhos em função dos índices de desempenho nos diversos modos de operação. Levando-se em conta que o sistema de posicionamento global por satélites (GPS) tem se tornado padrão no segmento da agricultura, baseou-se na significativa diferença de custo, acurácia e precisão entre os receptores GPS das categorias de navegação e de mapeamento e a imediatamente superior. A motivação deste trabalho deu-se, com a possibilidade de aumento do número de usuários no segmento agrícola, por meio da redução do custo dos sistemas de posicionamento e na necessidade de se conhecer a real acurácia e precisão dos receptores GPS em diversos modos de operação
Abstract: This work had as main objectives: evaluate, compare and analyze the different GPS devices, taking into account the several categories, their performance related to their accuracy and precision indicators, and in this way it may analyze the costs of devices in function of the performance indicators in the several ways of operation. Taking into account that the system of global position by satellites (GPS) has become a standard in the agriculture segment, it has been based in the significance cost, accuracy and precision differences among the GPS receptors of the navigation and the mapping categories and their immediate superior ones. The motivation of this work has been provided with the possibility of an increase of number of users in the agriculture segment through the reduction of costs of the mapping systems and the need to know the real accuracy and precision of the GPS receptors in the several ways of operation
Mestrado
Maquinas Agricolas
Mestre em Engenharia Agrícola
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18

Yi, Yudan. "On improving the accuracy and reliability of GPS/INS-based direct sensor georeferencing." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1186671990.

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19

Bilich, Andria L. "Improving the precision and accuracy of geodetic GPS: Applications to multipath and seismology." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3239388.

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20

Li, Zheng, and Zheng Li. "Improving Estimation Accuracy of GPS-Based Arterial Travel Time Using K-Nearest Neighbors Algorithm." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/625901.

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Link travel time plays a significant role in traffic planning, traffic management and Advanced Traveler Information Systems (ATIS). A public probe vehicle dataset is a probe vehicle dataset that is collected from public people or public transport. The appearance of public probe vehicle datasets can support travel time collection at a large temporal and spatial scale but at a relatively low cost. Traditionally, link travel time is the aggregation of travel time by different movements. A recent study proved that link travel time of different movements is significantly different from their aggregation. However, there is still not a complete framework for estimating movement-based link travel time. In addition, probe vehicle datasets usually have a low penetration rate but no previous study has solved this problem. To solve the problems above, this study proposed a detailed framework to estimate movement-based link travel time using a high sampling rate public probe vehicle dataset. Our study proposed a k-Nearest Neighbors (k-NN) regression method to increase travel time samples using incomplete trajectory. An incomplete trajectory was compared with historical complete trajectories and the link travel time of the incomplete trajectory was represented by its similar complete trajectories. The result of our study showed that the method can significantly increase link travel time samples but there are still limitations. In addition, our study investigated the performance of k-NN regression under different parameters and input data. The sensitivity analysis of k-NN algorithm showed that the algorithm performed differently under different parameters and input data. Our study suggests optimal parameters should be selected using a historical dataset before real-world application.
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21

Konecký, Jakub. "Měření vzdáleností a plochy pomocí GPS." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217982.

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The aim of my dissertation work was to create an application for pocket PC with operating system Windows Mobile and touch screen, an application that would enable to position the current location of the pocket PC based on the GPS data, on distance measurement between two and more points of which the location is obtained from GPS, and on measurement of territory surface defined by certain number of points obtained from the GPS. The application also enables to display the characteristics of the received GPS signal, information about the number of visible satellites and also information about maximum deviation from positioning. In order to increase the accuracy of the positioning, an averaging function has been implemented. As additional function, a possibility of route location has been created. It measures the passed distance and records some other route characteristics. The application has been successfully tested on pocket PC E-ten M600+ and GPS receiver Navilock but it has been designed with general-purpose and should be compatible with all devices working with operating system Windows Mobile and touch screen. The text section of my dissertation work describes the positioning principle on the basis of satellites with known position, deals with the accuracy of these systems and describes few possibilities how to increase their accuracy. It also discusses the NMEA 0183 Protocol that is used by the majority of GPS modules for communication. The text section also describes several mathematic and cartographic calculations needed for realization of the application. In the end of the text section there is a detailed description of the created application.
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Miles, Luke G. "Global Digital Elevation Model Accuracy Assessment in the Himalaya, Nepal." TopSCHOLAR®, 2013. http://digitalcommons.wku.edu/theses/1313.

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Digital Elevation Models (DEMs) are digital representations of surface topography or terrain. Collection of DEM data can be done directly through surveying and taking ground control point (GCP) data in the field or indirectly with remote sensing using a variety of techniques. The accuracies of DEM data can be problematic, especially in rugged terrain or when differing data acquisition techniques are combined. For the present study, ground data were taken in various protected areas in the mountainous regions of Nepal. Elevation, slope, and aspect were measured at nearly 2000 locations. These ground data were imported into a Geographic Information System (GIS) and compared to DEMs created by NASA researchers using two data sources: the Shuttle Radar Topography Mission (STRM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Slope and aspect were generated within a GIS and compared to the GCP ground reference data to evaluate the accuracy of the satellitederived DEMs, and to determine the utility of elevation and derived slope and aspect for research such as vegetation analysis and erosion management. The SRTM and ASTER DEMs each have benefits and drawbacks for various uses in environmental research, but generally the SRTM system was superior. Future research should focus on refining these methods to increase error discrimination.
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Xu, Chunchun. "High Accuracy Real-time GPS Synchronized Frequency Measurement Device for Wide-area Power Grid Monitoring." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27007.

