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  1. Aplicativo Web para la Fusión de Imágenes Satelitales

    Directory of Open Access Journals (Sweden)

    Javier Medina

    2013-06-01

    Full Text Available En este artículo se implementa un servicio en la Web que ofrece la posibilidad de realizar la fusión de imágenes de satélite. A lo largo del artículo tres temáticas importantes son abordadas. La primera temática corresponde al servicio Web, éste servicio es implementado usando software libre, donde el usuario puede realizar una solicitud del servicio de fusión. La segunda temática se ocupa del análisis de la transformada rápida de Wavelet haar (TRWH. La última temática detalla la metodología, para realizar la fusión de imágenes usando la TRWH. Con el fin de determinar la eficiencia de la TRWH, cinco Wavelets diferentes fueron implementadas para fusionar el mismo par de imágenes satelitales. Las imágenes resultantes fueron evaluadas tanto en la calidad espacial como espectral a través de cuatro índices. Los mejores resultados de la evaluación fueron obtenidos con la TRWH la cual preserva la riqueza espectral y mejora su calidad espacial

  2. VELOCITY AND GRAVITATIONAL EFFECTS ON GPS SATELLITES: AN OUTLINE OF EARLY PREDICTION AND DETECTION OF STRONG EARTHQUAKES EFECTOS DE VELOCIDAD Y DE GRAVITACIÓN EN GPS SATELITALES: UN ESQUEMA PARA LA PREDICCIÓN Y DETECCIÓN TEMPRANA DE FUERTES TERREMOTOS

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    H Torres-Silva

    2010-12-01

    Full Text Available Today, the global navigation satellite systems, GPS used as global positioning systems, are based on a gravitational model and hence they are only operative when several relativistic effects are taken into account. The most important relativistic effects (to order 1/c² are: the Doppler red shift of second order, due to the motion of the satellite (special relativity and the Einstein gravitational blue shift effect of the satellite clock frequency (equivalence principle of general relativity. Both of these effects can be treated at a basic level, making for an appealing application of relativity to every life. This paper examines the significant effects that must be taken into account in the design and operation of systems GPS without resorting to the theory of special and general relativity, yielding the same results for these systems, where one of the effects can be treated with the time contraction approach proposed here and the other using the Newton's theory as an approximation of the General Relativity. This approach allow us to propose an outline of early prediction and detection on strong earthquake phenomena.Hoy en día, los sistemas de navegación global por satélite, GPS utilizados como sistemas de posicionamiento global, se basan en un modelo gravitacional y por lo tanto solo son operativos cuando varios efectos relativistas son tenidos en cuenta. Los efectos relativistas más importantes (hasta el orden 1/c² son: el desplazamiento Doppler al rojo de segundo orden, debido al movimiento del satélite (la relatividad especial y el efecto gravitacional de Einstein corrimiento al azul de la frecuencia de reloj del satélite (principio de equivalencia de la relatividad general. Ambos efectos pueden ser tratados en un nivel básico, apelando a la relatividad del día a día. Este artículo examina los efectos significativos que deben tenerse en cuenta en la operación de sistemas de GPS sin tener que recurrir a las teorías de la

  3. SERVICIO GRID PARA LA CLASIFICACIÓN NO SUPERVISADA DE IMÁGENES SATELITALES UTILIZANDO AUTÓMATAS CELULARES

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    Germán Amézquita Becerra

    2009-01-01

    Full Text Available Este artículo describe el proceso investigativo por el cual se exploró y puso en práctica la tecnología Grid como elemento promotor del proceso de clasificación no supervisada de imágenes satelitales LANDSAT; se ha implementado un servicio Grid que aplica autómatas celulares como técnica de inteligencia artificial. Las anteriores tareas se han logrado estableciendo una infraestructura Grid y un modelo de implementación que da soporte al servicio Grid. El modelo del servicio visualiza el contenedor de servicios y el contenedor de "portlet", los cuales se integran para formar tanto el cliente como el servidor. El autómata celular utilizado, esta definido en vecindarios de dos dimensiones y se establece la proyección de los niveles digitales de tres de las bandas de la imagen y la ubicación de cada una de ellas sobre el vecindario definido. El algoritmo se basa en reglas de transición que generan modificaciones a los vecindarios hasta obtener las categorías deseadas. Como resultado del proceso de clasificación se genera una nueva imagen en la cual se expresan las categorías en valores de 0 a 255 y se establece falso color para visualizar los resultados obtenidos.

  4. Sistemas satelitales

    OpenAIRE

    Osorio Avila, Fernando Arturo; Andrade Sigüenza, Edwin Ricardo

    2006-01-01

    En los últimos años, la tecnología satelital ha recobrado gran importancia en el terreno de las comunicaciones. El desarrollo de la fibra óptica parecía que iba a obstaculizar la evolución de los satélites artificiales de comunicación, como consecuencia de sus características de transmisión (Velocidad, Capacidad, Durabilidad…), pero pocos pensaron en los diversos retos que debía enfrentar esta tecnología de comunicación (geográficos, climáticos, y sobretodo financieros). Para cumplir el pr...

  5. Utilización de imágenes satelitales para el estudio de la distribución térmica en distintas coberturas del suelo de la ciudad de Bahía Blanca (Argentina

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    F. Ferrelli

    2015-12-01

    Full Text Available El estudio del clima urbano es relevante para conocer el ambiente donde habita la mayor parte de la población. Las ciudades presentan sectores que incluyen estructuras edilicias, espacios verdes, suelos al descubierto, tránsito vehicular, necesidades calóricas de la ciudad y diferentes coberturas de sombras. Actualmente, el cambio climático y sus efectos sobre las ciudades son temas de gran interés científico. Son escasas las investigaciones que interpretan los cambios térmicos que se producen en el interior de las ciudades debido a la densificación de los edificios y como consecuencia de la variabilidad climática. Por tal motivo, el objetivo de este trabajo fue analizar el comportamiento de la Temperatura de Superficie Terrestre (TST y su relación con las distintas coberturas del suelo en la ciudad de Bahía Blanca, Argentina. Para ello, se analizaron imágenes satelitales Landsat 5 TM y 7 ETM+ con el método monocanal. Además, se realizó un mapa de coberturas del suelo mediante interpretación visual de imágenes satelitales validado por intervención empírica. Posteriormente, se relacionaron los datos de TST con las coberturas del suelo. En el centro de la ciudad, la TST presentó variaciones espaciales heterogéneas según las estaciones del año y las sombras generadas por los edificios. Los mayores valores de TST se localizaron en la periferia (45,1°C y en urbano muy disperso (46°C y el menor en el centro de la ciudad (2°C. Las distintas coberturas del suelo generaron menores fluctuaciones de TST en invierno (>5°C y las mayores en verano (entre 15 y 25°C.

  6. Minería de datos con información de contexto para la clasificación de imágenes satelitales / Data mining with context information for satellite image classifi cation

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    Jesús A. González

    2008-09-01

    Full Text Available En este artículo se presenta un esquema de clasifi cación multi-modelos para imágenes satelitales apoyado con información de contexto conel que se mejora la precisión de una pre-clasifi cación obtenida conalgoritmos paramétricos. El nuevo esquema utiliza una red semántica como representación de conocimiento que almacena patrones creados con un ensamble de árboles de decisión (alimentado con características espectrales, de textura y geométricas para describir a las regiones de interés y por otro lado patrones espaciales creados a partir de unarepresentación basada en grafos (con información de contexto a partir de relaciones espaciales entre las regiones de interés. Los resultados experimentales muestran que el esquema de clasifi cación propuesto mejora la precisión de la pre-clasifi cación de los algoritmos paramétricosal utilizar información de contexto.

  7. IMPLEMENTACIÓN DE UN SERVICIO EN LA WEB –MASHUP– PARA LA FUSIÓN DE IMÁGENES SATELITALES USANDO LA TRANSFORMADA RÁPIDA DE WAVELET HAAR

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    Rubén Medina

    2014-05-01

    Full Text Available En este artículo se implementa un nuevo servicio en la Web que ofrece a los usuarios la posibilidad de realizar la fusión de imágenes de satélite provenientes de diferentes sensores remotos y/o con diferentes resoluciones espaciales. A lo largo del artículo tres temáticas importantes son abordadas. La primera temática corresponde al servicio Web, éste servicio es implementado usando software libre y cuenta con una sencilla interfaz donde el usuario puede interactuar y principalmente puede realizar una solicitud del servicio de fusión. Adicionalmente, en la aplicación Web se desarrolló un módulo que permite obtener datos georreferenciados de diferentes fuentes externas para crear un nuevo servicio (Mashup a través de las API’s, de manera rápida y fácil utilizando OpenStreetMaps. La segunda temática se ocupa del análisis de la transformada rápida de wavelet haar (TRWH, estos conceptos matemáticos se abordan a partir de un ejemplo usando una matriz que se descompone en coeficientes de detalle y de aproximación de segundo nivel. La última temática detalla la metodología propuesta, paso a paso, para realizar la fusión de imágenes usando la TRWH. Igualmente con el fin de determinar la eficiencia de la TRWH cinco wavelets diferentes fueron implementadas en Matlab para fusionar el mismo par de imágenes satelitales. Las imágenes resultantes fueron evaluadas tanto en la calidad espacial como en la espectral a través de cuatro índices. Los mejores resultados de la evaluación fueron obtenidos con la TRWH la cual preserva la riqueza espectral de la imagen multiespectral original y mejora su calidad espacial.

  8. Mapa de riesgo de temperaturas extremas frías para el sur de la provincia de Buenos Aires usando datos satelitales y de superficie Frost risk map for the south of Buenos Aires province using satellite and surface data

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    Roberto De Ruyver

    2012-06-01

    Full Text Available Cerca del 40 % del área sembrada con trigo en Argentina se concentra en el sur de la provincia de Buenos Aires. Los eventos frecuentes de temperaturas extremas frías en la segunda quincena de octubre, coincidentes con un momento fenológico sensible del trigo, provocan daños de importancia en el cultivo. El presente trabajo tiene como objetivo proveer mapas de riesgo de temperaturas extremas frías para el período sensible del cultivo de trigo en esa región. Se utilizó información de los canales 3, 4 y 5 del satélite NOAA de 1,09 km² de resolución espacial, obtenidas en el Instituto de Clima y Agua del INTA-Castelar entre 2005 y 2008, y datos diarios de temperaturas mínimas del período 1961-2008 de 13 estaciones de superficie del Servicio Meteorológico Nacional (SMN y del Instituto Nacional de Tecnología Agropecuaria (INTA. Los resultados muestran que las áreas de mayor riesgo son aquellas que combinan menor altura sobre el nivel del mar y al mismo tiempo mayor distancia al mismo. Esta metodología puede ser extendida a otros cultivos y a otras regiones. Este tipo de análisis constituye una herramienta que puede ser útil en tareas de planificación tanto a nivel estatal como privado.Cold temperature can cause severe damage in crops when a cold front irruption occurs. This is especially true in some specific periods on the growing crops mainly during spring. This work presents frost risk maps for wheat. The region selected was the south of Buenos Aires province in Argentina. Wheat covers almost 2,2 million ha in south Buenos Aires area which represents 40% of the total wheat cultivated in Argentina At the same time, south Buenos Aires area suffers the biggest damage on wheat because of frost during spring time. The study was carried out based on channels 3, 4 and 5 of NOAA satellite images (1,09 km² spatial resolution. Images from 2005 to 2008 were available. Minimum daily temperatures from "Servicio Meteorológico Nacional

  9. Equipamento microprocessado para geração de sinal de correção diferencial, em tempo real, para GPS Microprocessor-based equipment for real time generation of differential GPS correction signal

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    Thales C. B. Lima

    2006-08-01

    Full Text Available Este trabalho apresenta o desenvolvimento de um equipamento microprocessado, de baixo custo, para geração de sinal de correção diferencial para GPS, em tempo real, e configuração e supervisão do receptor GPS base. O equipamento desenvolvido possui um microcontrolador dedicado, display alfanumérico, teclado multifunção para configuração e operação do sistema e interfaces de comunicação. O circuito eletrônico do equipamento tem a função de receber as informações do GPS base e interpretá-las, transformando-as numa sentença no protocolo RTCM SC-104. O software do microcontrolador é responsável pela conversão do sinal recebido pelo GPS base, do formato proprietário para o protocolo RTCM SC-104. A placa processadora principal possui duas interfaces seriais padrão RS-232C. Uma delas tem a função de configuração e leitura das informações geradas pelo receptor GPS base. A outra atua somente como saída, enviando o sinal de correção diferencial. O projeto do equipamento microprocessado mostrou que é possível a construção de uma estação privada para a geração do sinal de correção diferencial, de baixo custo.This work presents the development of low cost microprocessor-based equipment for generation of differential GPS correction signal, in real time, and configuration and supervision of the GPS base. The developed equipment contains a dedicated microcontroller connected to the GPS receiver, alphanumeric display and multifunction keyboard for configuration and operation of the system and communication interfaces. The electronic circuit has the function of receiving the information from GPS base; interpret them, converting the sentence in the RTCM SC-104 protocol. The microcontroller software makes the conversion of the signal received by the GPS base from the specific format to RTCM SC-104 protocol. The processing main board has two serials RS-232C standard interfaces. One of them is used for configuration and

  10. Arquitectura de acoplamiento entre INS/GPS para navegación precisa en trayectorias establecidas

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    Monica Zabala

    2018-05-01

    Full Text Available Se implementa un prototipo basado en tarjetas de desarrollo para el acoplamiento del sistema de navegación inercial con GPS para mejorar la precisión en la navegación sobre una trayectoria. Inicialmente es necesario la calibración de la unidad de medición inercial (IMU mediante un filtro de MADGWICK para que los datos brutos extraídos sean fiables, el acoplamiento de las señales del sistema de posicionamiento global (GPS e IMU se realiza a través de la arquitectura Tight Coupling por medio del Filtro de Kalman con el fin de eliminar errores correlacionados entre sistemas y alcanzar mejor precisión en la solución de navegación generalmente utilizada para aplicaciones en vehículos aéreos no tripulados (UAV. Se desarrolla la aplicación final denominada LJLAB en Matlab, cuya función es procesar y visualizar los datos medidos de ambos sistemas en forma independiente y acopladas al mostrar gráficamente el error en la precisión de posicionamiento que existe entre tecnologías, lo cual es comprobado estadísticamente a través del método experimental ANOVA que calcula el error absoluto entre los puntos reales y los medidos a través del análisis de la media y varianza de los datos observados.

  11. GPS receivers for georeferencing of spatial variability of soil attributes Receptores GPS para georreferenciamento da variabilidade espacial de atributos do solo

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    David L Rosalen

    2011-12-01

    Full Text Available The characterization of the spatial variability of soil attributes is essential to support agricultural practices in a sustainable manner. The use of geostatistics to characterize spatial variability of these attributes, such as soil resistance to penetration (RP and gravimetric soil moisture (GM is now usual practice in precision agriculture. The result of geostatistical analysis is dependent on the sample density and other factors according to the georeferencing methodology used. Thus, this study aimed to compare two methods of georeferencing to characterize the spatial variability of RP and GM as well as the spatial correlation of these variables. Sampling grid of 60 points spaced 20 m was used. For RP measurements, an electronic penetrometer was used and to determine the GM, a Dutch auger (0.0-0.1 m depth was used. The samples were georeferenced using a GPS navigation receiver, Simple Point Positioning (SPP with navigation GPS receiver, and Semi-Kinematic Relative Positioning (SKRP with an L1 geodetic GPS receiver. The results indicated that the georeferencing conducted by PPS did not affect the characterization of spatial variability of RP or GM, neither the spatial structure relationship of these attributes.A caracterização da variabilidade espacial dos atributos do solo é indispensável para subsidiar práticas agrícolas de maneira sustentável. A utilização da geoestatística para caracterizar a variabilidade espacial desses atributos, como a resistência mecânica do solo à penetração (RP e a umidade gravimétrica do solo (UG, é, hoje, prática usual na agricultura de precisão. O resultado da análise geoestatística é dependente da densidade amostral e de outros fatores, como o método de georreferencimento utilizado. Desta forma, o presente trabalho teve como objetivo comparar dois métodos de georreferenciamento para a caracterização da variabilidade espacial da RP e da UG, bem como a correlação espacial dessas vari

  12. Diseño, fabricación y prueba de una antena de parche para GPS en aplicaciones automotrices Diseño, fabricación y prueba de una antena de parche para GPS en aplicaciones automotrices

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    S. V Koshevaya

    2012-02-01

    Full Text Available This work is focused on the development of a prototype patch antenna designed for use asa replacement antenna in automotive Global Positioning Systems (GPS. In simulations andtesting of the prototype, the focus was on the antenna gain. Transmission-reception testingwas done to verify the operation frequency. The prototype was tested with a commercial GPSkit to evaluate its performance as a replacement antenna. Laboratory testing showed that itcomplied with the minimum requirements for both reception and transmission frequencies,while testing on a stationary vehicle showed slight variations when compared to the positiondata obtained using the same kit with its original antenna. In non-stationary testing, positiondeterminations made with the prototype were sufficiently precise for use.Este trabajo se centra en el desarrollo de una antena de parche diseñada para Sistemas de Posicionamiento Global (GPS, con la finalidad de emplearla como antena de reemplazo en aplicaciones automotrices. En las simulaciones y pruebas se pone énfasis en su ganancia. Las pruebas de transmisión-recepción se realizaron para verificar que la frecuencia de operación de la antena fabricada sea la adecuada. Las pruebas con un kit de GPS comercial fueron realizadas para comparar su desempeño como antena de reemplazo. Las pruebas de laboratorio muestran que se cumple con el mínimo requerido para cubrir ambas frecuencias, de recepción y de transmisión, mientras que las pruebas del prototipo, en el techo vehículo sin movimiento, mostraron ligeras variaciones en los datos de posición, comparados con los obtenidos con el kit con su antena original. Las pruebas de viaje mostraron la suficiente precisión en la determinación de la posición para su uso.

  13. Controlador para un Reloj GPS de Referencia en el Protocolo NTP

    Science.gov (United States)

    Hauscarriaga, F.; Bareilles, F. A.

    The synchronization between computers in a local network plays a very important role on enviroments similar to IAR. Calculations for exact time are needed before, during and after an observation. For this purpose the IAR's GNU/Linux Software Development Team implemented a driver inside NTP protocol (an internet standard for time synchronization of computers) for a GPS receiver acquired a few years ago by IAR, which did not have support in such protocol. Today our Institute has a stable and reliable time base synchronized to atomic clocks on board GPS Satellites according to computers's synchronization standard, offering precise time services to all scientific community and particularly to the University of La Plata. FULL TEXT IN SPANISH

  14. GPS, punto de contacto entre la Astronomía y otras disciplinas

    Science.gov (United States)

    Perdomo, R.

    En los primeros años de la pasada década, un grupo de Astrónomos de La Plata iniciaron trabajos de investigación en Geodesia Satelital. En esta presentación se propone repasar sus principales logros y situarlos en el contexto del desarrollo de la disciplina a nivel mundial. Por entonces las aplicaciones prácticas de la disciplina eran indirectas y solo evidentes para los especialistas. Los errores del Posicionamiento Satelital eran de varios metros y en posicionamiento relativo, del orden de medio metro. Estos resultados se lograban al cabo de varios días de medición continuada. En los años siguientes, el sistema GPS alcanzó su nivel operacional y produjo una revolución tanto en lo relacionado con los tiempos de medición como con las precisiones. El grupo de La Plata se desarrolló simultáneamente con GPS, lo que posibilitó su participación actual en diversos temas vigentes: aplicaciones de alta precisión para la materialización de sistemas terrestres de referencia, monitoreo de movimientos de la corteza, contribución con servicios internacionales para la determinación de movimientos tectónicos globales y regionales, monitoreo de la ionósfera a partir de la propagación de las señales, determinación de la ondulación del geoide a escala local, etc. También se generaron muchas aplicaciones prácticas algunas en tiempo real: navegación, apoyo a imágenes aéreas o satelitales, aplicaciones a la agricultura, catastro y ordenamiento territorial, apoyo a relevamientos geofísicos, etc.

  15. El uso de la cartografía e imágenes satelitales como recurso didáctico en la enseñanza

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    Jonathan Andres Manolucos

    2014-06-01

    Full Text Available El presente informe expone el plan de acciones desarrollado y los resultados obtenidos, en el marco de la beca de Iniciación a la Investigación para Estudiantes de Grado y Pregrado de la Universidad Nacional de la Patagonia Austral del alumno Jonathan Manolucos del Profesorado en Geografía. Los objetivos diseñados pretendían revisar el papel de los recursos didácticos (mapas, gráficos, imágenes satelitales, fotografías aéreas y oblicuas en el libro de texto y proponer actividades curriculares a partir de los mapas generados en el marco del proyecto Atlas Geográfico, Ambiental y Satelital de la Provincia de Santa Cruz. Las tecnologías de la información y comunicación (TIC posibilitan la divulgación masiva y el fácil acceso de un gran volumen de información cartográfica y de imágenes satelitales, que facilitan que la sociedad se familiarice con diferentes espacios geográficos. El desarrollo de la Cartografía Digital, la Teledeteccion y los Sistemas de Información Geográfica, agrupados bajo la denominación Tecnologías de Información Geográfica (TIG, permitieron la renovación metodológica y didáctica a la ciencia que debería reflejarse en las formas en las que los docentes abordan el trabajo áulico y las editoriales diseñan los libros de textos. Sin embargo, para los docentes de Enseñanza General Básica el recurso didáctico más utilizado, como instrumento de mediación entre los alumnos y el contenido, sigue siendo el libro de texto. El libro de texto delimita la información de cada disciplina e incluso establece el papel del profesor, su tarea y hasta su forma de evaluar. Los recursos cartográficos suelen aparecer como complemento del texto, sin cumplir con su verdadero rol de instrumento de comunicación o guía de la reflexión frente a diferentes modos de expresión de las variables espaciales.

  16. Búsqueda de Sitios para CTA: Análisis de Datos Satelitales

    Science.gov (United States)

    Suárez, A. E.; Medina, M. C.; Romero, G. E.

    The CTA Consortium has decided to implement a systematic search for sites for the Observatory. This search will be made in two different steps. The first one consists of a general determination of the possible sites on the basis of some very basic selection criteria, such as geographic latitude, altitude and extension of the flat area needed. For those sites passing these criteria, a more intensive characterization should be made, using available satellite data, together with existing ground or air-based measurements. In this work we compare the behavior of different sites analyzing the aerosol content and the total precipitable water vapor, measured by MODIS instrument. FULL TEXT IN SPANISH

  17. GPS Cinemático de precisión para la determinación de puntos en los aeropuertos

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    Jorge Moya Zamora

    2016-03-01

    Full Text Available El establecimiento del apoyo terrestre para la navegación aérea es de vital importancia. De esa manera, el empleo del Sistema de Posicionamiento Global(GPS es el medio más utilizado actualmente, tanto para la navegación de las aeronaves como en la determinación de los puntos de ayuda para dicha navegación, en lo que se refiere a las aproximaciones de las aeronaves, sus aterrizajes y ubicación en los puentes de las terminales aéreas. Estas redes de puntos se deben definir con base en normas ya establecidas y reguladas por la Organización de Aviación Civil Internacional (OACI. Entre las características más sobresalientes para la determinación de los puntos están el vínculo al Sistema Geodésico Mundial WGS84 y, evidentemente, la exactitud en las coordenadas de los puntos, la cual es fundamental para garantizar las actividades propias de la navegación aérea. Se expondrán a continuación los resultados obtenidos al aplicar la metodología GPS cinemática en la determinación de estos puntos.

  18. Comparação de três receptores GPS para uso em agricultura de precisão Comparison of three GPS receiver for precision agriculture uses

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    Marcelo C. C. Stabile

    2006-04-01

    Full Text Available Diversos equipamentos que se utilizam dos sinais transmitidos pelo Sistema de Posicionamento Global (GPS têm sido empregados na Agricultura de Precisão. Neste estudo, foi feita uma comparação de três receptores comerciais no intuito de verificar suas acurácias. As principais qualidades medidas foram a repetibilidade dos dados e a estabilidade do sistema. O estudo foi conduzido em campo aberto, na área experimental da ESALQ/USP, com três linhas paralelas de 50 m espaçadas 10 m entre si. A coleta de dados foi feita no dia 25-9-2002, totalizando seis repetições da comparação dos três sistemas. Os dados foram coletados simultaneamente, de acordo com a melhor configuração da constelação de satélites, sendo que os três sistemas apresentaram resultados distintos. O GPS "A" (oito canais, sem correção diferencial apresentou a maior variabilidade e a menor repetibilidade, com desvios de quase 10 m numa mesma linha. O sistema "B", com sinal de correção diferencial (DGPS "B", 12 canais, apresentou acurácia superior ao "A", com desvios de, no máximo, 6 m, mas com repetibilidade significativa. O GPS "C" (12 canais, com algoritmo otimizado apresentou a maior acurácia e desvio máximo de 2 m. Assim, os dois últimos sistemas são adequados para a aplicação dos conceitos da Agricultura de Precisão.Several brands of equipment have been used with global positioning systems (GPS in Precision Agriculture. The quality of these different receivers varies according to their capabilities in terms of accuracy and repeatability. In this study, three commercial systems were tested to compare their accuracies. This study focused on measuring the stability of the receiver and the repeatability of data. The study was conducted in the experimental area of ESALQ/USP. It consisted of three parallel 50-meter lines spaced 10 meters apart. Data collection was done on 9-25-2002 with a total of six replications. Data was collected simultaneously and the

  19. Estudio de las observaciones de tropopausa sobre el cono sur de Sudamérica mediante GPS a bordo de los satélites SAC-C y CHAMP Tropopause observation study over southern South America using GPS data from SAC-C and CHAMP satellites

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    S. Gabriela Lakkis

    2006-12-01

    Full Text Available En este trabajo se analiza la validez de la técnica de radio ocultación satelital (GPS llevada a cabo por los satélites SAC-C y CHAMP en tres estaciones chilenas y cuatro argentinas, como referencia del Cono Sur, durante el período 2001-2003. La validez de la técnica se discute por medio de la comparación de los parámetros atmosféricos obtenidos a partir de los satélites con los valores de radiosondeo. Una vez validada la ocultación para las latitudes estudiadas, en función de los datos satelitales se calcula temperatura, presión y altura de la tropopausa, así como valores de presión de vapor de agua y su comportamiento. De los resultados obtenidos del trabajo surge que las ocultaciones arrojan valores que se ajustan muy bien a los tradicionales radiosondeos, especialmente en la zona atmosférica comprendida entre superficie y los 10 kilómetros. De los registros satelitales se estimó que la tropopausa extratropical entre las longitudes 80° S y 60° S presenta valores de temperatura que fluctúan entre los 204 y los 222 K para el Hemisferio Sur hasta el trópico de Capricornio, con una altura mínima de 9 kilómetros y una máxima de 15.3 kilómetros. Para los valores de presión de vapor de agua se observó un comportamiento fuertemente decreciente a medida que se asciende desde la troposfera, hasta llegar a la estabilización en la estratosfera una vez atravesada la tropopausa, donde la variable presenta un cambio en la tasa de variación.Validation of radio occultation technique by Global Positioning System (GPS, carried out on board the SAC-C and CHAMP satellites, is analyzed over three stations of Chile and four for Argentine, as a reference for South America during 2001-2003. The discussion is based on the statistical comparison of the data of GPS with data from nearby radiosonde measurements. Though the occultation concept for obtaining profiles of atmospheric parameters, data derived from GPS, were used to calculate

  20. Hacking GPS

    CERN Document Server

    Kingsley-Hughes, Kathie

    2005-01-01

    * This is the "user manual" that didn't come with any of the 30 million GPS receivers currently in use, showing readers how to modify, tweak, and hack their GPS to take it to new levels!* Crazy-cool modifications include exploiting secret keycodes, revealing hidden features, building power cords and cables, hacking the battery and antenna, protecting a GPS from impact and falls, making a screen protector, and solar-powering a GPS* Potential power users will take the function and performance of their GPS to a whole new level by hacking into the firmware and hacking into a PC connection with a GPS* Fear not! Any potentially dangerous mod (to the device) is clearly labeled, with precautions listed that should be taken* Game time! Readers can check out GPS games, check into hacking geocaching, and even use a GPS as a metal detector

  1. Experiencia mexicana en el diseño de seguros ganaderos paramétricos satelitales de tipo catastrófico: bases conceptuales y teóricas

    Directory of Open Access Journals (Sweden)

    Fernando Paz

    2018-04-01

    Full Text Available El desarrollo de instrumentos de gestión de riesgos climáticos permite instrumentar acciones de adaptación ante el cambio climático, además de hacer eficiente el uso de recursos financieros para mitigar los impactos. En México, el empleo de estos instrumentos no se ha documentado, por lo que en este trabajo se desarrolla un marco conceptual-teórico para la instrumentación de seguros ganaderos paramétricos satelitales, con la finalidad de exponer sus ventajas y delimitar sus alcances. Para tal fin, se aplicaron los conceptos de unidad de riesgo, umbral de pago y elementos asociados al seguro, para establecer el riesgo climático que se asocia a las actividades agropecuarias, principalmente por sequías. Bajo el requerimiento crítico de una relación lineal entre el índice espectral y la biomasa vegetal, sin constante aditiva, se usó el índice espectral NDVIcp, optimizado por diversos efectos, lo que dio lugar al desarrollo de un esquema de seguro técnicamente sólido, sin el requisito de contar con información histórica de producción agropecuaria y que, además, refleja fielmente la realidad en campo. Todo lo anterior, permitió sentar las bases para el diseño de un seguro ganadero paramétrico satelital de tipo catastrófico sólido, transparente y conceptualmente accesible a los usuarios del mismo.

  2. GPS Composite Clock Analysis

    OpenAIRE

    Wright, James R.

    2008-01-01

    The GPS composite clock defines GPS time, the timescale used today in GPS operations. GPS time is illuminated by examination of its role in the complete estimation and control problem relative to UTC/TAI. The phase of each GPS clock is unobservable from GPS pseudorange measurements, and the mean phase of the GPS clock ensemble (GPS time) is unobservable. A new and useful observability definition is presented, together with new observability theorems, to demonstrate explicitly that GPS time is...

  3. Avaliação da acurácia de um gps de dupla frequência para implantação de um ponto de apoio imediato (P2 ao georreferenciamento.

    Directory of Open Access Journals (Sweden)

    Eduardo Leonel Bottega

    2011-05-01

    Full Text Available Este trabalho objetivou avaliar a acurácia de um receptor GPS de dupla frequência na aquisição de coordenadas para implantação de um ponto de apoio imediato (P2 ao georreferenciamento. Foi utilizado um receptor GPS de dupla freqüência (L1/L2, marca Ashtech, modelo Z-Xtreme. Para a determinação da acurácia, realizou-se o transporte de coordenadas geodésicas para o marco MS45 da rede GPS/MS através da triangulação com os pontos pertencentes à Rede Brasileira de Monitoramento Contínuo – RBMC: Estação de Uberlândia (UBER e Estação de Cuiabá (CUIB com coordenadas no datum SIRGAS2000. Foram realizadas coletas em quatro distintos tempos (5, 7, 9 e 11 horas e quatro repetições. Os dados coletados foram processados internamente no aparelho e pós-processados para correção diferencial utilizando software fornecido pelo fabricante. No pós-processamento, utilizou-se para os cálculos, arquivos no formato SP3. Foi considerada satisfatória e aceitável a exatidão obtida no tempo onde todas as repetições apresentaram erro inferior a 20 cm, assegurando assim a capacidade do aparelho em estabelecer pontos de apoio imediato (P2 realizando o transporte de coordenadas, pelo método da triangulação, entre pontos com distância acima de 700 km. Concluiu-se insuficiente a exatidão obtida pelo aparelho na obtenção de um ponto de apoio imediato ao georreferenciamento (P2 nas condições anteriormente citadas.

  4. De GPS al mapa

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

    Full Text Available Las coordenadas Lambert obtenidas a partir de mediciones con equipos GPS de mano, llamados a veces navegadores, en ciertos casos confunden al usuario, por diferir claramente de su posición real al ser graficadas en un mapa del Instituto Geográfico Nacional (IGN: Esto puede resolverse con suficiente exactitud mediante una transformación de Molodensky, seguida de la correspondiente proyección cartográfica. Sin embargo, los tres parámetros necesarios para la transformación, supuestamente válidos para Costa Rica, se encuentran en muchas variantes y producen obviamente resultados diferentes. En este trabajo se analizan los fundamentos del problema y sus posibles soluciones, culminando con un estudio comparativo de ocho casos, que permite seleccionar los valores más adecuados para los parámetros.

  5. Gestió mapes i GPS

    OpenAIRE

    Díaz Sañudo, Daniel

    2013-01-01

    El projecte denominat "Gestor de mapes i GPS" és una aplicació per a dispositius mòbils Android que utilitza l'API v.1 de Google Maps. El proyecto denominado "Gestor de mapas y GPS" es una aplicación para dispositivos móviles Android que utiliza la API v.1 de Google Maps.

  6. Diseño e implementación de una aplicación visual para el control de flotas basado en GPS

    OpenAIRE

    Cerrato Miranda, Javier

    2011-01-01

    Al igual que Helios, Dios griego del Sol, surcaba el cielo en su carro divisando a la humanidad y conociendo en todo momento donde se encontraba cada persona, actualmente los modernos sistemas de posicionamiento nos permiten conocer nuestra posición o localizar la ubicación de otros posibles dispositivos. HELIOS GPS TRACKING es una aplicación cliente-servidor que, haciendo uso del sistema GPS (Global Positioning System) y de la aplicación Google Maps, permite conocer la posición de un vehícul...