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Frequency dynamics is one of the most important signals of a power system, and it is an indicator of imbalance between generation and load in the system. The Internet-based real-time GPS-synchronized wide-area Frequency Monitoring Network (FNET) was proposed to provide imperative frequency dynamics information for a variety of system-wide monitoring, analysis and control applications. The implementation of FNET has for the first time made the synchronized observation of the entire U.S. power network possible with very little cost. The FNET is comprised of many Frequency Disturbance Recorders (FDR) geographically dispersed throughout the U.S. and an Information Management System (IMS), currently located at Virginia Tech. The FDR works as a sensor, which performs local measurements and transmits calculations of frequency, voltage magnitude and voltage angle to the remote servers via the Internet. Compared with its commercial counterpart Phasor Measurement Unit (PMU), FDR provides less expensive version for networked high-resolution real-time synchronized. The improved single phase algorithm in the FDRs made it possible to measure at 110V level which is much more challenging than PMUs due to the noise involved at this level. This research work presents the challenges and issues of both software and hardware design for the novel measurement device FDR, which is one of the devices with the highest dynamic precision for power system frequency measurement. The DFT-based Phasor Angle Analysis algorithm has been improved to make sure the high-resolution measuring FDRs are installed at residential voltage outlets, instead of substation high-voltage inputs. An embedded 12-channel timing GPS receiver has been integrated to provide an accurate timing synchronization signal, UTC time stamp, and unit location. This research work also addresses the harmonics, voltage swing and other noise components' impacts on the measurement results, and the optimized design of filters and a coherent sampling scheme to reduce or eliminate those impacts. The verification test results show that the frequency measurement accuracy of the FDR is within +/-0.0005Hz, and the time synchronization error is within +/-500ns with suitable GPS antenna installation. The preliminary research results show the measurement accuracy and real-time performance of the FDR are satisfactory for a variety of FNET applications, such as disturbance identification and event location triangulation.
Ph. D.
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Singh, Mahendra, Stuart McNamee, Rick Navarro, Amy Fleishans, Louie Garcia, and Allen Khosrowabadi. "IMPROVING PERFORMANCE OF SINGLE OBJECT TRACKING RADAR WITH INTEGRATED GPS/INS." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/608266.

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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California
A novel approach combines GPS receiver technology with micro-electromechanical inertial sensors to improve performance of single object tracking radar. The approach enhances range safety by integrating an airborne Global Positioning System/Inertial Movement Unit (GPS/IMU) with a C-band transponder to downlink time-space-position information (TSPI) via FPS-16 instrumentation radar. This improves current telemetry links and the Range Application Joint Program Office (RAJPO) data link for downlinking TSPI because of the inherent long-range advantage of the radar. The goal of the project is to provide distance independent accuracy, and to demonstrate continuous 15-meter or better position accuracy over the entire flight envelope out to slant ranges up to 1,000 Km with at least 50 updates per second. This improves safety coverage for the wide area flight testing. It provides risk reduction for the Air Force Flight Test Center (AFFTC), Edwards Air Force Base, California and other ranges planning TSPI system upgrades.
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Žvironas, Andrius. "GPS Trimble R8 GNSS prietaiso tikslumo įvertinimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20090114_155221-31440.

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Nagrinėjama GPS prietaiso Trimble R8 GNSS tikslumas. Tirta sudaryto geodezinio pagrindo tikslumo charakteristikos, remiantis atliktais GPS (globalinės padėties taškų nustatymo sistema) matavimais ir išskaičiuotomis geodezinio pagrindo punktų koordinatėmis. Atlikta analizė rodo, kad anksčiau sudarytas trianguliacijos tinklas yra aukšto tikslumo ir pilnai tenkina bei ateityje tenkins Kauno miesto geodezinio pagrindo reikalavimus, todėl punktų koordinates keisti būtų netikslinga. Apskaičiuotąsias GPS matavimais punktų koordinates vietinėje sistemoje tikslinga būtų taikyti, vykdant tik aukšto tikslumo geodezinius darbus.
The analysis GPS instrument Trimble R8 GNSS accuracy. Precision characteristics of performed geodesic basis were examined according to GPS (global location point determination) measurement and calculated coordinates of points of geodesic basis. The analysis showed, that triangulation net that was made earlier is of high precision and meets completely and will meet in the future the needs of city geodesic basis, therefore it is not expedient to change the coordinates of the points. The application of point coordinates calculated according to GPS (global location point determination) measurement in local system would be expedient when prosecuting geodesic works of high precision only in the city and coordinates of old planimetric net should be used for performance of gross scale topographical photos, for land cadastral works and other works of applied geodesy.
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Jokešová, Markéta. "Možnosti využití GPS při analýze silničních nehod." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-232609.

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Diploma thesis deals with the possibilities of using GPS when analysing road accidents. The history and structure of U.S. global positioning system, Russian GLONASS system and European Galileo system are described. GPS receivers are sorted out by the possibility of use. The thesis deals with the methods of refinement GPS and how the vehicles can be monitored using GPS. In the practical part of this diploma thesis measurements with several types of navigations were made. And a comparison of accuracy of measured data with the real situation where the car was found at the moment of measuring followed and how fast was gone.
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Dongkai, Yang, Kou Yanhong, Chen Zhi, Zhang Qishan, and Xu Aigong. "TEST AND EVALUATION OF GPS/DR APPLICATION FOR CAR NAVIGATION SYSTEM." International Foundation for Telemetering, 2003. http://hdl.handle.net/10150/605598.