  7. GPS & Roadpricing

    DEFF Research Database (Denmark)

    Zabic, Martina

    2005-01-01

    den enkelte bil med en computer, der ved hjælp af signaler fra satellitter, kan bestemme bilens placering på vejnettet. Herved kan bilens computer ved hjælp af elektroniske vejkort udregne kilometertaksten det pågældende sted, således at det skyldige beløb enten trækkes direkte eller akkumuleres til...... estimeringskvaliteten af positionen, som specielt ses når bilerne accelererer, deaccelererer og drejer hurtigt i sving m.m. Hver GPS-baseret observations nøjagtighed afhænger af antallet af satellitter inden for ”sigt”, kvaliteten af hvert signal (HDOP) og den retning satellitterne befinder sig i forhold til enheden og...

  8. DESARROLLO DE UN PENETRÓMETRO INTEGRADO CON TECNOLOGÍA GPS-RTK PARA LA GENERACIÓN DE MAPAS DE RESISTENCIA A LA PENETRACIÓN DEL SUELO

    Directory of Open Access Journals (Sweden)

    Santos Gabriel Campos Magaña

    2015-04-01

    Full Text Available La agricultura de precisión requiere información precisa acerca de las propiedades del suelo para optimizar la aplicación de insumos y satisfacer necesidades específicas de los cultivos. En particular, la resistencia a la penetración (RP que es un factor que mide la compactación del suelo, la cual limita el crecimiento de las raíces y el rendimiento del cultivo, lo cual requiere ubicar y cuantificar el valor de RP. El presente trabajo describe el desarrollo de un penetrómetro integrado con dos sensores (resistencia y profundidad aplicados junto con tecnología de Posicionamiento Cinemátio en Tiempo Real-Sistema de Posicionamiento Global para Agricultura (RTK-AgGPS para la generación de mapas de diagnóstico de capas compactadas. El primer sensor fue desarrollado para la medición de la RP utilizando un transductor de anillo simple con capacidad de hasta 9 MPa, con una sensibilidad de 13.5 Nm V-1 y un coeficiente de correlación de 99.6% entre la fuerza aplicada y el voltaje de salida. El segundo sensor, se adecuó para determinar la profundidad de RP con un desplazamiento de trabajo máximo de 0.60 m, con una sensibilidad de 258.5 mm V-1 y un coeficiente de correlación de 100% entre la profundidad de penetración y voltaje de salida. Para la evaluación en campo, se construyó un carro porta-sensores acoplado al enganche del tractor para el accionamiento del actuador hidráulico del penetrómetro. Se realizó un muestreo sistemático de 30 puntos utilizando la tecnología RTK-GPS obteniendo los valores y localización geo referenciada de RP con una precisión de 0.025 m en una profundidad de trabajo hasta de 0.40 m, esto permitió la generación de mapas de diagnóstico de la RP empleando un Sistema de Información Geográfica para tres profundidades diferentes de 0.20, 0.30 y 0.40 m.

  9. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  10. GPS de precisión por el método estático relativo para puntos en aeropuertos

    Directory of Open Access Journals (Sweden)

    Julio Roldán Rodríguez

    2016-03-01

    Full Text Available Todo país o región tiene su marco de referencia geodésico definido por un conjunto de parámetros específicos de referencia establecido por mediciones convencionales. Las discrepancias en orientación, traslación y escala respecto a un sistema único mundial, actualmente el Marco Internacional de Referencia Terrestre 2000, abreviado con las siglas en ingles ITRF00, traen consecuencias en la navegación aérea cuando se utiliza el GPS, debido a que las discrepancias citadas generan errores planimétricos desde decenas de metros hasta centenas de metros. Ante esta situación se da la necesidad de establecer en el ámbito mundial criterios de estandarización en la georreferenciación, adoptándose como sistema común de referencia geodésica en la Aviación Civil Internacional, el WGS84 con el ITRF00. En la actualidad, la estandarización en la georreferenciación se da no sólo en la aviación civil sino también en todos los campos de la geodesia, cartografía y catastro.

  11. GPS Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Global Positioning System (GPS) Test Facility Instrumentation Suite (GPSIS) provides great flexibility in testing receivers by providing operational control of...

  12. GPS system simulation methodology

    Science.gov (United States)

    Ewing, Thomas F.

    1993-01-01

    The following topics are presented: background; Global Positioning System (GPS) methodology overview; the graphical user interface (GUI); current models; application to space nuclear power/propulsion; and interfacing requirements. The discussion is presented in vugraph form.

  13. The Statistics of GPS

    National Research Council Canada - National Science Library

    Matsakis, Demetrios

    2007-01-01

    The Global Positioning System (GPS) is an extremely effective satellite-based system that broadcasts sufficient information for a user to determine time and position from any location on or near the Earth...

  14. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

  15. GPS Ephemeris Message Broadcast Simulation

    National Research Council Canada - National Science Library

    Browne, Nathan J; Light, James J

    2005-01-01

    The warfighter constantly needs increased accuracy from GPS and a means to increasing this accuracy to the decimeter level is a broadcast ephemeris message containing GPS satellite orbit and clock corrections...

  16. Variability in GPS sources

    NARCIS (Netherlands)

    Jauncey, DL; King, EA; Bignall, HE; Lovell, JEJ; Kedziora-Chudczer, L; Tzioumis, AK; Tingay, SJ; Macquart, JP; McCulloch, PM

    2003-01-01

    Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, similar to10%, vary. Their variability falls

  17. Semantic Enrichment of GPS Trajectories

    NARCIS (Netherlands)

    de Graaff, V.; van Keulen, Maurice; de By, R.A.

    2012-01-01

    Semantic annotation of GPS trajectories helps us to recognize the interests of the creator of the GPS trajectories. Automating this trajectory annotation circumvents the requirement of additional user input. To annotate the GPS traces automatically, two types of automated input are required: 1) a

  18. Efficient GPS Position Determination Algorithms

    National Research Council Canada - National Science Library

    Nguyen, Thao Q

    2007-01-01

    ... differential GPS algorithm for a network of users. The stand-alone user GPS algorithm is a direct, closed-form, and efficient new position determination algorithm that exploits the closed-form solution of the GPS trilateration equations and works...

  19. Indoor Positioning Using GPS Revisited

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Blunck, Henrik; Godsk, Torben

    2010-01-01

    It has been considered a fact that GPS performs too poorly inside buildings to provide usable indoor positioning. We analyze results of a measurement campaign to improve on the understanding of indoor GPS reception characteristics. The results show that using state-of-the-art receivers GPS...... low signal-to-noise ratios, multipath phenomena or bad satellite constellation geometry. We have also measured the indoor performance of embedded GPS receivers in mobile phones which provided lower availability and accuracy than state-of-the-art ones. Finally, we consider how the GPS performance...

  20. GPS antenna designs

    Science.gov (United States)

    Laube, Samuel J. P.

    1987-05-01

    Application of the current GPS NAVSTAR system to civilian service requires that a right hand, circularly polarized, -160 dBW spread spectrum signal be received from an orbiting satellite, where the antenna environment is also moving. This presents a design challenge when inexpensive antennas are desired. The intent of this survey is to provide information on the antennas mentioned and to construct and test prototypes to determine whether the choice made by the industry, the quadrifilar helix, is the best. The helix antenna is currently the low cost standard for GPS. Prototype versions were constructed using 12 gauge wire and subminiature coaxial hardline. The constructed antennas were tested using a signal generator and a reference turnstile. A spectrum analyzer was used to measure the level of the received signal.

  1. GPS & Galileo. Friendly Foes?

    Science.gov (United States)

    2007-04-01

    some of their data, others employ different techniques. United States defense contractor Lockheed Martin developed an anti-jam GPS receiver in 2000 for...Europe in a New Generation of Satellite Navigation Services,” European Commission (9 Feb 1999): 16. 25. Ibid. 26. Anne Jolis , “Problems Run Rampant...European Outer Space,” Euro Topics (19 March 2007), found at http://www.eurotopics.net/en/presseschau/archiv/archiv_dossier/DOSSIER15435. 40. Jolis

  2. Standardization of GPS data processing

    International Nuclear Information System (INIS)

    Park, Pil Ho

    2001-06-01

    A nationwide GPS network has been constructed with about 60 permanent GPS stations after late 1990s in Korea. For using the GPS in variety of application area like crustal deformation, positioning, or monitoring upper atmosphere, it is necessary to have ability to process the data precisely. Now Korea Astronomy Observatory has the precise GPS data processing technique in Korea because it is difficult to understand characteristics of the parameters we want to estimate, resolve the integer ambiguity, and analyze many errors. There are three reliable GPS data processing software in the world ; Bernese(University of Berne), GIPSY-OASIS(JPL), GAMIT(MIT). These software allow us to achieve millimeter accuracy in the horizontal position and about 1 cm accuracy vertically even for regional networks with a diameter of several thousand kilometers. But we established the standard of GPS data processing using Bernese as main tool and GIPSY O ASIS as side

  3. Sensing Human Activity: GPS Tracking

    Science.gov (United States)

    van der Spek, Stefan; van Schaick, Jeroen; de Bois, Peter; de Haan, Remco

    2009-01-01

    The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres, Norwich, Rouen and Koblenz, and in another experiment for collecting activity data of 13 families in Almere (The Netherlands) for one week. The question posed in this paper is: what is the value of GPS as ‘sensor technology’ measuring activities of people? The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research. PMID:22574061

  4. Sensing Human Activity: GPS Tracking

    Directory of Open Access Journals (Sweden)

    Remco de Haan

    2009-04-01

    Full Text Available The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres, Norwich, Rouen and Koblenz, and in another experiment for collecting activity data of 13 families in Almere (The Netherlands for one week. The question posed in this paper is: what is the value of GPS as ‘sensor technology’ measuring activities of people? The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research.

  5. GPS: Public Utility or Software Platform

    Science.gov (United States)

    2016-09-01

    train for GPS loss, encourage use of GPS signal integrity monitors , develop in- vehicle GPS backups, and evaluate the range of radio...literature prevent the full quantification of exactly how vulnerable GPS is to service interruption. This thesis used constant comparison analysis to...criticality, resilience, and vulnerability. This methodology overcomes research limitations by using GPS system design, operations, and policies as

  6. The GPS odograph user's guide

    Science.gov (United States)

    The GPS-based Odograph Prototype (GOP or GPS Odograph) was developed in an effort sponsored by The Federal Highway Administration (FHWA). The purpose of this effort was to develop a means of using inexpensive commercial off-the-self laptop (or notebo...

  7. High Gain Advanced GPS Receiver

    National Research Council Canada - National Science Library

    Brown, Alison; Zhang, Gengsheng

    2006-01-01

    NAVSYS High Gain Advanced GPS Receiver (HAGR) uses a digital beam-steering antenna array to enable up to eight GPS satellites to be tracked, each with up to 10 dBi of additional antenna gain over a conventional receiver solution...

  8. Sensing human activity : GPS tracking

    NARCIS (Netherlands)

    van der Spek, Stefan; van Schaick, Jeroen; de Bois, P.G.; de Haan, Remco

    2009-01-01

    The enhancement of GPS technology enables the use of GPS devices not only as navigation and orientation tools, but also as instruments used to capture travelled routes: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for

  9. GPS Position Time Series @ JPL

    Science.gov (United States)

    Owen, Susan; Moore, Angelyn; Kedar, Sharon; Liu, Zhen; Webb, Frank; Heflin, Mike; Desai, Shailen

    2013-01-01

    Different flavors of GPS time series analysis at JPL - Use same GPS Precise Point Positioning Analysis raw time series - Variations in time series analysis/post-processing driven by different users. center dot JPL Global Time Series/Velocities - researchers studying reference frame, combining with VLBI/SLR/DORIS center dot JPL/SOPAC Combined Time Series/Velocities - crustal deformation for tectonic, volcanic, ground water studies center dot ARIA Time Series/Coseismic Data Products - Hazard monitoring and response focused center dot ARIA data system designed to integrate GPS and InSAR - GPS tropospheric delay used for correcting InSAR - Caltech's GIANT time series analysis uses GPS to correct orbital errors in InSAR - Zhen Liu's talking tomorrow on InSAR Time Series analysis

  10. Evidential recovery from GPS devices

    Directory of Open Access Journals (Sweden)

    Brian Cusack

    Full Text Available Global Positioning Systems (GPS have become more affordable, are now widely used in motor vehicles and in other frequently used applications. As a consequence GPS are increasingly becoming an important source of evidential data for digital forensic investigations. This paper acknowledges there are only disparate documents for the guidance of an investigator when extracting evidence form such systems. The focus of this paper is to provide the technical details of recovering artifacts from four GPS currently available to the New Zealand market. Navman brand GPS are used, following a forensically robust process. The steps of the process are described, results analysed and the associated risks are discussed. In addition, the paper discusses techniques related to the visual presentation of evidence suitable for Google Maps. Automation attempts to speed up the analysis to visualization steps are also included. The outcome is a road map that may assist digital forensic investigators develop GPS examination strategies for implementation in their own organizations.

  11. Precise GPS orbits for geodesy

    Science.gov (United States)

    Colombo, Oscar L.

    1994-01-01

    The Global Positioning System (GPS) has become, in recent years, the main space-based system for surveying and navigation in many military, commercial, cadastral, mapping, and scientific applications. Better receivers, interferometric techniques (DGPS), and advances in post-processing methods have made possible to position fixed or moving receivers with sub-decimeter accuracies in a global reference frame. Improved methods for obtaining the orbits of the GPS satellites have played a major role in these achievements; this paper gives a personal view of the main developments in GPS orbit determination.

  12. Hastighedskort for Danmark vha. GPS

    DEFF Research Database (Denmark)

    Andersen, Ove; Lahrmann, Harry; Torp, Kristian

    2011-01-01

    Hastighed på vejnettet er en central metrik indenfor trafikplanlægning og trafikoptimering. I denne artikel beskrives, hvorledes et hastighedskort for hele Danmark er skabt udelukkende vha. GPS data. To tilgangsvinkler til at beregne hastigheder vha. GPS data er præsenteret. Dette er hhv. en....... Opsummeret anses den turbaseret for at beregne det mest akkurate estimat, men metoden er meget datakrævende. Det er derfor nødvendigt at have den punktbaserede at falde tilbage på. Generelt mangler metoder til beregning af hastigheder vha. GPS data at blive valideret. Hvordan en sådan validering kan...

  13. 75 FR 8928 - Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800 Interface Control Working Group (ICWG...

    Science.gov (United States)

    2010-02-26

    ... DEPARTMENT OF DEFENSE Department of the Air Force Announcement of IS-GPS-200, IS-GPS-705, IS-GPS... document/s IS-GPS-200E (NAVSTAR GPS Space Segment/Navigation User Interfaces), IS-GPS-705A (NAVSTAR GPS Space Segment/User Segment L5 Interfaces), and IS-GPS-800A (NAVSTAR GPS Space Segment/User Segment L1C...

  14. LADOTD GPS technology management plan.

    Science.gov (United States)

    2012-02-01

    Over many years, Global Positioning System (GPS) technology has been adopted by different sections within the Louisiana : Department of Transportation and Development (DOTD), with no uniform standards for accuracy, operation, hardware, or : software....

  15. Scintillation-Hardened GPS Receiver

    Science.gov (United States)

    Stephens, Donald R.

    2015-01-01

    CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

  16. GPS Navigation and Tracking Device

    Directory of Open Access Journals (Sweden)

    Yahya Salameh Khraisat

    2011-10-01

    Full Text Available Since the introduction of GPS Navigation systems in the marketplace, consumers and businesses have been coming up with innovative ways to use the technology in their everyday life. GPS Navigation and Tracking systems keep us from getting lost when we are in strange locations, they monitor children when they are away from home, keep track of business vehicles and can even let us know where a philandering partner is at all times. Because of this we attend to build a GPS tracking device to solve the mentioned problems. Our work consists of the GPS module that collects data from satellites and calculates the position information before transmitting them to the user’s PC (of Navigation system or observers (of Tracking System using wireless technology (GSM.

  17. Characterization of meteorological parameters, solar radiation and effect of clouds at two antarctic sites, and comparison with satellite estimates Caracterización de parámetros meteorológicos, radiación solar y efecto de las nubes en dos sitios antárticos, y comparación con estimaciones satelitales

    Directory of Open Access Journals (Sweden)

    Eduardo A. Luccini

    2005-12-01

    ámetros entran como variables en cálculos de la irradiación solar diaria equivalente a cielo despejado, para determinar la transmitancia efectiva de radiación solar por nubes. El efecto de nubes fue mayor en Brown, con transmitancia efectiva media de 49%, respecto del 71% en BelgranoII. La irradiación media de 27.4MJ/m² en diciembre en BelgranoII es de las más altas registradas en el mundo. Asimismo, algunos días muestran incrementos de irradiación por sobre un 20% de la esperada para cielo despejado. La irradiación solar media en Antártida es considerablemente mayor que la registrada en el Ártico. Se comparan las mediciones con datos satelitales del Surface Meteorology and Solar Energy Data Set/NASA.

  18. GPS measurements in Satakunta area

    International Nuclear Information System (INIS)

    Poutanen, M.; Nyberg, S.; Ahola, J.