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International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Global Positioning System (GPS) was analyzed in terms of its repeatable accuracy, UTM projection for 2D plane coordinate system, satellite visibility performance and the horizontal dilution of positioning (HDOP). The principle of Dead Reckoning together with body coordinate system transformation was introduced. The complementary performance of GPS and DR, and GPS/DR integration using gyroscope and accelerometer were given. Test results were demonstrated that the repeatable accuracy of GPS alone is about 10 meters in open air, and DR can provide continuous positioning output within sufficient accuracy when GPS signal is outage.
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28

El, Hajj Mireille. "The impact of the new GPS signals on positioning accuracy for urban bus location based services." Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/56401.

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Increased bus patronage has the potential to facilitate the achievement of transport sustainability in cities in the developed and developing countries by alleviating congestion and its consequences including delays and pollution. However, this requires bus-friendly policies and a significant improvement in the efficiency of urban bus operations. Such operations consist of a large number of location based services such ‘countdown’ which requires the computation of bus arrival times at bus stops. However, to date there is a lack of agreement globally on the location based services and their key performance indicators expressed in the form of the required navigation performance parameters of accuracy, integrity (quality of or confidence in the position accuracy), continuity of service, and service availability. As a result of this, there is currently no optimal positioning system specification for bus operations. This thesis addresses these two issues and contributes to the field by firstly creating a comprehensive list of location-based services together with the required navigation performance for some of the applications. This is through a comprehensive literature review, consultation with a subject matter expert, and augmentation with, for the first time, a global survey of the major bus operators. Secondly, by demonstrating that a significant improvement in positioning accuracy is achievable with multi-constellation differential positioning. This is achieved through a comparative analysis of GPS only and augmentation with GLONASS and local differential positioning. Thirdly, the benefits of the new signals are demonstrated in the measurement and position domains, using established and novel mathematical models. The thesis analyses in detail the measurement qualities of the legacy and new signals in the measurement and position domains. The results of the former demonstrate the superiority of the L5 signal both in terms of signal strength and measurement precision, over the legacy L1 coarse acquisition (C/A) code measurements, with the new L2C as the weakest. The results of the position domain analysis show a significant improvement in positioning accuracy over the use L1 C/A code measurements alone, as a result of the mitigation of the ionospheric error through the combined use of the L1 C/A and L2C code measurements. The improvements in 3D positioning accuracy at the 95th percentile range from 22% (6m) in the clean (unobstructed environment) to 48% (13.66m) in the urban environment. The corresponding 2D horizontal positioning accuracy at the 95th percentile are 3.33m and 9.03m respectively. These improvements would not only enable more of the location based services to be supported but also facilitate the achievement of higher accuracy performance when using carrier phase measurements through enhanced ambiguity resolution.
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Ramudzuli, Zwivhuya Romeo. "Investigation into a GPS time pulse radiator for testing time-stamp accuracy of a radio telescope." Master's thesis, Faculty of Engineering and the Built Environment, 2018. http://hdl.handle.net/11427/29995.

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The MeerKAT radio telescope in South Africa is required to tag the arrival time of a signal to within 10 ns of Coordinated Universal Time (UTC). The telescope has a local atomic clock ensemble and uses satellite based remote clock comparison techniques to compare the telescope time to UTC. The master clock timing edge is distributed to each telescope antenna via an optical fibre precise time transfer. Although the timing accuracy of the telescope time was measured internally by the telescope, there is a need for an independent method to verify how well each antenna and its associated processing stages are aligned to UTC. A portable GNSS time-pulse radiator (GTR) device for testing the time-stamp accuracy was developed. The GTR was calibrated at the National Metrology Institute of South Africa and laboratory characterisation tests measured its RF timing pulse to be 1.32 ± 0.100 µs ahead of the UTC second. The telescope’s time and frequency reference clock ensemble consists of two hydrogen masers, an ultrastable crystal and GPS disciplined Rubidium clocks. During operation, the GTR radiates a broadband GPS time synchronised RF timing signal at a known distance from the telescope antennas and the corresponding timestamps were compared to the expected value. Recent GTR timing tests performed on one of the MeerKAT antennas showed that the telescope’s generated timestamps associated with the GTR’s RF timing signal coincided with the expected delay of approximately 16 ± 0.1 µs measured from an antenna 4.8 km away from the telescope’s master clock transmitter. Ultimately we used the GTR to verify that the telescope time and UTC were aligned to within 100 ns. Future work is planned to improve the profile of the transmitted signal and timing critical hardware in order to reduce the GTR’s error budget.
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30

Mathur, Navin G. "Feasibility of using a low-cost inertial measurement unit with centimeter accuracy differential global positioning system." Ohio University / OhioLINK, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1181173720.

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31

Switzer, Earl R., John Wrin, and James Huynh. "COMBINING TECHNOLOGIES TO FOSTER IMPROVED TSPI ACCURACY AND INCREASE SHARING OF THE FREQUENCY SPECTRUM." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608757.