    2010-10-01

    The Finnish Geodetic Institute, the Geological Survey of Finland, Posiva Ltd and municipalities in the district of Satakunta launched the GeoSatakunta research program in 2002 to carry out interdisciplinary studies on regional bedrock stress field and to apply the results e.g. in land use planning in the Satakunta area. The area was chosen for many reasons. Its geological diversity, extensive multi-disciplinary data coverage, and various interests of participants made the area suitable for the project. The purpose of the GPS observations is to get detailed information on recent crustal deformations in the area. The Finnish Geodetic Institute maintains e.g. national GPS network, FinnRef, and since 1995 a local research network in the Olkiluoto area. The Satakunta network differs from these, and this is the first time to obtain such detailed information of a regional network in Finland. The Satakunta GPS network consists of 13 concrete pillars for episodic GPS campaigns and the Olkiluoto permanent GPS station in the FinnRef network. The distances between the concrete pillars are 10-15 km, and the sites were chosen in a co-operation with the Geological Survey of Finland taking into account the geological structures in the area. The City of Pori made the final reconnaissance in the field and constructed eight pillars in 2003. The original network was expanded in 2005-2006 in Eurajoki and Rauma, and at the City of Rauma joined the co-operation. The five new pillars join the previous Olkiluoto network into the Satakunta network. There have been three annual GPS campaigns in 2003-2008. Time series of the Satakunta network are shorter than in the Olkiluoto network, and also the distances are longer. Therefore, the same accuracy than in Olkiluoto has not yet achieved. However, mm-sized movements can be excluded. Estimated velocities were small (0.2 mm/a) and mostly statistically insignificant because of relatively short time series. In this publication we describe the

  19. Apoyo a Estudios Geodinamicos con GPS en Guatemala

    Science.gov (United States)

    Robles, V. R.

    2013-05-01

    El Instituto Geografico Nacional de Guatemala implemento 17 estaciones GNSS en el año 2009, como un proyecto de credito mixto de donacion de equipamiento del Gobierno de Suiza, el cual, este equipamiento de estaciones CORS GNSS es un sistema de recepción y transmisión de datos crudos GPS RInex que utiliza la tecnologia Spider Web de Leica, asi mismo este sistema esta sirviendo para el espablecimiento de un marco geodesico nacional de coordenadas geodesicas oficiales, el cual se calculan u obtienen las velocidades en tiempos temporales programados de las 17 Estaciones CORS. La infraestructura del marco geodesico de Guatemala esta sirviendo de base para las aplicaciones de estudios geodinamicos como el monitoreo de del desplazamiento de las placas tectonicas por medio de un estudio que se inicio en el año de 1999, llamado medicion con GPS el sistema de Fallas de los rios Polochic Motagua de Guatemala, tambien para un estudio que se implemento para deformación de corteza terrestre local en un Volcan Activo de Guatemala llamado Pacaya. Para el estudio de medicion con GPS en el sistema de falla de los Rios del polochic Motagua se implementaron 16 puntos para medir con GPS de dos frecuencias en el año de 1999, el cual, tres puntos son estaciones geodesicas CORS IGS llamados GUAT, ELEN y HUEH, despues en el año de 2003 se hizo otra medicion en un total de 20 puntos, que permitió calcular las velocidades de desplazamieinto de los puntos en mención, usando como referencia el modelo NUVEL 1A de DeMets de la placa de Norteamerica. Este estudio fue en cooperación internacional por la universidad de Nice de Francia y el IGNde Francia. Para el estudio del monitoreo con GPS del volcan activo de Guatemala, se implementaron cuatro puntos al rededor del volcan, el cual, se realizan cuatro mediciones al año, que permiten determinar axialmente la distancias entre los puntos, y rebisar estadisticamente cual es el comportamiento de las distancias en funcion del tiempo, si

  20. GPS/INS Sensor Fusion Using GPS Wind up Model

    Science.gov (United States)

    Williamson, Walton R. (Inventor)

    2013-01-01

    A method of stabilizing an inertial navigation system (INS), includes the steps of: receiving data from an inertial navigation system; and receiving a finite number of carrier phase observables using at least one GPS receiver from a plurality of GPS satellites; calculating a phase wind up correction; correcting at least one of the finite number of carrier phase observables using the phase wind up correction; and calculating a corrected IMU attitude or velocity or position using the corrected at least one of the finite number of carrier phase observables; and performing a step selected from the steps consisting of recording, reporting, or providing the corrected IMU attitude or velocity or position to another process that uses the corrected IMU attitude or velocity or position. A GPS stabilized inertial navigation system apparatus is also described.

  1. Inversion of GPS meteorology data

    Directory of Open Access Journals (Sweden)

    K. Hocke

    Full Text Available The GPS meteorology (GPS/MET experiment, led by the Universities Corporation for Atmospheric Research (UCAR, consists of a GPS receiver aboard a low earth orbit (LEO satellite which was launched on 3 April 1995. During a radio occultation the LEO satellite rises or sets relative to one of the 24 GPS satellites at the Earth's horizon. Thereby the atmospheric layers are successively sounded by radio waves which propagate from the GPS satellite to the LEO satellite. From the observed phase path increases, which are due to refraction of the radio waves by the ionosphere and the neutral atmosphere, the atmospheric parameter refractivity, density, pressure and temperature are calculated with high accuracy and resolution (0.5–1.5 km. In the present study, practical aspects of the GPS/MET data analysis are discussed. The retrieval is based on the Abelian integral inversion of the atmospheric bending angle profile into the refractivity index profile. The problem of the upper boundary condition of the Abelian integral is described by examples. The statistical optimization approach which is applied to the data above 40 km and the use of topside bending angle profiles from model atmospheres stabilize the inversion. The retrieved temperature profiles are compared with corresponding profiles which have already been calculated by scientists of UCAR and Jet Propulsion Laboratory (JPL, using Abelian integral inversion too. The comparison shows that in some cases large differences occur (5 K and more. This is probably due to different treatment of the upper boundary condition, data runaways and noise. Several temperature profiles with wavelike structures at tropospheric and stratospheric heights are shown. While the periodic structures at upper stratospheric heights could be caused by residual errors of the ionospheric correction method, the periodic temperature fluctuations at heights below 30 km are most likely caused by atmospheric waves (vertically

  2. ESTUDIO DE LA VARIABILIDAD ESPACIAL DE LA TEMPERATURA DE SUPERFICIE EN EL NORTE DE LA PROVINCIA DEL NEUQUÉN CON IMÁGENES SATELITALES

    Directory of Open Access Journals (Sweden)

    Marisa Gloria Cogliati

    2015-12-01

    Full Text Available La zona noroeste de la provincia del Neuquén constituye una zona importante debido a su utilización con fines ganaderos, pero los sistemas áridos o semi áridos como el estudiado en el presente trabajo son vulnerables a procesos de uso del suelo y desertización. En este trabajo se presenta el análisis de la temperatura de superficie obtenida a partir de información del canal térmico del satélite Landsat 7 ETM+ para esa región durante un periodo fresco (otoño-invierno y cálido (primavera-verano. El estudio es parte de un proyecto de análisis geoecológico utilizando imágenes Landsat. La zona no cuenta con estudios de la variabilidad espacial de la temperatura del aire y del suelo debido a la necesidad de contar con redes de información micro o meso meteorológicas que incorporen una mayor densidad espacial de observaciones siguiendo el gradiente altitudinal y la complejidad del terreno debido a que el área es de difícil acceso y ho hay datos de superficie disponibles. Esto hace necesario utilizar métodos alternativos para el estudio de la distribución espacial de variables topo meteorológicas. La información satelital provee información en distintas escalas temporales y espaciales a un menor costo. En el presente trabajo, se obtuvo la radiancia emitida en la superficie utilizando la radiancia medida por el satélite a partir de la ecuación de transferencia radiativa y el modelo MODTRAN con información de reanálisis disponibles en línea. Se analizaron seis escenas libres de nubosidad. La temperatura de superficie presentó un comportamiento correlacionado con la topografía principalmente en el período frío, con una menor relación en verano. La isoterma de 273 K (0 oC alcanzó alturas de 1900 m, restringiéndose a alturas mayores a 3700 m en verano. Las áreas con temperatura menor a 273 K fueron las que presentaron mayores diferencias entre el período cálido y el período frío analizados

  3. GPS test range mission planning

    Science.gov (United States)

    Roberts, Iris P.; Hancock, Thomas P.

    The principal features of the Test Range User Mission Planner (TRUMP), a PC-resident tool designed to aid in deploying and utilizing GPS-based test range assets, are reviewed. TRUMP features time history plots of time-space-position information (TSPI); performance based on a dynamic GPS/inertial system simulation; time history plots of TSPI data link connectivity; digital terrain elevation data maps with user-defined cultural features; and two-dimensional coverage plots of ground-based test range assets. Some functions to be added during the next development phase are discussed.

  4. Implementing GPS into Pave-IR.

    Science.gov (United States)

    2009-03-01

    To further enhance the capabilities of the Pave-IR thermal segregation detection system developed at the Texas Transportation Institute, researchers incorporated global positioning system (GPS) data collection into the thermal profiles. This GPS capa...

  5. GPS operations at Olkiluoto in 2011

    Energy Technology Data Exchange (ETDEWEB)

    Koivula, H.; Kallio, U.; Nyberg, S.; Jokela, J.; Poutanen, M. [Finnish Geodetic Institute, Masala (Finland)

    2012-06-15

    The Finnish Geodetic Institute has studied crustal deformations at Olkiluoto, Kivetty and Romuvaara in co-operation with Posiva Oy since 1995. At Olkiluoto a total of 32 GPS campaigns have been carried out at inner network since 1995 and 17 campaigns at outer network since 2003. Kivetty and Romuvaara were not measured in 2011. In the Olkiluoto inner network 80 percent of the estimated change rates are smaller than 0.10 mm/a. One third of the change rates are statistically significant. They are mainly related to the Olkiluoto permanent station (GPS1) and to the pillars GPS6 and GPS13. The change rates related to GPS6 are not realistic due to the site-specific changes affecting the time series. The maximum change rate (-0.20 mm/a {+-} 0.05 mm/a) is related to GPS13. The time series of GPS13 is half the length of other pillars and therefore, the change rates are more uncertain. In the Olkiluoto outer network the maximum and statistically significant change rate is between GPS1-GPS11 (0.39 mm/a {+-} 0.06 mm/a). Pillar GPS12 was not observed this year. The change rates of baselines GPS1-GPS14 and GPS1-GPS15 are first time statistically significant. The change rates indicate a small movement of the GPS1 pillar. The baseline GPS1-GPS11 crosses an old fracture zone locating in the direction of the Eurajoensalmi, which might be a reason for the deformation. On the other hand, the Onkalo excavations in the vicinity of the Olkiluoto permanent station (GPS1) may cause some movement. Electronic distance measurements have been performed at Olkiluoto at the baseline GPS7-GPS8 using the Mekometer since 2002. The measurements have been carried out simultaneously with GPS campaigns. Based on 19 measurements in 10 years, the trends of the two time series seems to be similar. Due to unmodelled or dismodelled geometrical offsets and the scale difference between GPS measurements and EDM there is about 0.3 mm difference between distances GPS7-GPS8 derived from GPS measurements and EDM

  6. GPS operations at Olkiluoto in 2011

    International Nuclear Information System (INIS)

    Koivula, H.; Kallio, U.; Nyberg, S.; Jokela, J.; Poutanen, M.

    2012-06-01

    The Finnish Geodetic Institute has studied crustal deformations at Olkiluoto, Kivetty and Romuvaara in co-operation with Posiva Oy since 1995. At Olkiluoto a total of 32 GPS campaigns have been carried out at inner network since 1995 and 17 campaigns at outer network since 2003. Kivetty and Romuvaara were not measured in 2011. In the Olkiluoto inner network 80 percent of the estimated change rates are smaller than 0.10 mm/a. One third of the change rates are statistically significant. They are mainly related to the Olkiluoto permanent station (GPS1) and to the pillars GPS6 and GPS13. The change rates related to GPS6 are not realistic due to the site-specific changes affecting the time series. The maximum change rate (-0.20 mm/a ± 0.05 mm/a) is related to GPS13. The time series of GPS13 is half the length of other pillars and therefore, the change rates are more uncertain. In the Olkiluoto outer network the maximum and statistically significant change rate is between GPS1-GPS11 (0.39 mm/a ± 0.06 mm/a). Pillar GPS12 was not observed this year. The change rates of baselines GPS1-GPS14 and GPS1-GPS15 are first time statistically significant. The change rates indicate a small movement of the GPS1 pillar. The baseline GPS1-GPS11 crosses an old fracture zone locating in the direction of the Eurajoensalmi, which might be a reason for the deformation. On the other hand, the Onkalo excavations in the vicinity of the Olkiluoto permanent station (GPS1) may cause some movement. Electronic distance measurements have been performed at Olkiluoto at the baseline GPS7-GPS8 using the Mekometer since 2002. The measurements have been carried out simultaneously with GPS campaigns. Based on 19 measurements in 10 years, the trends of the two time series seems to be similar. Due to unmodelled or dismodelled geometrical offsets and the scale difference between GPS measurements and EDM there is about 0.3 mm difference between distances GPS7-GPS8 derived from GPS measurements and EDM. It is

  7. Location - Global Positioning System (GPS) Photos

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — Digital photos tagged with GPS location information. The St. Paul District maintains a digital library of over 10,000 GPS photos. Photos are often associated with...

  8. Contents of GPS Data Files

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, John P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carver, Matthew Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Norman, Benjamin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-09

    There are no very detailed descriptions of most of these instruments in the literature – we will attempt to fix that problem in the future. The BDD instruments are described in [1]. One of the dosimeter instruments on CXD boxes is described in [2]. These documents (or web links to them) and a few others are in this directory tree. The cross calibration of the CXD electron data with RBSP is described in [3]. Each row in the data file contains the data from one time bin from a CXD or BDD instrument along with a variety of parameters derived from the data. Time steps are commandable but 4 minutes is a typical setting. These instruments are on many (but not all) GPS satellites which are currently in operation. The data come from either BDD instruments on GPS Block IIR satellites (SVN41 and 48), or else CXD-IIR instruments on GPS Block IIR and IIR-M satellites (SVN53-61) or CXD-IIF instruments on GPS block IIF satellites (SVN62-73). The CXD-IIR instruments on block IIR and IIR(M) satellites use the same design.

  9. Continuous professional development for GPs

    DEFF Research Database (Denmark)

    Kjaer, N K; Steenstrup, A P; Pedersen, L B

    2014-01-01

    out to identify GPs' current use of CPD and to explore the motives behind their choices. METHODS: A mixed-methods study with a combined qualitative and quantitative approach was used. In 2012, two focus group interviews were conducted, followed up the same year by an online questionnaire sent to 1079...

  10. Tracking Small Satellites using Translated GPS

    OpenAIRE

    Lefevre, Don; Mulally, Daniel

    1991-01-01

    This paper discusses using translated GPS for tracking small satellites, the technical trade-offs involved, and the position and timing accuracies which are achievable using translated GPS. The Global Positioning System (GPS) uses the relative times-of-arrival of multiple spread-spectrum signals at an antenna to determine the position of the antenna. The system can also determine the time the antenna was at that position. The direct sequence spread spectrum signals are transmitted from GPS sa...

  11. The SMS-GPS-Trip-Method

    DEFF Research Database (Denmark)

    Reinau, Kristian Hegner; Harder, Henrik; Weber, Michael

    2015-01-01

    This article presents a new method for collecting travel behavior data, based on a combination of GPS tracking and SMS technology, coined the SMS–GPS-Trip method. The state-of-the-art method for collecting data for activity based traffic models is a combination of travel diaries and GPS tracking...

  12. Integrated navigation of aerial robot for GPS and GPS-denied environment

    International Nuclear Information System (INIS)

    Suzuki, Satoshi; Min, Hongkyu; Nonami, Kenzo; Wada, Tetsuya

    2016-01-01

    In this study, novel robust navigation system for aerial robot in GPS and GPS- denied environments is proposed. Generally, the aerial robot uses position and velocity information from Global Positioning System (GPS) for guidance and control. However, GPS could not be used in several environments, for example, GPS has huge error near buildings and trees, indoor, and so on. In such GPS-denied environment, Laser Detection and Ranging (LIDER) sensor based navigation system have generally been used. However, LIDER sensor also has an weakness, and it could not be used in the open outdoor environment where GPS could be used. Therefore, it is desired to develop the integrated navigation system which is seamlessly applied to GPS and GPS-denied environments. In this paper, the integrated navigation system for aerial robot using GPS and LIDER is developed. The navigation system is designed based on Extended Kalman Filter, and the effectiveness of the developed system is verified by numerical simulation and experiment. (paper)

  13. Ionospheric Scintillation Effects on GPS

    Science.gov (United States)

    Steenburgh, R. A.; Smithtro, C.; Groves, K.

    2007-12-01

    . Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

  14. GPS-Aided Video Tracking

    Directory of Open Access Journals (Sweden)

    Udo Feuerhake

    2015-08-01

    Full Text Available Tracking moving objects is both challenging and important for a large variety of applications. Different technologies based on the global positioning system (GPS and video or radio data are used to obtain the trajectories of the observed objects. However, in some use cases, they fail to provide sufficiently accurate, complete and correct data at the same time. In this work we present an approach for fusing GPS- and video-based tracking in order to exploit their individual advantages. In this way we aim to combine the reliability of GPS tracking with the high geometric accuracy of camera detection. For the fusion of the movement data provided by the different devices we use a hidden Markov model (HMM formulation and the Viterbi algorithm to extract the most probable trajectories. In three experiments, we show that our approach is able to deal with challenging situations like occlusions or objects which are temporarily outside the monitored area. The results show the desired increase in terms of accuracy, completeness and correctness.

  15. Parametrización y optimización de modelos de inversión para la obtención de humedad del suelo a partir de datos satelitales de Radares de Apertura Sintética

    OpenAIRE

    Barber, Matías Ernesto

    2013-01-01

    Dentro del Plan Espacial Nacional (PEN), la Comisión Nacional de Actividades Espaciales (CONAE) tiene previsto el lanzamiento de la misión satelital SAOCOM, un radar de apertura sintética (SAR) que opera en microondas (λ = 23cm) y cuyo principal objetivo es la estimación de humedad del suelo sobre Pampa Húmeda. El problema de la estimación de variables biogeofísicas a partir de imágenes SAR es un problema mal condicionado, donde con frecuencia existen muchas combinaciones de parámetros de la ...

  16. Implementación de un método operativo para la estimación de la temperatura superficial terrestre en la Región Callao usando datos de las imágenes satelitales

    OpenAIRE

    Mendoza Nolorbe, Juan Neil

    2014-01-01

    El sensor TM del satélite Landsat 5 ha registrado datos imágenes de la superficie de la Tierra desde el año 1984 hasta inicios del año 2013, con una resolución espacial de 30m y con una frecuencia de visita cada 16 días. Los datos imágenes de este sensor son del tipo multiespectral, registrados por seis bandas espectrales, en el rango del espectro visible, infrarrojo cercano e infrarrojo térmico. La banda térmica (banda 6) del sensor TM ofrece la oportunidad de determinar la temperatura de la...

  17. GPS deformation measurements at Olkiluoto in 2013

    International Nuclear Information System (INIS)

    Nyberg, S.; Kallio, U.; Koivula, H.

    2014-08-01

    The Finnish Geodetic Institute has monitored crustal deformations since mid-1990s at Olkiluoto, Kivetty and Romuvaara. The research was focused on the Olkiluoto area in 2001, when Olkiluoto was chosen to the site for the final disposal facility of the spent nuclear fuel. The work and the results of the GPS deformation monitoring at Olkiluoto in 2013 are presented. The measurement consisted of two GPS measurement campaigns, observations at local permanent stations and control markers measurements at four stations. In spring six new stations were set up for permanent tracking. In total 12 permanent stations were operating continuously from April to the end of the year. The residual time series of the stations showed periodic trends up to 3 mm in height and 1 mm in horizontal component relative to the GPS1 station. A few stations were still measured as campaign-based and analysed baseline by baseline. The data from permanent stations (GPS1-GPS9, and GPS13) were included. The analysis of the inner network based on campaign sessions showed very small motions as in previous years: 75 % of change rates are smaller than 0.10 mm/y. Roughly one third of the change rates could be considered statistically significant at 1 % significance level. Statistically significant change rates were estimated for baselines from GPS1 and GPS5. The trends and strains differed at some baselines clearly from the earlier analysis because of different troposphere modelling. The results of the outer network showed the largest difference on the baseline GPS1-GPS11 where the trend decreased from -0.42 mm/y to -0.28 mm/y. The strain pattern of the outer network shows an eastwards motion of GPS1. The estimated strains for the baselines east of GPS1 were -0.03/-0.04 ppm/y. The control marker measurements were carried at the stations GPS1, GPS2, GPS4 and GPS6. A comparison of the results with the previous measurements showed that the distance between control markers at GPS6 continues to increase. Also

  18. GPS deformation measurements at Olkiluoto in 2013

    Energy Technology Data Exchange (ETDEWEB)

    Nyberg, S.; Kallio, U.; Koivula, H. [Finnish Geodetic Institute, Masala (Finland)

    2014-08-15

    The Finnish Geodetic Institute has monitored crustal deformations since mid-1990s at Olkiluoto, Kivetty and Romuvaara. The research was focused on the Olkiluoto area in 2001, when Olkiluoto was chosen to the site for the final disposal facility of the spent nuclear fuel. The work and the results of the GPS deformation monitoring at Olkiluoto in 2013 are presented. The measurement consisted of two GPS measurement campaigns, observations at local permanent stations and control markers measurements at four stations. In spring six new stations were set up for permanent tracking. In total 12 permanent stations were operating continuously from April to the end of the year. The residual time series of the stations showed periodic trends up to 3 mm in height and 1 mm in horizontal component relative to the GPS1 station. A few stations were still measured as campaign-based and analysed baseline by baseline. The data from permanent stations (GPS1-GPS9, and GPS13) were included. The analysis of the inner network based on campaign sessions showed very small motions as in previous years: 75 % of change rates are smaller than 0.10 mm/y. Roughly one third of the change rates could be considered statistically significant at 1 % significance level. Statistically significant change rates were estimated for baselines from GPS1 and GPS5. The trends and strains differed at some baselines clearly from the earlier analysis because of different troposphere modelling. The results of the outer network showed the largest difference on the baseline GPS1-GPS11 where the trend decreased from -0.42 mm/y to -0.28 mm/y. The strain pattern of the outer network shows an eastwards motion of GPS1. The estimated strains for the baselines east of GPS1 were -0.03/-0.04 ppm/y. The control marker measurements were carried at the stations GPS1, GPS2, GPS4 and GPS6. A comparison of the results with the previous measurements showed that the distance between control markers at GPS6 continues to increase. Also

  19. PROPUESTA METODOLÓGICA PARA REALIZAR MAPAS DE CONOCIMIENTO

    Directory of Open Access Journals (Sweden)

    MARCO DUEÑAS

    2012-01-01

    Full Text Available Recientemente Chavalarias y Cointet (2008 propusieron una metodología para construir mapas de conocimiento. En dicho estudio el corpus de información se construye a partir de un conjunto de palabras clave fijas y determinadas de forma exógena. En este artículo se replica esta metodología, pero a diferencia, el conjunto de palabras clave es construido a través de búsquedas recurrentes y relacionadas. Así, iniciando con un conjunto reducido de palabras clave pertenecientes a un paradigma científico se construye un corpus de artículos, los cuales a su vez citan otras palabras clave que son usadas como insumo para una segunda búsqueda. Este estudio tomó como base artículos relacionados con aplicaciones satelitales. La metodología propuesta permite de igual forma construir mapas de conocimiento, o determinar los campos paradigmáticos (Chavalarias y Cointet, 2008, es decir se obtienen clusters conectados, compuestos de palabras relacionadas entre sí bajo un criterio específico de proximidad y de interrelación, que vistos de forma global permiten identificar áreas específicas del conocimiento.

  20. Applications of GPS technologies to field sports.

    Science.gov (United States)

    Aughey, Robert J

    2011-09-01

    Global positioning system (GPS) technology was made possible after the invention of the atomic clock. The first suggestion that GPS could be used to assess the physical activity of humans followed some 40 y later. There was a rapid uptake of GPS technology, with the literature concentrating on validation studies and the measurement of steady-state movement. The first attempts were made to validate GPS for field sport applications in 2006. While GPS has been validated for applications for team sports, some doubts continue to exist on the appropriateness of GPS for measuring short high-velocity movements. Thus, GPS has been applied extensively in Australian football, cricket, hockey, rugby union and league, and soccer. There is extensive information on the activity profile of athletes from field sports in the literature stemming from GPS, and this includes total distance covered by players and distance in velocity bands. Global positioning systems have also been applied to detect fatigue in matches, identify periods of most intense play, different activity profiles by position, competition level, and sport. More recent research has integrated GPS data with the physical capacity or fitness test score of athletes, game-specific tasks, or tactical or strategic information. The future of GPS analysis will involve further miniaturization of devices, longer battery life, and integration of other inertial sensor data to more effectively quantify the effort of athletes.

  1. GPS in Travel and Activity Surveys

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder

    2004-01-01

    The use of GPS-positioning as a monitoring tool in travel and activity surveys opens up a range of possibilities. Using a personal GPS device, the locations and movements of respondents can be followed over a longer period of time. It will then be possible to analyse how the use of urban spaces...... are embedded in the wider context of activity patterns (work, school etc.). The general pattern of everyday itineraries, including route choice and time spent at different locations ?on the way? can also be analysed. If the personal GPS device is combined with an electronic questionnaire, for example...... area. The paper presents the possibilities in travel and activity surveys with GPS and electronic questionnaires. Demonstrative mapping of test data from passive GPS registration of Copenhagen respondents is presented. The different survey possibilities given a combination of GPS and PDA based...

  2. Miniaturized GPS/MEMS IMU integrated board

    Science.gov (United States)

    Lin, Ching-Fang (Inventor)

    2012-01-01

    This invention documents the efforts on the research and development of a miniaturized GPS/MEMS IMU integrated navigation system. A miniaturized GPS/MEMS IMU integrated navigation system is presented; Laser Dynamic Range Imager (LDRI) based alignment algorithm for space applications is discussed. Two navigation cameras are also included to measure the range and range rate which can be integrated into the GPS/MEMS IMU system to enhance the navigation solution.

  3. GPS User Devices Parameter Control Methods

    OpenAIRE

    Klūga, A; Kuļikovs, M; Beļinska, V; Zeļenkovs, A

    2007-01-01

    In our day’s wide assortment of GPS user devices is manufacture. How to verify that parameters of the real device corresponds to parameters that manufacture shows. How to verify that parameters have not been changed during the operation time. The last one is very important for aviation GPS systems, which must be verified before the flight, but the values of parameter in time of repair works. This work analyses GPS user devices parameters control methods.

  4. The GPS Laser Retroreflector Array Project

    Science.gov (United States)

    Merkowitz, Stephen M.

    2012-01-01

    Systematic co-location in space through the precision orbit determination of GPS satellites via satellite laser ranging will contribute significantly towards improving the accuracy and stability of the international terrestrial reference frame. NASA recently formed the GPS Laser Retroreflector Array Project to develop and deliver retroreflectors for integration on the next generation of GPS satellites. These retroreflectors will be an important contributor to achieving a global accuracy of 1.0 mm and 0.1 mm/year stability in the international terrestrial reference frame. We report here the current status of the GPS Laser Retroreflector Array Project.

  5. GPS operations at Olkiluoto in 2009

    Energy Technology Data Exchange (ETDEWEB)

    Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M.; Ahola, J. (Finnish Geodetic Institute, Masala (Finland))

    2010-06-15

    The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. One pillar in the investigation area belongs to the Finnish permanent GPS network, FinnRef. 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than +-0.20 mm/a. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments in connection to the GPS observations. Changes in he difference between the GPS and EDM results indicate the systematic change in GPS results. No corrections based on only one baseline were not applied to GPS vectors. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003 and now we have computed the first deformation analysis from the six years data. Four new permanent stations will be established in summer 2010 at Olkiluoto. We have automated the processing of the campaign data by using the Bernese processing engine (BPE) together with our own Perl scripts. The local crustal deformations have been studied in GeoSatakunta project, too. This GPS network is located in Cities of Pori and Rauma and their neighbouring municipalities. Two new pillars

  6. GPS operations at Olkiluoto in 2009

    International Nuclear Information System (INIS)

    Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M.; Ahola, J.

    2010-06-01

    The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. One pillar in the investigation area belongs to the Finnish permanent GPS network, FinnRef. 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ±0.20 mm/a. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments in connection to the GPS observations. Changes in he difference between the GPS and EDM results indicate the systematic change in GPS results. No corrections based on only one baseline were not applied to GPS vectors. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003 and now we have computed the first deformation analysis from the six years data. Four new permanent stations will be established in summer 2010 at Olkiluoto. We have automated the processing of the campaign data by using the Bernese processing engine (BPE) together with our own Perl scripts. The local crustal deformations have been studied in GeoSatakunta project, too. This GPS network is located in Cities of Pori and Rauma and their neighbouring municipalities. Two new pillars

  7. GPS queues with heterogeneous traffic classes

    NARCIS (Netherlands)

    Borst, Sem; Mandjes, M.R.H.; van Uitert, Miranda

    2002-01-01

    We consider a queue fed by a mixture of light-tailed and heavy-tailed traffic. The two traffic classes are served in accordance with the generalized processor sharing (GPS) discipline. GPS-based scheduling algorithms, such as weighted fair queueing (WFQ), have emerged as an important mechanism for

  8. Convective towers detection using GPS radio occultations

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Neubert, Torsten; Syndergaard, S.

    the GPS signals penetrate through clouds and allow measurements of atmospheric profiles related to temperature, pressure, and water vapour with high vertical resolution. Using tropical cyclone best track database and data from different GPS RO missions (COSMIC, GRACE, CHAMP, SACC and GPSMET), we selected...

  9. Development of GPS survey data management protocols/policy.

    Science.gov (United States)

    2010-08-01

    This project developed a statewide policy and criteria for collecting, analyzing, and managing global position system (GPS) survey data. The research project determined the needs of the Department in adopting the GPS real time kinetic (GPS RTK) stake...

  10. Comparison of GLONASS and GPS Time Transfers

    Science.gov (United States)

    Daly, P.; Koshelyaevsky, N. B.; Lewandowski, W.; Petit, G.; Thomas, C.

    1993-01-01

    The Russian global space navigation system GLONASS could provide a technique similar to GPS for international time comparison. The main limitation to its use for time transfer is the lack of commercially available time receivers. The University of Leeds built a GPS/GLONASS receiver five years ago and since then has provided continuous information about GLONASS time and its comparison with GPS time. For the last two years the VNIIFTRI and several other Russian time laboratories have used Russian-built GLONASS navigation receivers for time comparisons. Since June 1991, the VNIIFTRI has operated a GPS time receiver which offers, for the first time, an opportunity for the direct comparison of time transfers using GPS and GLONASS. This seven-month experiment shows that even with relatively imprecise data recording and processing, in terms of time metrology, GLONASS can provide continental time transfer at a level of several tens of nanoseconds.

  11. GPS Precision Timing at CERN

    CERN Document Server

    Beetham, C G

    1999-01-01

    For the past decade, the Global Positioning System (GPS) has been used to provide precise time, frequency and position co-ordinates world-wide. Recently, equipment has become available specialising in providing extremely accurate timing information, referenced to Universal Time Co-ordinates (UTC). This feature has been used at CERN to provide time of day information for systems that have been installed in the Proton Synchrotron (PS), Super Proton Synchrotron (SPS) and the Large Electron Positron (LEP) machines. The different systems are described as well as the planned developments, particularly with respect to optical transmission and the Inter-Range Instrumentation Group IRIG-B standard, for future use in the Large Hadron Collider (LHC).

  12. Briefing highlights space weather risks to GPS

    Science.gov (United States)

    Tretkoff, Ernie

    2011-07-01

    Solar storms, which are expected to increase as the Sun nears the most active phase of the solar cycle, can disrupt a variety of technologies on which society relies. Speakers at a 22 June briefing on Capitol Hill in Washington, D. C., focused on how space weather can affect the Global Positioning System (GPS), which is used in a wide range of industries, including commercial air travel, agriculture, national security, and emergency response. Rocky Stone, chief technical pilot for United Airlines, noted that GPS allows more aircraft to be in airspace, saves fuel, and helps aircraft move safely on runways. “Improvements in space weather forecasting need to be pursued,” he said. Precision GPS has also “changed the whole nature of farming,” said Ron Hatch, Director of Navigation Systems, NavCom Technology/John Deere. GPS makes it possible for tractors to be driven in the most efficient paths and for fertilizer and water to be applied precisely to the areas that most need them. Space weather-induced degradation of GPS signals can cause significant loss to farms that rely on GPS. Elizabeth Zimmerman, Deputy Associate Administrator for the Office of Response and Recovery at the Federal Emergency Management Agency (FEMA), described how FEMA relies on GPS for disaster recovery. The agency is developing an operations plan for dealing with space weather, she said.