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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada
The loss of radio frequency (RF) spectrum for use in testing has steadily increased the likelihood that users of the few remaining frequencies available to test ranges will experience scheduling conflicts and interference with nontest users. A gradual increase in the base of test customers engaged in scientific, military, and commercial R&D, point toward a near term situation in which more test customers will be competing for fewer frequencies. The test ranges, often operating in close geographical proximity with other communications-intensive functions as well as with each other, will also encounter increasing out-of-band and adjacent-channel interference. This projected growth of R&Drelated testing constrained to operate in a diminished RF spectrum (and a more confined test space), will undoubtedly stimulate the development of new products that make more efficient use of the RF spectrum. This paper describes one such innovative approach to spectrum sharing. The authors assess the operational need for an affordable miniaturized avionics instrument package based on a C-band radar transponder integrated with a Global Positioning System/Inertial Measurement Unit (GPS/IMU). The proposed approach would make use of frequencies already allocated for use by existing C-band aeronautical transponders. It would augment the format of the transponder output data to include the vehicle position obtained from an onboard GPS/IMU. Existing range instrumentation radars, such as the venerable AN/FPS-16, could be modified with lowcost upgrade kits to provide uniformly higher accuracy over the entire transponder coverage range.
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Dorth, Mélodie Kern Sarubo. "Proposta de classificação de linhas de base obtidas com dados GPS, à luz de árvore de decisão." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18143/tde-13012011-142819/.

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Ao se efetuar levantamentos utilizando a tecnologia GNSS, o processamento desses dados, bem como uma análise dos fatores oriundos dos processamentos e a correta interpretação dos resultados obtidos, consiste em fator primordial para se definir a qualidade de um levantamento. Contudo, os resultados estatísticos fornecidos pelos softwares comerciais após o processamento e ajustamento dos dados, apesar de garantir maior confiabilidade aos levantamentos, não fornecem a acurácia das coordenadas encontradas, apresentando apenas a sua precisão. Assim, este trabalho tem por objetivo final, fornecer uma tabela onde seja possível, através de uma comparação dos resultados oriundos dos processamentos, classificar a acurácia dos mesmos. Para tanto, foram efetuados os processamentos e ajustamentos de dados inerentes as quatro estações do ano, durante os anos de 2006, 2007 e 2008, e após adequada análise dos mesmos, foi implementada uma Tabela de Acurácia Recomendada, onde os profissionais da área de mensuração poderão, através de uma comparação entre os relatórios de processamento fornecidos e os itens da referida tabela, efetuar a classificação da acurácia dos trabalhos de interesse.
When making surveys using GNSS technology, the processing of these data, as well as an analysis of the factors resulting from the processing and the correct interpretation of results, is to prime factor for defining the quality of a survey. However, the statistics provided by commercial software after processing and adjustment of the data, while ensuring high reliability of surveys, do not provide the accuracy of the coordinates found, showing only its precision. This paper aims to provide a table where possible, by comparing the results from the processing, The classification accuracy of them. To do so, we made adjustments and the processing of data relating the four seasons, during the years 2006, 2007 and 2008, and after proper analysis of the same purpose, a Table of Accuracy Recommended where professionals in the area of measurement may, through a comparison between the reports provided and processing the items of the tariff, to perform the classification accuracy of the work of interest.
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Denker, Phillip Michael. "Tracking military maneuver training disturbance with low cost GPS devices." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/16870.

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Master of Science
Department of Biological and Agricultural Engineering
Stacy L. Hutchinson
Military training lands are a vital resource for national security and provide crucial habitat for a number of threatened and endangered species. Military land managers must manage the land in accordance with federal environmental policy and regulation, while simultaneously providing the lands needed for training military forces. Off road maneuver training can cause significant environmental damage including removal of vegetation, compaction of soils, increased erosion, loss of habitat, and degradation of the landscape to a point of not being useful for continued military training. Various techniques have been developed to help the military land managers determine a sustainable training level for the landscape. Many of these techniques have limitations in the spatial resolution of data collected and the ability to provide timely and accurate assessments of training disturbance. Advancements in GPS and GIS technology over the past two decades have shown the potential to fill this knowledge gap. In this study low cost civilian off the shelf (COTS) GPS devices were accuracy tested to determine their capability to provide reliable and accurate military vehicle locations during training (1.93 m CEP, 4.625m 2dRMS). The GPS data collected from COTS devices on three battalion training exercises at Fort Riley, KS were processed in a GIS and statistically analyzed to compare and contrast several off road maneuver metrics (speed, turning radius, distance traveled) by vehicle type tracked, and by platoon in order to determine if units or vehicle types could reliably explain the variation in these metrics. Lastly, a method of mapping the relative environmental disturbance was developed and mapped for the same data sets. Wheel sinkage was used as a measure of disturbance, it was calculated at each GPS point based on vehicle type and soil conditions then mapped in using a fishnet grid for Fort Riley, Kansas.
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Moraes, Alarico Valls de. "ANÁLISE DA QUALIDADE DE RESULTADOS GPS EM PROGRAMAS COMERCIAIS." Universidade Federal de Santa Maria, 2005. http://repositorio.ufsm.br/handle/1/9493.

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The Brazilian technician-scientific community that dedicates to the surveying is living a new time with the normatization of the technical parameters for reference of the geodesic surveys to Cadastro Nacional de Imóveis Rurais according to Brazilian Law 10.267/2001. The objective of this work is to analyse by means of the statistical parameters the quality of the survey data with GPS-receivers and post-processed in the softwares present in the market. Amongst the analysed parameters, the most important is the standard deviation of the coordinates, because it is the measure for the precision and it is an composition element of the accuracy, that indicate the result quality. The results presented by commercial softwares are compared with the official data of the State Landmark GPS network that are information supplied for the Instituto Brasileiro de Geografia e Estatística (IBGE). Also this work contribute for the relation user-manufacturer approaching them thus first when manipulating the programs get greater information availability how much to the applied methodology to give the processing results. By means of the fundamental univariate and multivariate Statistic concepts, this work give an analysis of as the commercial softwares are processing GPS data and also inform which the necessary minimum data that the softwares must supply to the user in order to give the estimated statistical parameters that are an indication the quality of each geodetic survey.
A comunidade técnico-científica brasileira que se dedica à mensuração está vivendo uma nova época com a normatização de parâmetros técnicos para levantamentos geodésicos destinados ao Cadastro Nacional de Imóveis Rurais de acordo com a Lei 10.267/2001. O objetivo desta dissertação é analisar por meio de parâmetros estatísticos estimados a qualidade dos dados oriundos de levantamentos com receptores GPS e pós-processados em programas computacionais presentes no mercado. Dentre os parâmetros estatísticos analisados, o mais importante é o desvio padrão das coordenadas, porque ele é a medida da precisão e compõe a medida da acurácia que exprimem a qualidade dos resultados. Os resultados apresentados pelos programas comerciais são comparados com dados oficiais da Rede Estadual de Marcos GPS que são informações fornecidas pelo Instituto Brasileiro de Geografia e Estatística (IBGE). Este trabalho também contribui para a relação usuário-fabricante aproximando-os, entre si, de maneira que o primeiro ao manipular os programas obtenha maior disponibilidade de informações quanto à metodologia aplicada para obter os resultados do processamento. Por meio dos conceitos fundamentais da Estatística univariada e multivariada, este trabalho fornece uma análise de como os programas comerciais estão processando os dados GPS e informa, também, quais os dados mínimos necessários que os programas computacionais devem fornecer ao usuário para que este obtenha os parâmetros estatísticos estimados indicadores da qualidade para cada levantamento geodésico.
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35

Smith, Nathan Earl. "The use of the Global Positioning System (GPS) on an attack aircraft to improve altitude accuracy during weapons delivery." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/49940.

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36

Ashraf, El-kutb Mousa. "Characteristics of Wet Tropospheric Delay Deduced from Water Vapor Radiometer Data and Their Implications for GPS Baseline Solution Accuracy." 京都大学 (Kyoto University), 1997. http://hdl.handle.net/2433/202445.

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37

Lee, Jaesup. "Comparison of GPS-Equipped Vehicles and Its Archived Data for the Estimation of Freeway Speeds." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14549.

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Video image detection system (VDS) equipment provides real-time traffic data for monitored highways directly to the traffic management center (TMC) of the Georgia Department of Transportation. However, at any given time, approximately 30 to 35% of the 1,600 camera stations (STNs) fail to work properly. The main reasons for malfunctions in the VDS system include long term road construction activity and operational limitations. Thus, providing alternative data sources for offline VDS stations and developing tools that can help detect problems with VDS stations can facilitate the successful operation of the TMC. To estimate the travel speed of non-working STNs, this research examined global positioning system (GPS) data from vehicles using the ATMS-monitored freeway system as a potential alternative measure to VDS. The goal of this study is to compare VDS speed data for the estimation of the travel speed on freeways with GPS-equipped vehicle trip data, and to assess the differences between these measurements as a potential function of traffic and roadway conditions, environmental, conditions, and driver/vehicle characteristics. The difference between GPS and VDS speeds is affected by various factors such as congestion level (expressed as level of service), onroad truck percentage, facility design (number of lanes and freeway sub-type), posted speed limit, weather, daylight, and time of day. The relationship between monitored speed difference and congestion level was particularly large and was observed to interact with most other factors. Classification and regression tree (CART) analysis results indicated that driver age was the most relevant variable in explaining variation for the southbound of freeway dataset and freeway sub-type, speed limit, driver age, and number of lane were the most influential variables for the northbound of freeway dataset. The combination of several variables had significant contribution in the reduction of the deviation for both the northbound and the southbound dataset. Although this study identifies potential relationships between speed difference and various factors, the results of the CART analysis should be considered with the driver sample size to yield statistically significant results. Expanded sampling with larger number of drivers would enrich this study results.
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Itame, Otávio Yassuo 1956. "Avaliação do posicionamento plano-altimétrico com receptor gps em diferentes tipos de uso do solo /." Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/101877.

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Orientador: Zacarias Xavier de Barros
Banca: José Milton Arana
Banca: Osmar Delmanto Junior
Banca: Lincoln Gering Cardoso
Banca: Vilmar Antonio Rodrigues
Resumo: Neste trabalho, foram realizados levantamentos topográficos para a avaliação do efeito da cobertura vegetal, na recepção de sinais GPS, para obtenção de posicionamento tri-dimensional, considerando os estudos realizados em diferentes tipos de uso do solo. Vértices foram implantados em diferentes tipos de uso do solo; em área com pastagem, com plantação de seringueiras e com eucaliptos, e as suas posições determinadas com estação total, nivelamento geométrico e com receptores GPS. Na avaliação do posicionamento altimétrico adotou-se como valores de referência os desníveis determinados com o nivelamento geométrico para avaliação dos dados obtidos com receptores GPS. As coordenadas planimétricas obtidas com receptores GPS foram analisadas utilizando-se com valores de referência os dados obtidos com a estação total. No levantamento topográfico com estação total foram adotadas as prescrições estabelecidas nas Normas da Associação Brasileira de Normas Técnicas (ABNT) NBR 13.133, Execução de Levantamentos Topográficos, para poligonais do tipo IVP. Foi realizada a análise de exatidão e de precisão do posicionamento tridimensional, adotando como padrão a NBR 13133 da ABNT para a classe do levantamento executado. Para aplicações do GPS na altimetria há necessidade do conhecimento da ondulação geoidal (N), que neste trabalho, para a sua determinação foram coletados dados com receptor na referência de nível (RN). Os resultados obtidos indicam que cuidados especiais devem ser tomados nos levantamentos com receptores GPS em áreas com cobetura vegetal, pois estas interferem na propagação das ondas eletromagnéticas provenientes dos satélites podendo inviabilizar o posicionamento.
In this work, topographic surveys were carried out in order to evaluate the effect of vegetal cover, on the reception of GPS signals, for 3D positioning, considering studies to be made in different types of land use. Points were set up on different types of land use, in areas containing grass, rubber trees and eucalyptus, which had their positions defined using a total station, geometric leveling and GPS receivers In the evaluation of height positioning it was adopted as reference values the height differences determined by geometric levelling in order to evaluate data obtained through GPS receivers. Planimetric coordinates obtained by using GPS receivers were analysed using as reference values the data obtained using a total station. During the topographic survey using a total station the recommendations set up by the Brazilian Association for Technical Rules (ABNT) NBR 13.133, regarding the execution of topographic surveys, for transverses of type IVP. Accuracy and precision analysis was made on the 3D positioning, also considering ABNT NBR 13.133, for the class of topographic survey which was carried out. In order to apply GPS on height positiong it is necessary to know the geoidal ondulation (N) and, in this work, N was computed based upon data acquired employing receivers at the level reference (RN). The results obtained indicate that special care must be taken during the surveys carried out with the use of GPS receivers on areas with vegetal cover, because it causes interference in the propagation of electromagnetic waves from the satellite which can even make the positioning become unviable.
Doutor
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39