  13. Robust GPS autonomous signal quality monitoring

    Science.gov (United States)

    Ndili, Awele Nnaemeka

    The Global Positioning System (GPS), introduced by the U.S. Department of Defense in 1973, provides unprecedented world-wide navigation capabilities through a constellation of 24 satellites in global orbit, each emitting a low-power radio-frequency signal for ranging. GPS receivers track these transmitted signals, computing position to within 30 meters from range measurements made to four satellites. GPS has a wide range of applications, including aircraft, marine and land vehicle navigation. Each application places demands on GPS for various levels of accuracy, integrity, system availability and continuity of service. Radio frequency interference (RFI), which results from natural sources such as TV/FM harmonics, radar or Mobile Satellite Systems (MSS), presents a challenge in the use of GPS, by posing a threat to the accuracy, integrity and availability of the GPS navigation solution. In order to use GPS for integrity-sensitive applications, it is therefore necessary to monitor the quality of the received signal, with the objective of promptly detecting the presence of RFI, and thus provide a timely warning of degradation of system accuracy. This presents a challenge, since the myriad kinds of RFI affect the GPS receiver in different ways. What is required then, is a robust method of detecting GPS accuracy degradation, which is effective regardless of the origin of the threat. This dissertation presents a new method of robust signal quality monitoring for GPS. Algorithms for receiver autonomous interference detection and integrity monitoring are demonstrated. Candidate test statistics are derived from fundamental receiver measurements of in-phase and quadrature correlation outputs, and the gain of the Active Gain Controller (AGC). Performance of selected test statistics are evaluated in the presence of RFI: broadband interference, pulsed and non-pulsed interference, coherent CW at different frequencies; and non-RFI: GPS signal fading due to physical blockage and

  14. Mining Significant Semantic Locations from GPS Data

    DEFF Research Database (Denmark)

    Cao, Xin; Cong, Gao; Jensen, Christian Søndergaard

    2010-01-01

    With the increasing deployment and use of GPS-enabled devices, massive amounts of GPS data are becoming available. We propose a general framework for the mining of semantically meaningful, significant locations, e.g., shopping malls and restaurants, from such data. We present techniques capable...... of extracting semantic locations from GPS data. We capture the relationships between locations and between locations and users with a graph. Significance is then assigned to locations using random walks over the graph that propagates significance among the locations. In doing so, mutual reinforcement between...

  15. Mining significant semantic locations from GPS data

    DEFF Research Database (Denmark)

    Cao, Xin; Cong, Gao; Jensen, Christian S.

    2010-01-01

    With the increasing deployment and use of GPS-enabled devices, massive amounts of GPS data are becoming available. We propose a general framework for the mining of semantically meaningful, significant locations, e.g., shopping malls and restaurants, from such data. We present techniques capable...... of extracting semantic locations from GPS data. We capture the relationships between locations and between locations and users with a graph. Significance is then assigned to locations using random walks over the graph that propagates significance among the locations. In doing so, mutual reinforcement between...

  16. LADOTD GPS technology management plan : tech summary.

    Science.gov (United States)

    2012-02-01

    Global Positioning System (GPS) technology has been adopted by diff erent sections within the Louisiana : Department of Transportation and Development (LADOTD) over the last decade with no uniform standards : for their use, procurement, training, and...

  17. Overview of GPS Adjacent Band Compatibility Assessment

    Science.gov (United States)

    2014-09-18

    January 13, 2012 National SpaceBased Positioning, Navigation, and Timing (PNT) Executive Committee (EXCOM) cochair letter to National Telecommunications and Information Administration (NTIA) proposed to draft new Global Positioning System (GPS)...

  18. Ionospheric irregularities at Antarctic using GPS measurements

    Indian Academy of Sciences (India)

    Scintillation is a major problem in navigation application using GPS and in satellite ... ground ionization which leads to phase as well as amplitude scintillation as reported by ..... in satellite sig- nals which arise from the scattering of radio waves.

  19. Global Positioning System (GPS) Energetic Particle Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Energetic particle data from the CXD and BDD instrument on the GPS constellation are available to the space weather research community. The release of these data...

  20. Real-time GPS Signal Simulator

    Data.gov (United States)

    National Aeronautics and Space Administration — With a minimal FTE investment and no additional procurement funds, the development of a low fidelity orbital GPS Signal simulator would is possible.  This IRAD...

  1. GPS-deprived localisation for underground mines

    CSIR Research Space (South Africa)

    Hlophe, K

    2010-08-31

    Full Text Available robots. Opencast mines utilise the global positioning system (GPS) to obtain location information. The unavailability of this technology in underground mining has actuated numerous researchers to investigate possible alternatives. These attempts exploit...

  2. En Billig GPS Data Analyse Platform

    DEFF Research Database (Denmark)

    Andersen, Ove; Christiansen, Nick; Larsen, Niels T.

    2011-01-01

    Denne artikel præsenterer en komplet software platform til analyse af GPS data. Platformen er bygget udelukkende vha. open-source komponenter. De enkelte komponenter i platformen beskrives i detaljer. Fordele og ulemper ved at bruge open-source diskuteres herunder hvilke IT politiske tiltage, der...... organisationer med et digitalt vejkort og GPS data begynde at lave trafikanalyser på disse data. Det er et krav, at der er passende IT kompetencer tilstede i organisationen....

  3. AVALIAÇÃO DO DESEMPENHO DOS SISTEMAS GPS E GLONASS NO POSICIONAMENTO POR PONTO PRECISO, COMBINADOS E INDIVIDUALMENTE.

    Directory of Open Access Journals (Sweden)

    Bruno Guimarães Ventorim

    Full Text Available Este trabalho visa avaliar o desempenho dos sistemas GLONASS (Global'naya Navigatsionnay Sputnikovaya Sistema, GPS (Global Positioning System e o uso combinado de ambos sistemas em diferentes latitudes, utilizando o serviço de Posicionamento por Ponto Preciso CSRS-PPP. Para isso foram selecionadas 16 estações da rede IGS (International GNSS Service, das quais foram utilizados os dados GNSS no formato RINEX do mês de agosto de 2014 e editados no TEQC (Translation, Editing, and Quality Check, obtendo arquivos com intervalos de 30 e 45 minutos, contendo apenas dados GPS, dados GLONASS e dados dos dois sistemas. As coordenadas estimadas no CSRS-PPP foram comparadas com as coordenadas de referência obtidas no sítio do ITRF (International Terrestrial Reference Frame, possibilitando o cálculo da acurácia do PPP com uso de dados GPS e GLONASS, separadamente e em conjunto. Após o cálculo das acurácias para cada dia de agosto, outliers foram detectados e eliminados utilizando o método boxplot com o uso do programa R. Verificou-se que o uso combinado do GPS e GLONASS, para todos as estações, proporcionou resultados mais acurados. Além disso, pode-se destacar a potencialidade do GLONASS, que apresentou desempenho superior ao do GPS na maioria das estações.

  4. Assessing fitness for work: GPs judgment making.

    Science.gov (United States)

    Foley, Michelle; Thorley, Kevan; Van Hout, Marie-Claire

    2013-12-01

    The complexity of a fitness for work consultation is well documented. General practitioners (GPs) find that such consultations often create conflict and they feel ill-prepared for the task. We aimed to examine the consultation process in the fitness for work consultation and to report on the response of GPs to two hypothetical consultations of work related sickness absence, one of a psychological and one of a physical nature. Three areas of the consultation were examined; social/family circumstances, workplace history and information required assessing the severity of the condition. We used a randomized design using an online questionnaire completed by 62 GPs located in the Republic of Ireland. Analysis was conducted in NVivo 8 qualitative software using thematic and content analysis techniques. GPs may be expected to collect and consider information relating to social, domestic, financial, lifestyle and workplace factors, including workload, job satisfaction, job strain, work ethic, inter staff relationships and employee support mechanisms. The mode of presentation may trigger specific information seeking in the consultation. GPs may evaluate fitness for work in a variety of ways depending on medical and non-medical factors. Further research should further examine the factors that may influence the GPs decision to prescribe sickness leave.

  5. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao

    2009-05-01

    Full Text Available The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena.

    Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB L-band scintillation events, adversely affecting the GPS based navigation.

  6. Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

    Science.gov (United States)

    Pan, Lin; Cai, Changsheng; Santerre, Rock; Zhu, Jianjun

    2014-01-01

    Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF. PMID:25237901

  7. Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities

    Directory of Open Access Journals (Sweden)

    Lin Pan

    2014-09-01

    Full Text Available Precise point positioning (PPP technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF. All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF.

  8. The International GPS Service (IGS) as a Continuous Reference System for Precise GPS Positioning

    Science.gov (United States)

    Neilan, Ruth; Heflin, Michael; Watkins, Michael; Zumberge, James

    1996-01-01

    The International GPS Service for Geodynamics (IGS) is an organization which operates under the auspices of the International Association of Geodesy (IAG) and has been operational since January 1994. The primary objective of the IGS is to provide precise GPS data and data products to support geodetic and geophysical research activities.

  9. GPS Space Service Volume: Ensuring Consistent Utility Across GPS Design Builds for Space Users

    Science.gov (United States)

    Bauer, Frank H.; Parker, Joel Jefferson Konkl; Valdez, Jennifer Ellen

    2015-01-01

    GPS availability and signal strength originally specified for users on or near surface of Earth with transmitted power levels specified at edge-of-Earth, 14.3 degrees. Prior to the SSV specification, on-orbit performance of GPS varied from block build to block build (IIA, IIRM, IIF) due to antenna gain and beam width variances. Unstable on-orbit performance results in significant risk to space users. Side-lobe signals, although not specified, were expected to significantly boost GPS signal availability for users above the constellation. During GPS III Phase A, NASA noted significant discrepancies in power levels specified in GPS III specification documents, and measured on-orbit performance. To stabilize the signal for high altitude space users, NASA DoD team in 2003-2005 led the creation of new Space Service Volume (SSV) definition and specifications.

  10. Mobilidades cotidianas das crianças: combinando etnografia, gps e tecnologias de telefone móvel em pesquisa

    DEFF Research Database (Denmark)

    Christensen, Pia Hartrup; Mikkelsen, Miguel Romero; Nielsen, Thomas Alexander Sick

    2014-01-01

    Este artigo discute o desenvolvimento de uma abordagem com métodos mistos para o estudo da mobilidade diária das crianças. O estudo aqui apresentado combinou pesquisa etnográfica com a tecnologia de GPS ( Global Positioning System ) e um questionário interativo que as crianças completaram via...

  11. GPS Tomography: Water Vapour Monitoring for Germany

    Science.gov (United States)

    Bender, Michael; Dick, Galina; Wickert, Jens; Raabe, Armin

    2010-05-01

    Ground based GPS atmosphere sounding provides numerous atmospheric quantities with a high temporal resolution for all weather conditions. The spatial resolution of the GPS observations is mainly given by the number of GNSS satellites and GPS ground stations. The latter could considerably be increased in the last few years leading to more reliable and better resolved GPS products. New techniques such as the GPS water vapour tomography gain increased significance as data from large and dense GPS networks become available. The GPS tomography has the potential to provide spatially resolved fields of different quantities operationally, i. e. the humidity or wet refractivity as required for meteorological applications or the refraction index which is important for several space based observations or for precise positioning. The number of German GPS stations operationally processed by the GFZ in Potsdam was recently enlarged to more than 300. About 28000 IWV observations and more than 1.4 millions of slant total delay data are now available per day with a temporal resolution of 15 min and 2.5 min, respectively. The extended network leads not only to a higher spatial resolution of the tomographically reconstructed 3D fields but also to a much higher stability of the inversion process and with that to an increased quality of the results. Under these improved conditions the GPS tomography can operate continuously over several days or weeks without applying too tight constraints. Time series of tomographically reconstructed humidity fields will be shown and different initialisation strategies will be discussed: Initialisation with a simple exponential profile, with a 3D humidity field extrapolated from synoptic observations and with the result of the preceeding reconstruction. The results are compared to tomographic reconstructions initialised with COSMO-DE analyses and to the corresponding model fields. The inversion can be further stabilised by making use of independent

  12. Development of automatic techniques for GPS data management

    International Nuclear Information System (INIS)

    Park, Pil Ho

    2001-06-01

    It is necessary for GPS center to establish automatization as effective management of GPS network including data gathering, data transformation, data backup, data sending to IGS (International GPS Service for geodynamics), and precise ephemerides gathering. The operating program of GPS center has been adopted at KCSC (Korea Cadastral Survey Corporation), NGI (National Geography Institute), MOMAF (Ministry of Maritime Affairs and Fisheries) without self-development of core technique. The automatic management of GPS network is consists of GPS data management and data processing. It is also fundamental technique, which should be accomplished by every GPS centers. Therefore, this study carried out analyzing of Japanese GPS center, which has accomplished automatization by module considering applicability for domestic GPS centers

  13. Physical applications of GPS geodesy: a review.

    Science.gov (United States)

    Bock, Yehuda; Melgar, Diego

    2016-10-01

    Geodesy, the oldest science, has become an important discipline in the geosciences, in large part by enhancing Global Positioning System (GPS) capabilities over the last 35 years well beyond the satellite constellation's original design. The ability of GPS geodesy to estimate 3D positions with millimeter-level precision with respect to a global terrestrial reference frame has contributed to significant advances in geophysics, seismology, atmospheric science, hydrology, and natural hazard science. Monitoring the changes in the positions or trajectories of GPS instruments on the Earth's land and water surfaces, in the atmosphere, or in space, is important for both theory and applications, from an improved understanding of tectonic and magmatic processes to developing systems for mitigating the impact of natural hazards on society and the environment. Besides accurate positioning, all disturbances in the propagation of the transmitted GPS radio signals from satellite to receiver are mined for information, from troposphere and ionosphere delays for weather, climate, and natural hazard applications, to disturbances in the signals due to multipath reflections from the solid ground, water, and ice for environmental applications. We review the relevant concepts of geodetic theory, data analysis, and physical modeling for a myriad of processes at multiple spatial and temporal scales, and discuss the extensive global infrastructure that has been built to support GPS geodesy consisting of thousands of continuously operating stations. We also discuss the integration of heterogeneous and complementary data sets from geodesy, seismology, and geology, focusing on crustal deformation applications and early warning systems for natural hazards.

  14. Uso de imágenes satelitales de alta resolución en el estudio de los bosques: análisis bibliométrico a través de Web of Science (1985-2015)

    OpenAIRE

    Fontans, Exequiel; Sosa, Beatriz Soledad; Achkar, Marcel

    2015-01-01

    Las técnicas de teledetección constituyen una herramienta indispensable para caracterizar los tipos de hábitat en áreas extensas y detectar los cambios ambientales resultantes de los procesos naturales y las actividades antrópicas. Estas potencialidades se incrementaron con el lanzamiento de los satélites de alta resolución espacial. En este marco constituye una herramienta de análisis para varias disciplinas como la gestión del territorio, la ecología y la conservación. Actualmente los ec...

  15. Análisis de series temporales en estaciones permanentes GPS

    OpenAIRE

    García Cañada, Laura

    2016-01-01

    En los ultimos años el número de estaciones permanentes GPS ha aumentado considerablemente para diferentes aplicaciones geodésicas y se comienza a disponer de series de coordenadas suficientemente largas como para poder aplicar ánalisis de series temporales. El principal objetivo de esta tesis es estudiar la influencia de la red de estaciones utilizada, marco de referencia y/o estrategia de procesado en las series temporales de coordenadas de estaciones CGPS y todos aquellos parámetros que se...

  16. Análisis de series temporales en estaciones permanentes GPS

    OpenAIRE

    García Cañada, Laura

    2015-01-01

    En los ultimos años el número de estaciones permanentes GPS ha aumentado considerablemente para diferentes aplicaciones geodésicas y se comienza a disponer de series de coordenadas suficientemente largas como para poder aplicar ánalisis de series temporales. El principal objetivo de esta tesis es estudiar la influencia de la red de estaciones utilizada, marco de referencia y/o estrategia de procesado en las series temporales de coordenadas de estaciones CGPS y todos aquellos parámetros que s...

  17. Single-Receiver GPS Phase Bias Resolution

    Science.gov (United States)

    Bertiger, William I.; Haines, Bruce J.; Weiss, Jan P.; Harvey, Nathaniel E.

    2010-01-01

    Existing software has been modified to yield the benefits of integer fixed double-differenced GPS-phased ambiguities when processing data from a single GPS receiver with no access to any other GPS receiver data. When the double-differenced combination of phase biases can be fixed reliably, a significant improvement in solution accuracy is obtained. This innovation uses a large global set of GPS receivers (40 to 80 receivers) to solve for the GPS satellite orbits and clocks (along with any other parameters). In this process, integer ambiguities are fixed and information on the ambiguity constraints is saved. For each GPS transmitter/receiver pair, the process saves the arc start and stop times, the wide-lane average value for the arc, the standard deviation of the wide lane, and the dual-frequency phase bias after bias fixing for the arc. The second step of the process uses the orbit and clock information, the bias information from the global solution, and only data from the single receiver to resolve double-differenced phase combinations. It is called "resolved" instead of "fixed" because constraints are introduced into the problem with a finite data weight to better account for possible errors. A receiver in orbit has much shorter continuous passes of data than a receiver fixed to the Earth. The method has parameters to account for this. In particular, differences in drifting wide-lane values must be handled differently. The first step of the process is automated, using two JPL software sets, Longarc and Gipsy-Oasis. The resulting orbit/clock and bias information files are posted on anonymous ftp for use by any licensed Gipsy-Oasis user. The second step is implemented in the Gipsy-Oasis executable, gd2p.pl, which automates the entire process, including fetching the information from anonymous ftp

  18. Combining GPS measurements and IRI model predictions

    International Nuclear Information System (INIS)

    Hernandez-Pajares, M.; Juan, J.M.; Sanz, J.; Bilitza, D.