Legru, Benoît. "Mesure de déformation par combinaison de techniques géodésiques : Auscultation par GPS et topométrie." Phd thesis, Conservatoire national des arts et metiers - CNAM, 2011. http://tel.archives-ouvertes.fr/tel-00736511.

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La Terre est une planète en constante évolution et sa surface ne cesse de se transformer. Ses déformations soulèvent des questionnements. Depuis plusieurs années, le L2G de l'ESGT s'intéresse à l'étude des déformations par inter comparaison de techniques. Il dispose en cela de différents procédés de mesure. Puis au fil du temps, le laboratoire s'interroge sur l'intérêt de réaliser une combinaison entre différentes techniques de mesure afin d'observer des déformations fines et précises (quelques millimètres).L'objectif de cette thèse est de démontrer l'intérêt de combiner des mesures GNSS et des mesures topométriques, celles-ci semblant être les plus utilisées, et de les concrétiser. Les résultats présentés sont basés sur des simulations et sur des campagnes de mesures combinées des techniques de GNSS et de topométrie effectuée sur un réseau test d'une étendue locale. Les calculs évoluent en fonction de la distance de la ligne de base et en modifiant les durées de sessions de mesures. Nous montrons qu'une combinaison par cumul des équations normales améliore la précision du positionnement non seulement par rapport à l'utilisation de chaque technique séparée, mais également par rapport aux méthodes classiques basées sur la combinaison des coordonnées issues des techniques de GNSS et de topométrie.
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40

Jurajda, David. "Modul kombinované globální satelitní navigace." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220291.

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The thesis objective is design of methodology focused on accuracy measurement in field of GPS/GLONASS receivers. Text is devided into five main parts. The first one is focused on GNSS technology. Second one deals with used coordinate systems and map projections (ETRS89, WGS84, UTM, Gauss-Krüger). Next part discusses statistical methods. Part four is focused on hardware. Then the final part describes experiment realization and obtained data analysis.
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41

Dickman, Jeff. "Single Platform Relative Positioning for Sensor Stabilization." Ohio University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1210187565.

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42

Itame, Otávio Yassuo [UNESP]. "Avaliação do posicionamento plano-altimétrico com receptor gps em diferentes tipos de uso do solo." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/101877.

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Neste trabalho, foram realizados levantamentos topográficos para a avaliação do efeito da cobertura vegetal, na recepção de sinais GPS, para obtenção de posicionamento tri-dimensional, considerando os estudos realizados em diferentes tipos de uso do solo. Vértices foram implantados em diferentes tipos de uso do solo; em área com pastagem, com plantação de seringueiras e com eucaliptos, e as suas posições determinadas com estação total, nivelamento geométrico e com receptores GPS. Na avaliação do posicionamento altimétrico adotou-se como valores de referência os desníveis determinados com o nivelamento geométrico para avaliação dos dados obtidos com receptores GPS. As coordenadas planimétricas obtidas com receptores GPS foram analisadas utilizando-se com valores de referência os dados obtidos com a estação total. No levantamento topográfico com estação total foram adotadas as prescrições estabelecidas nas Normas da Associação Brasileira de Normas Técnicas (ABNT) NBR 13.133, Execução de Levantamentos Topográficos, para poligonais do tipo IVP. Foi realizada a análise de exatidão e de precisão do posicionamento tridimensional, adotando como padrão a NBR 13133 da ABNT para a classe do levantamento executado. Para aplicações do GPS na altimetria há necessidade do conhecimento da ondulação geoidal (N), que neste trabalho, para a sua determinação foram coletados dados com receptor na referência de nível (RN). Os resultados obtidos indicam que cuidados especiais devem ser tomados nos levantamentos com receptores GPS em áreas com cobetura vegetal, pois estas interferem na propagação das ondas eletromagnéticas provenientes dos satélites podendo inviabilizar o posicionamento.
In this work, topographic surveys were carried out in order to evaluate the effect of vegetal cover, on the reception of GPS signals, for 3D positioning, considering studies to be made in different types of land use. Points were set up on different types of land use, in areas containing grass, rubber trees and eucalyptus, which had their positions defined using a total station, geometric leveling and GPS receivers In the evaluation of height positioning it was adopted as reference values the height differences determined by geometric levelling in order to evaluate data obtained through GPS receivers. Planimetric coordinates obtained by using GPS receivers were analysed using as reference values the data obtained using a total station. During the topographic survey using a total station the recommendations set up by the Brazilian Association for Technical Rules (ABNT) NBR 13.133, regarding the execution of topographic surveys, for transverses of type IVP. Accuracy and precision analysis was made on the 3D positioning, also considering ABNT NBR 13.133, for the class of topographic survey which was carried out. In order to apply GPS on height positiong it is necessary to know the geoidal ondulation (N) and, in this work, N was computed based upon data acquired employing receivers at the level reference (RN). The results obtained indicate that special care must be taken during the surveys carried out with the use of GPS receivers on areas with vegetal cover, because it causes interference in the propagation of electromagnetic waves from the satellite which can even make the positioning become unviable.
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43

Neto, João Olympio de Araújo. "Análise da precisão e acurácia de pontos georreferenciados com a técnica do código suavizado pela fase da portadora utilizando GPS de simples freqüência." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-29052007-170329/.

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A presente dissertação teve como finalidade avaliar a precisão e a discrepância das coordenadas (acurácia) obtidas por meio das observações GPS, no modo estático rápido, medidas com receptores de uma freqüência, empregando-se a técnica de suavização do código C/A pela fase da portadora para diferentes comprimentos de linha base (20, 50, 75, 100, 150, 200 e 300 Km), a partir da estação de monitoramento contínuo da EESC/USP. Essa técnica obteve boa repercussão no Brasil, a partir do momento em que foi permitida sua utilização para fins de georreferenciamento de imóveis rurais, conforme a norma técnica do INCRA, que permite a utilização da suavização do código pela fase da portadora, desde que esta apresente acurácia com valores iguais ou inferiores a 50 cm. Atualmente, trabalhos com tal técnica estão sendo desenvolvidos e aceitos para compor o banco de dados do cadastro rural nacional. Pelos resultados obtidos nesta dissertação, foi possível avaliar que a aplicação dessa técnica não atende à exigência requerida em 100% das medições e, ao mesmo tempo, verificar a diferença entre a precisão do pós-processamento, indicada pelos softwares comerciais e a acurácia dos pontos medidos comparados com os pontos de controle estabelecidos para esse fim.
The present dissertation has as objective to evaluate precision and discrepancies of coordinates (accuracy) obtained through GPS observations, in a rapid static method, measured by single frequency, which applies carrier-smoothed-code for different baseline length (20, 50, 75, 100, 150, 200 and 300 km), since continuous monitoring station from EESC/USP. This technique obtained a good repercussion in Brazil, since when its use was legitimate in rural property georeferencing, according to INCRA\'s norma técnica (technical rule), which allows the use of carrier-smoothed-code in view of the fact that presents accuracy with equal or inferior values to 50 cm. Currently, works using such technique are developed and accepted in order to compound database of national rural survey in Brazil. Based on the obtained results it was possible to evaluate that the technique does not guaranteed to requested requirement in 100% of measurements, and at the same time to verify the difference between post-processing precision, indicated by commercial software, as well as measured point accuracy compared with points established for this purposed.
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44

Granberg, Petter, and Roger Li. "Technical Verification and Validation of ADS-B/VDL Mode 4 for En-route Airspace and Major Terminal Areas." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-67423.

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This report is a technical verification and validation of Automatic Dependent Surveillance – Broadcast (ADS-B) over Very High Frequency Data Link Mode 4 (VDL Mode 4) for the use as surveillance in terminal areas and en-route airspace in non-radar areas. The main objective is to verify that ADS-B/VDL Mode 4 fulfils the technical requirements for an implementation at Kiruna airport, Sweden. Comparison has been made to the current requirements for Secondary Surveillance Radar (SSR). The work in this report has been conducted in three phases: preliminary study, tests and verification and validation. During the preliminary study documents primarily from EUROCONTROL and ICAO were used to find out which requirements that were applicable. The next part consisted of both practical tests and theoretical verification of the VDL Mode 4 performance. Finally the results from the tests were validated and put together in this report. Main conclusion from this report is that ADS-B/VDL Mode 4 fulfils the corresponding SSR requirements. Therefore ADS-B/VDL Mode 4 should be able to serve as primary mean for surveillance in non-radar areas. The results from this report will constitute a part of the technical subset of future safety case for ADS-B in non-radar areas. The complete safety case will be used to authorize ADS-B/VDL Mode 4 in non-radar airspace, both in Sweden and internationally.
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45

Ptáček, Pavel. "Výkonnost služby GNSS pro aplikace prostorové navigace civilního letectví v ČR." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-234234.

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The dissertation deals with the assessment of navigation performance of GPS/EGNOS system in user position domain. Examination is based on a static signal in space monitoring and evaluation campaign to assess the ability to provide sufficient performance for new navigation procedures. GPS/EGNOS system is the first primary navigation system to be used in the airspace of Czech Republic. The first part describes the benefits of using new procedures, summarizes navigation development and current status. The second part defines components of GPS/EGNOS primary navigation system being analysed and its characteristics with the potential impact on the quality of approach navigation services to be provided and ensured by EGNOS. Subsequently, the methodology for critical evaluation of GPS/EGNOS signal in space navigation performance in position domain to be monitored by of air traffic services was formulated, using new methods for investigation of accuracy, integrity and continuity with the focus on final approach procedures. Simultaneously supporting software for data analysis against performance requirements in position domain was designed. Based on campaigns of static experimental measurements and detailed analysis of combined GPS/EGNOS performance against the demands, the level of performance is analysed, the findings are presented and conclusions are made. In the last part, the usage of permanent geodetic stations for regular evaluation of GNSS performance for civil aviation purposes is designed and verified, and the conclusions based on navigation performance evaluation of observations from all selected station in the Czech Republic.
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46

Bennett, Benjamin. "Accurate Distance Calculation Using GPS While Performing Low Speed Activity." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23827.