    2002-01-01

    The free electrons distributed in the ionosphere (between one hundred and thousands of km in height) produce a frequency-dependent effect on Global Positioning System (GPS) signals: a delay in the pseudo-orange and an advance in the carrier phase. These effects are proportional to the columnar electron density between the satellite and receiver, i.e. the integrated electron density along the ray path. Global ionospheric TEC (total electron content) maps can be obtained with GPS data from a network of ground IGS (international GPS service) reference stations with an accuracy of few TEC units. The comparison with the TOPEX TEC, mainly measured over the oceans far from the IGS stations, shows a mean bias and standard deviation of about 2 and 5 TECUs respectively. The discrepancies between the STEC predictions and the observed values show an RMS typically below 5 TECUs (which also includes the alignment code noise). he existence of a growing database 2-hourly global TEC maps and with resolution of 5x2.5 degrees in longitude and latitude can be used to improve the IRI prediction capability of the TEC. When the IRI predictions and the GPS estimations are compared for a three month period around the Solar Maximum, they are in good agreement for middle latitudes. An over-determination of IRI TEC has been found at the extreme latitudes, the IRI predictions being, typically two times higher than the GPS estimations. Finally, local fits of the IRI model can be done by tuning the SSN from STEC GPS observations

  19. A Bridge Deflection Monitoring with GPS

    Science.gov (United States)

    Figurski, M.; Gałuszkiewicz, M.; Wrona, M.

    2007-01-01

    This paper introduces results of investigation carried on by The Applied Geomatics Section in Military University of Technology. Research includes possibilities of monitoring dynamic behavior of a bridge using high rate GPS data. Whole event was executed with collaboration of The Road and Bridge Management and The Warsaw Geodesy Company. Interdisciplinary approach with this project allows authors to get reliable information about investigating constructions and their respond for true traffic loading detected by GPS receivers. Way of compute data and used software (TRACK) are also shown in this paper.

  20. GPS synchronized power system phase angle measurements

    Science.gov (United States)

    Wilson, Robert E.; Sterlina, Patrick S.

    1994-09-01

    This paper discusses the use of Global Positioning System (GPS) synchronized equipment for the measurement and analysis of key power system quantities. Two GPS synchronized phasor measurement units (PMU) were installed before testing. It was indicated that PMUs recorded the dynamic response of the power system phase angles when the northern California power grid was excited by the artificial short circuits. Power system planning engineers perform detailed computer generated simulations of the dynamic response of the power system to naturally occurring short circuits. The computer simulations use models of transmission lines, transformers, circuit breakers, and other high voltage components. This work will compare computer simulations of the same event with field measurement.

  1. Effect of GPS errors on Emission model

    DEFF Research Database (Denmark)

    Lehmann, Anders; Gross, Allan

    n this paper we will show how Global Positioning Services (GPS) data obtained from smartphones can be used to model air quality in urban settings. The paper examines the uncertainty of smartphone location utilising GPS, and ties this location uncertainty to air quality models. The results presented...... in this paper indicates that the location error from using smartphones is within the accuracy needed to use the location data in air quality modelling. The nature of smartphone location data enables more accurate and near real time air quality modelling and monitoring. The location data is harvested from user...

  2. APPLICATION OF GPS AND GIS TO STUDY FORAGING BEHAVIOR OF DAIRY CATTLE

    Directory of Open Access Journals (Sweden)

    Jairo Mora-Delgado

    2016-01-01

    Full Text Available Se evaluó el uso de los Sistemas de Posicionamiento Global (GPS para discriminar las actividades de pastoreo de vacas lecheras. El estudio se realizó en la granja robotizada de la Estación Biológica WK Kellogg de la Universi-dad Estatal de Michigan, entre 11 y 20 de agosto, 2010. Mediante observación de las actividades de forrajeo en diferentes sitios, usando sensores remotos se llevó un registro de la actividad de 4 vacas lactantes Holstein (650 kg PV; 23 kg.día-1 equipadas con collares GPS, que registran la posición de la cabeza con sensores de mov-imiento para los ejes X y Y. Los GPS mostraron 82-86% de probabilidad que la estimación de las ubicaciones de los animales tuviesen un error de 7 m. Estos datos sugirieron que las vacas permanecieron en las pasturas la mayor parte del tiempo (94,6±0,92% y dentro del establo sólo un 5,4% (±0,92 del tiempo. Cuando las vacas esta-ban en las pasturas, la mayor parte del tiempo la dedicaron a pastoreo (51%; otra parte se dedicó a reposo (43% y 6% a traslado. El ganado viajó en promedio 3385±712 m por día. En días de tem-peratura baja la actividad principal de las vacas fue el pastoreo (92% y en días de media y alta temperatura el pastoreo fue sólo 62,6 y 59,4%, respectivamente. Por el contrario, el reposo fue la actividad más importante bajo media y alta temperatura (33,6 y 31,8%, respectivamente. Se demostró la utilidad de la teledetección y los GPS para monitorear el comportamiento animal.

  3. USGS Earthquake Program GPS Use Case : Earthquake Early Warning

    Science.gov (United States)

    2015-03-12

    USGS GPS receiver use case. Item 1 - High Precision User (federal agency with Stafford Act hazard alert responsibilities for earthquakes, volcanoes and landslides nationwide). Item 2 - Description of Associated GPS Application(s): The USGS Eart...

  4. GPS Attitude Determination for Launch Vehicles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Toyon Research Corporation proposes to develop a family of compact, low-cost GPS-based attitude (GPS/A) sensors for launch vehicles. In order to obtain 3-D attitude...

  5. IceBridge GPS L0 Raw Satellite Navigation Data

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge GPS L0 Raw Satellite Navigation Data (IPUTG0) data set contains GPS readings, including latitude, longitude, track, ground speed, off distance,...

  6. Derivation of some geometric parameters from GPS measurements

    Directory of Open Access Journals (Sweden)

    Marcel Mojzeš

    2005-11-01

    Full Text Available Combining GPS and terrestrial data requires a common coordinate system. When the original GPS vectors do not form a network, the 3D network adjustment can not be performed. In this case, in order to integrate the GPS measurements with the terrestrial observations and to perform a combined network adjustment, the GPS measurements should be transformed to this common system. The GPS measurements which are the usual output of the GPS post processing softwares are based on the WGS84 ellipsoid and the S-JTSK local datum is based on the Bessel ellipsoid. Thus, the reduction of measurements to the S-JTSK mapping plane can not be started from the measurements resulting from GPS post processing softwares because GPS and S-JTSK don’t have the same ellipsoid. Another view of this reduction will be described in this paper.

  7. Using GPS for studying pastoral mobility

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2017-01-01

    geographer familiar with satellite remote sensing and GIS, I pondered how these relatively new technologies could be combined with classic ethnographic fieldwork, which we also use in human geography. I decided to use handheld GPS devices for tracking the pastoralists and their herds. My study was, as far...... the interviewee’s point of view....

  8. The covariance of GPS coordinates and frames

    International Nuclear Information System (INIS)

    Lachieze-Rey, Marc

    2006-01-01

    We explore, in the general relativistic context, the properties of the recently introduced global positioning system (GPS) coordinates, as well as those of the associated frames and coframes that they define. We show that they are covariant and completely independent of any observer. We show that standard spectroscopic and astrometric observations allow any observer to measure (i) the values of the GPS coordinates at his position (ii) the components of his 4-velocity and (iii) the components of the metric in the GPS frame. This provides this system with a unique value both for conceptual discussion (no frame dependence) and for practical use (involved quantities are directly measurable): localization, motion monitoring, astrometry, cosmography and tests of gravitation theories. We show explicitly, in the general relativistic context, how an observer may estimate his position and motion, and reconstruct the components of the metric. This arises from two main results: the extension of the velocity fields of the probes to the whole (curved) spacetime, and the identification of the components of the observer's velocity in the GPS frame with the (inversed) observed redshifts of the probes. Specific cases (non-relativistic velocities, Minkowski and Friedmann-Lemaitre spacetimes, geodesic motions) are studied in detail

  9. Characterizing urban structure using taxi GPS data

    NARCIS (Netherlands)

    Zheng, Zhong; Zhou, Suhong; Rasouli, S.; Timmermans, H.J.P.

    2014-01-01

    Scholars have explored urban structure from many perspectives. Developments in ICT have made it possible to discover spatial patterns in activities using big data. The identified patterns allow us to better understand urban structure. This chapter reports the collection of taxi GPS records for a

  10. Integrating GPS with Dead Reckoning Sensors

    DEFF Research Database (Denmark)

    Cederholm, Jens Peter

    2000-01-01

    A vehicle positioning system comprising a GPS receiver, a digital compass, and an odometer was tested on a 2.8-km stretch in Aalborg, Denmark. The system, which merges observations from the three instruments using a Kalman filter, has an update rate of 1 Hz and is intended for use in both urban a...

  11. Fundamentals of GPS Receivers A Hardware Approach

    CERN Document Server

    Doberstein, Dan

    2012-01-01

    While much of the current literature on GPS receivers is aimed at those intimately familiar with their workings, this volume summarizes the basic principles using as little mathematics as possible, and details the necessary specifications and circuits for constructing a GPS receiver that is accurate to within 300 meters. Dedicated sections deal with the features of the GPS signal and its data stream, the details of the receiver (using a hybrid design as exemplar), and more advanced receivers and topics including time and frequency measurements. Later segments discuss the Zarlink GPS receiver chip set, as well as providing a thorough examination of the TurboRogue receiver, one of the most accurate yet made. Guiding the reader through the concepts and circuitry, from the antenna to the solution of user position, the book’s deployment of a hybrid receiver as a basis for discussion allows for extrapolation of the core ideas to more complex, and more accurate designs. Digital methods are used, but any analogue c...

  12. Exploring female GPs' perceptions about medical leadership.

    Science.gov (United States)

    Price, Karen; Clearihan, Lynette

    2015-06-01

    Women are increasingly entering the Australian general practice workforce. This study aims to explore female general practitioners' (GPs') perceptions of possible barriers to leadership and professional roles in the workforce. A purposive, convenience sample of 30 female GPs in active practice was approached in February, 2012. An anonymous, pa-per-based, semi-quantitative survey sought to identify participation and leadership confidence within general practice in a number of professional roles. The top two barriers participants identified for after-hours medical meetings were energy to attend and geographical location. For after-hours care, the top two barriers identified were energy and self-motivation. Few participants aspired to 'leadership' activities. 'Medical mentoring' was most likely to attract them into leadership. It is important female GPs' perspectives are explored in general practice. This small survey suggests further studies are needed in the importance of energy limitations and lack of self-confidence in restricting female GPs' capacity to fully engage in professional roles.

  13. TLALOCNet continuous GPS-Met Array in Mexico supporting the 2017 NAM GPS Hydrometeorological Network.

    Science.gov (United States)

    Cabral-Cano, E.; Salazar-Tlaczani, L.; Adams, D. K.; Vivoni, E. R.; Grutter, M.; Serra, Y. L.; DeMets, C.; Galetzka, J.; Feaux, K.; Mattioli, G. S.; Miller, M. M.

    2017-12-01

    TLALOCNet is a network of continuous GPS and meteorology stations in Mexico to study atmospheric and solid earth processes. This recently completed network spans most of Mexico with a strong coverage emphasis on southern and western Mexico. This network, funded by NSF, CONACyT and UNAM, recently built 40 cGPS-Met sites to EarthScope Plate Boundary Observatory standards and upgraded 25 additional GPS stations. TLALOCNet provides open and freely available raw GPS data, and high frequency surface meteorology measurements, and time series of daily positions. This is accomplished through the development of the TLALOCNet data center (http://tlalocnet.udg.mx) that serves as a collection and distribution point. This data center is based on UNAVCO's Dataworks-GSAC software and also works as part of UNAVCO's seamless archive for discovery, sharing, and access to GPS data. The TLALOCNet data center also contains contributed data from several regional GPS networks in Mexico for a total of 100+ stations. By using the same protocols and structure as the UNAVCO and other COCONet regional data centers, the scientific community has the capability of accessing data from the largest Mexican GPS network. This archive provides a fully queryable and scriptable GPS and Meteorological data retrieval point. In addition, real-time 1Hz streams from selected TLALOCNet stations are available in BINEX, RTCM 2.3 and RTCM 3.1 formats via the Networked Transport of RTCM via Internet Protocol (NTRIP) for real-time seismic and weather forecasting applications. TLALOCNet served as a GPS-Met backbone for the binational Mexico-US North American Monsoon GPS Hydrometeorological Network 2017 campaign experiment. This innovative experiment attempts to address water vapor source regions and land-surface water vapor flux contributions to precipitation (i.e., moisture recycling) during the 2017 North American Monsoon in Baja California, Sonora, Chihuahua, and Arizona. Models suggest that moisture recycling is

  14. How does the workload and work activities of procedural GPs compare to non-procedural GPs?

    Science.gov (United States)

    Russell, Deborah J; McGrail, Matthew R

    2017-08-01

    To investigate patterns of Australian GP procedural activity and associations with: geographical remoteness and population size hours worked in hospitals and in total; and availability for on-call DESIGN AND PARTICIPANTS: National annual panel survey (Medicine in Australia: Balancing Employment and Life) of Australian GPs, 2011-2013. Self-reported geographical work location, hours worked in different settings, and on-call availability per usual week, were analysed against GP procedural activity in anaesthetics, obstetrics, surgery or emergency medicine. Analysis of 9301 survey responses from 4638 individual GPs revealed significantly increased odds of GP procedural activity in anaesthetics, obstetrics or emergency medicine as geographical remoteness increased and community population size decreased, albeit with plateauing of the effect-size from medium-sized (population 5000-15 000) rural communities. After adjusting for confounders, procedural GPs work more hospital and more total hours each week than non-procedural GPs. In 2011 this equated to GPs practising anaesthetics, obstetrics, surgery, and emergency medicine providing 8% (95%CI 0, 16), 13% (95%CI 8, 19), 8% (95%CI 2, 15) and 18% (95%CI 13, 23) more total hours each week, respectively. The extra hours are attributable to longer hours worked in hospital settings, with no reduction in private consultation hours. Procedural GPs also carry a significantly higher burden of on-call. The longer working hours and higher on-call demands experienced by rural and remote procedural GPs demand improved solutions, such as changes to service delivery models, so that long-term procedural GP careers are increasingly attractive to current and aspiring rural GPs. © 2016 National Rural Health Alliance Inc.

  15. 77 FR 70421 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2012-11-26

    ... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Department of the Air Force, DoD. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS...

  16. 78 FR 63459 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-10-24

    ... DEPARTMENT OF DEFENSE Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Department of the Air Force. ACTION: Meeting Notice. SUMMARY: This meeting notice is to inform GPS simulator manufacturers, who supply products to the Department of Defense (DoD), and GPS simulator users, both government...

  17. The Evolution of Global Positioning System (GPS) Technology.

    Science.gov (United States)

    Kumar, Sameer; Moore, Kevin B.

    2002-01-01

    Describes technological advances in the Global Positioning System (GPS), which is also known as the NAVSTAR GPS satellite constellation program developed in 1937, and changes in the nature of our world by GPS in the areas of agriculture, health, military, transportation, environment, wildlife biology, surveying and mapping, space applications, and…

  18. Transportation mode recognition using GPS and accelerometer data

    NARCIS (Netherlands)

    Feng, T.; Timmermans, H.J.P.

    2013-01-01

    Potential advantages of global positioning systems (GPS) in collecting travel behavior data have been discussed in several publications and evidenced in many recent studies. Most applications depend on GPS information only. However, transportation mode detection that relies only on GPS information

  19. Sensing and Classifying Impairments of GPS Reception on Mobile Devices

    DEFF Research Database (Denmark)

    Blunck, Henrik; Kjærgaard, Mikkel Baun; Toftegaard, Thomas Skjødeberg

    2011-01-01

    Positioning using GPS receivers is a primary sensing modality in many areas of pervasive computing. However, previous work has not considered how people’s body impacts the availability and accuracy of GPS positioning and for means to sense such impacts. We present results that the GPS performance...

  20. GPS-derived crustal deformation in Azerbaijan

    Science.gov (United States)

    Safarov, Rafig; Mammadov, Samir; Kadirov, Fakhraddin

    2017-04-01

    Crustal deformations of the Earth's crust in Azerbaijan were studied based on GPS measurements. The GPS velocity vectors for Azerbaijan, Iran, Georgia, and Armenia were used in order to estimate the deformation rates. It is found that compression is observable along the Greater Caucasus, in Gobustan, the Kura depression, Nakhchyvan Autonomous Republic, and adjacent areas of Iran. The axes of compression/contraction of the crust in the Greater Caucasus region are oriented in the S-NE direction. The maximum strain rate is observed in the zone of mud volcanism at the SHIK site (Shykhlar), which is marked by a sharp change in the direction of the compression axes (SW-NE). It is revealed that the deformation field also includes the zones where strain rates are very low. These zones include the Caspian-Guba and northern Gobustan areas, characterized by extensive development of mud volcanism. The extension zones are confined to the Lesser Caucasus and are revealed in the Gyadabei (GEDA) and Shusha (SHOU) areas. The analysis of GPS data for the territory of Azerbaijan and neighboring countries reveals the heterogeneous patterns of strain field in the region. This fact suggests that the block model is most adequate for describing the structure of the studied region. The increase in the number of GPS stations would promote increasing the degree of detail in the reconstructions of the deformation field and identifying the microplate boundaries.It is concluded that the predominant factor responsible for the eruption of mud volcanoes is the intensity of gasgeneration processes in the earth's interior, while deformation processes play the role of a trigger. The zone of the epicenters of strong earthquakes is correlated to the gradient zone in the crustal strain rates.