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In the last 10 years GPS technology has become widely available due to the proliferation of smart devices with GPS capability. GPS was introduced as a method to assist in location and navigation and is still the most common use for this technology today. Many may not consider that GPS can be used for a variety of different purposes. GPS technology can be used to calculate the distance of activity (running, walking, biking etc.) to build applications to promote exercise and a healthy lifestyle. Calculating this distance accurately is challenging due to the amount of error in GPS location measurements and the low speed of many activities. In this thesis I present methods of calculating distance traveled that reduces this error to produce an accurate distance calculation. I also present an application that uses this distance calculation to help promote children to become more active.
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47

Smith, Clinton James. "High-accuracy laser spectrometers for wireless trace-gas sensor networks." Thesis, Princeton University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3604506.

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The subject of this dissertation is the development of a wireless sensor network composed of instruments which employ both VCSELs and QCLs for accurate, highly sensitive, and reliable long-term monitoring of environmental trace-gases. The dissertation focuses on the development of low-power instruments and calibration methods that ensure the reliability of long-term measurements.

First the field deployment of a low-power, portable, wireless laser spectroscopic sensor node for atmospheric CO2 monitoring is demonstrated. The sensor node shows 0.14 ppmv Hz-1/2 1σ measurement sensitivity of CO2 concentration changes. It was first used to measure top-soil respiration rates in the laboratory and on forest floors in the field.

Then after a long-term field deployment to further assess instrument performance, new design solutions were implemented to improve fringe-limited precision of the nodes to 4-7 ppmv against a 400 ppmv CO2 background, making their performance comparable to higher power consuming commercial trace-gas analyzers. Three optimized nodes were then deployed into mixed landscapes as part of a solar powered CO2 monitoring wireless network. The three node network monitored CO2 in a grassy/woody courtyard, on top of the roof of an engineering building, and next to a road in the Princeton area. These works show that ultra-low powered VCSEL based sensor nodes can be placed in off-the-grid environments for autonomous distributed geographic monitoring of trace-gases in a manner which is impossible with current commercial techniques.

Next, this dissertation covers two techniques that were developed for the real-time calibration of laser-based trace-gas measurements. The first technique used an in-line reference gas cell and employed wavelength modulation spectroscopy (WMS) at higher harmonics to simultaneously probe the sample and reference spectra. The second technique used a revolving in-line reference cell to suppress background and other non-spectroscopic signals. These techniques were designed for eventual inclusion as a real-time calibration source for field deployable trace-gas sensors and wireless sensor networks.

Finally, this dissertation demonstrates the use of the CW injection current into a VCSEL in an external cavity configuration to tune the cavity emission's self-oscillation frequency and show through simulation and experiment that the tuning is dependent on VCSEL birefringence change.

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48

Gervais, Renaud. "Towards High-Accuracy Augmented Reality GIS for Architecture and Geo-Engineering." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28989/28989.pdf.

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L’architecture et la géo-ingénierie sont des domaines où les professionnels doivent prendre des décisions critiques. Ceux-ci requièrent des outils de haute précision pour les assister dans leurs tâches quotidiennes. La Réalité Augmentée (RA) présente un excellent potentiel pour ces professionnels en leur permettant de faciliter l’association des plans 2D/3D représentatifs des ouvrages sur lesquels ils doivent intervenir, avec leur perception de ces ouvrages dans la réalité. Les outils de visualisation s’appuyant sur la RA permettent d’effectuer ce recalage entre modélisation spatiale et réalité dans le champ de vue de l’usager. Cependant, ces systèmes de RA nécessitent des solutions de positionnement en temps réel de très haute précision. Ce n’est pas chose facile, spécialement dans les environnements urbains ou sur les sites de construction. Ce projet propose donc d’investiguer les principaux défis que présente un système de RA haute précision basé sur les panoramas omnidirectionels.
Architecture and geo-engineering are application domains where professionals need to take critical decisions. These professionals require high-precision tools to assist them in their daily decision taking process. Augmented Reality (AR) shows great potential to allow easier association between the abstract 2D drawings and 3D models representing infrastructure under reviewing and the actual perception of these objects in the reality. The different visualization tools based on AR allow to overlay the virtual models and the reality in the field of view of the user. However, the architecture and geo-engineering context requires high-accuracy and real-time positioning from these AR systems. This is not a trivial task, especially in urban environments or on construction sites where the surroundings may be crowded and highly dynamic. This project investigates the accuracy requirements of mobile AR GIS as well as the main challenges to address when tackling high-accuracy AR based on omnidirectional panoramas.
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49

Patil, Prashant Vithal. "Commissioning of a magnetic suspension densitometer for high-accuracy density measurements of natural gas mixtures." [College Station, Tex. : Texas A&M University, 2005. http://hdl.handle.net/1969.1/ETD-TAMU-1003.

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50

COSTA, JUNIOR NELSON V. da. "Caracterizacao e otimizacao analitica na determinacao de trialometanos em aguas potaveis por purga e armadilha acoplada a cromatografia a gas." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9521.

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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