  1. Global Geodesy Using GPS Without Fiducial Sites

    Science.gov (United States)

    Heflin, Michael B.; Blewitt, Geoffrey

    1994-01-01

    Global Positioning System, GPS, used to make global geodetic measurements without use of fiducial site coordinates. Baseline lengths and geocentric radii for each site determined without having to fix any site coordinates. Given n globally distributed sites, n baseline lengths and n geocentric radii form polyhedron with each site at vertex and with geocenter at intersection of all radii. Geodetic information derived from structure of polyhedron and its change with time. Approach applied to any global geodetic technique.

  2. Saved by Iridium? An Alternative to GPS

    Science.gov (United States)

    2012-05-17

    know this. The enemy presents itself at any time, at any place, in many shapes and forms, often for no apparent reason. As Ecclesiastes 9:18 states...These physical architectures correspond to ground operations in scenarios ranging from complete air superiority to completely denied airspace.”86 A...not interfere with today’s GPS architectures .88 The second developed alternative from Dr. Asher’s group is the Rapidly Deployable Satellite

  3. Absolute GPS Positioning Using Genetic Algorithms

    Science.gov (United States)

    Ramillien, G.

    A new inverse approach for restoring the absolute coordinates of a ground -based station from three or four observed GPS pseudo-ranges is proposed. This stochastic method is based on simulations of natural evolution named genetic algorithms (GA). These iterative procedures provide fairly good and robust estimates of the absolute positions in the Earth's geocentric reference system. For comparison/validation, GA results are compared to the ones obtained using the classical linearized least-square scheme for the determination of the XYZ location proposed by Bancroft (1985) which is strongly limited by the number of available observations (i.e. here, the number of input pseudo-ranges must be four). The r.m.s. accuracy of the non -linear cost function reached by this latter method is typically ~10-4 m2 corresponding to ~300-500-m accuracies for each geocentric coordinate. However, GA can provide more acceptable solutions (r.m.s. errors < 10-5 m2), even when only three instantaneous pseudo-ranges are used, such as a lost of lock during a GPS survey. Tuned GA parameters used in different simulations are N=1000 starting individuals, as well as Pc=60-70% and Pm=30-40% for the crossover probability and mutation rate, respectively. Statistical tests on the ability of GA to recover acceptable coordinates in presence of important levels of noise are made simulating nearly 3000 random samples of erroneous pseudo-ranges. Here, two main sources of measurement errors are considered in the inversion: (1) typical satellite-clock errors and/or 300-metre variance atmospheric delays, and (2) Geometrical Dilution of Precision (GDOP) due to the particular GPS satellite configuration at the time of acquisition. Extracting valuable information and even from low-quality starting range observations, GA offer an interesting alternative for high -precision GPS positioning.

  4. Arctic tides from GPS on sea ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing o......-gauges and altimetry data. Furthermore, we prove that the geodetic reference ellipsoid WGS84, can be interpolated to the tidal defined zero level by applying geophysical corrections to the GPS data....

  5. Using GPS to Detect Imminent Tsunamis

    Science.gov (United States)

    Song, Y. Tony

    2009-01-01

    A promising method of detecting imminent tsunamis and estimating their destructive potential involves the use of Global Positioning System (GPS) data in addition to seismic data. Application of the method is expected to increase the reliability of global tsunami-warning systems, making it possible to save lives while reducing the incidence of false alarms. Tsunamis kill people every year. The 2004 Indian Ocean tsunami killed about 230,000 people. The magnitude of an earthquake is not always a reliable indication of the destructive potential of a tsunami. The 2004 Indian Ocean quake generated a huge tsunami, while the 2005 Nias (Indonesia) quake did not, even though both were initially estimated to be of the similar magnitude. Between 2005 and 2007, five false tsunami alarms were issued worldwide. Such alarms result in negative societal and economic effects. GPS stations can detect ground motions of earthquakes in real time, as frequently as every few seconds. In the present method, the epicenter of an earthquake is located by use of data from seismometers, then data from coastal GPS stations near the epicenter are used to infer sea-floor displacements that precede a tsunami. The displacement data are used in conjunction with local topographical data and an advanced theory to quantify the destructive potential of a tsunami on a new tsunami scale, based on the GPS-derived tsunami energy, much like the Richter Scale used for earthquakes. An important element of the derivation of the advanced theory was recognition that horizontal sea-floor motions contribute much more to generation of tsunamis than previously believed. The method produces a reliable estimate of the destructive potential of a tsunami within minutes typically, well before the tsunami reaches coastal areas. The viability of the method was demonstrated in computational tests in which the method yielded accurate representations of three historical tsunamis for which well-documented ground

  6. Azimuth selection for sea level measurements using geodetic GPS receivers

    Science.gov (United States)

    Wang, Xiaolei; Zhang, Qin; Zhang, Shuangcheng

    2018-03-01

    Based on analysis of Global Positioning System (GPS) multipath signals recorded by a geodetic GPS receiver, GPS Reflectometry (GPS-R) has demonstrated unique advantages in relation to sea level monitoring. Founded on multipath reflectometry theory, sea level changes can be measured by GPS-R through spectral analysis of recorded signal-to-noise ratio data. However, prior to estimating multipath parameters, it is necessary to define azimuth and elevation angle mask to ensure the reflecting zones are on water. Here, a method is presented to address azimuth selection, a topic currently under active development in the field of GPS-R. Data from three test sites: the Kachemak Bay GPS site PBAY in Alaska (USA), Friday Harbor GPS site SC02 in the San Juan Islands (USA), and Brest Harbor GPS site BRST in Brest (France) are analyzed. These sites are located in different multipath environments, from a rural coastal area to a busy harbor, and they experience different tidal ranges. Estimates by the GPS tide gauges at azimuths selected by the presented method are compared with measurements from physical tide gauges and acceptable correspondence found for all three sites.

  7. GPS Water Vapor Tomography Based on Accurate Estimations of the GPS Tropospheric Parameters

    Science.gov (United States)

    Champollion, C.; Masson, F.; Bock, O.; Bouin, M.; Walpersdorf, A.; Doerflinger, E.; van Baelen, J.; Brenot, H.

    2003-12-01

    The Global Positioning System (GPS) is now a common technique for the retrieval of zenithal integrated water vapor (IWV). Further applications in meteorology need also slant integrated water vapor (SIWV) which allow to precisely define the high variability of tropospheric water vapor at different temporal and spatial scales. Only precise estimations of IWV and horizontal gradients allow the estimation of accurate SIWV. We present studies developed to improve the estimation of tropospheric water vapor from GPS data. Results are obtained from several field experiments (MAP, ESCOMPTE, OHM-CV, IHOP, .). First IWV are estimated using different GPS processing strategies and results are compared to radiosondes. The role of the reference frame and the a priori constraints on the coordinates of the fiducial and local stations is generally underestimated. It seems to be of first order in the estimation of the IWV. Second we validate the estimated horizontal gradients comparing zenith delay gradients and single site gradients. IWV, gradients and post-fit residuals are used to construct slant integrated water delays. Validation of the SIWV is under progress comparing GPS SIWV, Lidar measurements and high resolution meteorological models (Meso-NH). A careful analysis of the post-fit residuals is needed to separate tropospheric signal from multipaths. The slant tropospheric delays are used to study the 3D heterogeneity of the troposphere. We develop a tomographic software to model the three-dimensional distribution of the tropospheric water vapor from GPS data. The software is applied to the ESCOMPTE field experiment, a dense network of 17 dual frequency GPS receivers operated in southern France. Three inversions have been successfully compared to three successive radiosonde launches. Good resolution is obtained up to heights of 3000 m.

  8. Simple Air Temperature Estimation Method from MODIS Satellite Images on a Regional Scale Método Simple de Estimación de Temperatura del Aire a Escala Regional, a Partir de Imágenes Satelitales MODIS

    Directory of Open Access Journals (Sweden)

    Fabiola Flores P

    2010-09-01

    Full Text Available Agricultural studies on a regional scale about water balance and evapotranspiration estimation, among others, require estimating air temperature (Ta spatial variation since the generally low density of weather stations does not allow obtaining such data for a specific area. The aim of this study was to estimate air temperature through atmospheric profiles provided by the Moderate Resolution Imaging Spectroradiometer (MODIS sensor on a regional level. One of the present-day methodologies estimates Ta through vertical temperature profiles, which is why modifications to this methodology were proposed for zoning, surface elevation, and pressure/altitude ratios. By applying this new methodology, better Ta estimates were obtained by replacing the MODIS sensor surface elevation with those of the Shuttle Radar Topography Mission (SRTM. Finally, it was possible to estimate Ta spatial variation only from remotely sensed data in various geomorphological areas.Para estudios relacionados con la agricultura a escala regional, como balance hídrico y estimación de evapotranspiración entre otros, es importante estimar la variación espacial de la temperatura del aire (Ta, ya que la baja densidad de estaciones meteorológicas no permite obtener dichos datos para una zona determinada. El objetivo de este trabajo fue estimar Ta a partir de perfiles atmosféricos proporcionados por el sensor de imágenes espectroradiométricas de resolución moderada (MODIS a nivel regional. Una de las metodologías actuales estima la Ta a partir de perfiles verticales de temperatura, por lo que se plantearon modificaciones a dicha metodología en la zonificación, superficie de elevación y relación presión-altitud. Al aplicar esta nueva metodología, las mejores estimaciones de Ta se consiguieron al reemplazar la superficie de elevación del sensor MODIS por la misión topográfica de plataforma radar (SRTM. Finalmente, fue posible estimar la variación espacial de Ta

  9. GPS Modeling and Analysis. Summary of Research: GPS Satellite Axial Ratio Predictions

    Science.gov (United States)

    Axelrad, Penina; Reeh, Lisa

    2002-01-01

    This report outlines the algorithms developed at the Colorado Center for Astrodynamics Research to model yaw and predict the axial ratio as measured from a ground station. The algorithms are implemented in a collection of Matlab functions and scripts that read certain user input, such as ground station coordinates, the UTC time, and the desired GPS (Global Positioning System) satellites, and compute the above-mentioned parameters. The position information for the GPS satellites is obtained from Yuma almanac files corresponding to the prescribed date. The results are displayed graphically through time histories and azimuth-elevation plots.

  10. Estudio del movimiento de estructuras dinámicas mediante el uso de GPS.

    Directory of Open Access Journals (Sweden)

    Juan G. Serpas

    2016-03-01

    Full Text Available En la escuela de Topografía, Catastro y Geodesia de la Universidad Nacional, se realizó una investigación sobre el uso del sistema de posicionamiento global por satélite (GPS para la determinación del movimiento dinámico sobre estructuras civiles. Estas estructuras son diseñadas de forma que tengan un cierto grado de elasticidad, lo que permite un permanente movimiento, evitando así la fractura de la estructura misma. La actividad de investigación tuvo como fin el desarrollo y análisis de procedimientos y metodologías para determinar es una forma eficiente, económica y sencilla el movimiento de las estructuras, tanto en períodos cortos como largos. En el estudio se aplicaron técnicas espectrales para el análisis de los datos brindados por receptores GPS colocados sobre el puente del río Tempisque, Costa Rica. El objetivo de dicho análisis es la determinación de la magnitud del movimiento sufrido por ese puente en periodos cortos y largos.

  11. Precise Orbit Determination of GPS Satellites Using Phase Observables

    Directory of Open Access Journals (Sweden)

    Myung-Kook Jee

    1997-12-01

    Full Text Available The accuracy of user position by GPS is heavily dependent upon the accuracy of satellite position which is usually transmitted to GPS users in radio signals. The real-time satellite position information directly obtained from broadcast ephimerides has the accuracy of 3 x 10 meters which is very unsatisfactory to measure 100km baseline to the accuracy of less than a few mili-meters. There are globally at present seven orbit analysis centers capable of generating precise GPS ephimerides and their orbit quality is of the order of about 10cm. Therefore, precise orbit model and phase processing technique were reviewed and consequently precise GPS ephimerides were produced after processing the phase observables of 28 global GPS stations for 1 day. Initial 6 orbit parameters and 2 solar radiation coefficients were estimated using batch least square algorithm and the final results were compared with the orbit of IGS, the International GPS Service for Geodynamics.

  12. Continuing medical education and burnout among Danish GPs

    DEFF Research Database (Denmark)

    Brøndt, Anders; Sokolowski, Ineta; Olesen, Frede

    2008-01-01

    BACKGROUND: There has been minimal research into continuing medical education (CME) and its association with burnout among GPs. AIM: The aim of this study was to investigate the association between participating in CME and experiencing burnout in a sample of Danish GPs. DESIGN OF STUDY: Cross......-sectional questionnaire study. SETTING: All 458 active GPs in 2004, in the County of Aarhus, Denmark were invited to participate. METHOD: Data on CME activities were obtained for all GPs and linked to burnout which was measured using the Maslach Burnout Inventory - Human Services Survey. The relationship between CME...... activity and burnout was calculated as prevalence ratios (PR) in a generalised linear model. RESULTS: In total, 379 (83.5%) GPs returned the questionnaire. The prevalence of burnout was about 25%, and almost 3% suffered from 'high burnout'. A total of 344 (92.0%) GPs were members of a CME group...

  13. GPS operations at Olkiluoto, Kivetty and Romuvaara in 2010

    International Nuclear Information System (INIS)

    Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M.

    2011-11-01

    The Finnish Geodetic Institute (FGI) has studied crustal deformations in co-operation with the Posiva Oy since 1994, when a network of ten pillars for GPS observations was established at Olkiluoto. In 2010 the local GPS network at Olkiluoto consisted of 14 concrete pillars. The whole network has been measured twice a year in the static GPS campaigns with 24 h sessions. The four new pillars were established in 2010 and the permanent measurements on them will start in 2011. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. A total of 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 18 campaigns at Kivetty and Romuvaara. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured in connection to the GPS observations using the EDM instrument Kern ME5000 Mekometer. The GPS operations in 2010 included the two GPS campaigns at Olkiluoto, GPS campaigns at Kivetty and Romuvaara, EDM baseline measurements at Olkiluoto, and the control marker measurements with the tachymeter at Olkiluoto. All GPS data history was reprocessed with Bernese GPS software using the new processing strategy tested in 2009. The results were analysed by computing the change rates of the baselines and estimating horizontal velocities for the pillars using the barycenter of the velocities as a reference. In the Olkiluoto inner network 80 percent of the change rates were smaller than 0.10 mm/a. Roughly one fourth of the change rates could be considered as statistically significant (change rate larger than 3 σ. The statistically significant change rates were mainly related to the Olkiluoto permanent station (GPS1) and to the pillar GPS5, which had also the maximum change rate (0.21 ± 0.03 mm/a). In Olkiluoto outer network the maximum and statistically significant change rates are

  14. Penerapan Teknologi GPS Tracker Untuk Identifikasi Kondisi Traffik Jalan Raya

    Directory of Open Access Journals (Sweden)

    IM. O. Widyantara

    2015-06-01

    Full Text Available Real time tracking system technology has been made possible by integrating three technologies, namely global positioning system (GPS, database technologies such as geographic information system (GIS and mobile telecommunications technologies such as general packet radio service (GPRS. This paper has proposed a vehicle tracking mechanism based on GPS tracker to build a real-time traffic information system. A GPS server is built to process data of position and speed of the vehicle for further processed into vehicle traffic information. The Server and GPS tracker is designed to communicate using GPRS services in real time. Furthermore, the server processes the data from the GPS tracker into traffic information such as traffic jam, dense, medium and smoothly. Test results showed that the GPS server is able to visualize the real position of the vehicle and is able to decide the category of traffic information in real time.

  15. GPS operations at Olkiluoto, Kivetty and Romuvaara in 2010

    Energy Technology Data Exchange (ETDEWEB)

    Kallio, U.; Nyberg, S.; Koivula, H.; Jokela, J.; Poutanen, M. [Finnish Geodetic Institute, Masala (Finland)

    2011-11-15

    The Finnish Geodetic Institute (FGI) has studied crustal deformations in co-operation with the Posiva Oy since 1994, when a network of ten pillars for GPS observations was established at Olkiluoto. In 2010 the local GPS network at Olkiluoto consisted of 14 concrete pillars. The whole network has been measured twice a year in the static GPS campaigns with 24 h sessions. The four new pillars were established in 2010 and the permanent measurements on them will start in 2011. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. A total of 28 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 18 campaigns at Kivetty and Romuvaara. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured in connection to the GPS observations using the EDM instrument Kern ME5000 Mekometer. The GPS operations in 2010 included the two GPS campaigns at Olkiluoto, GPS campaigns at Kivetty and Romuvaara, EDM baseline measurements at Olkiluoto, and the control marker measurements with the tachymeter at Olkiluoto. All GPS data history was reprocessed with Bernese GPS software using the new processing strategy tested in 2009. The results were analysed by computing the change rates of the baselines and estimating horizontal velocities for the pillars using the barycenter of the velocities as a reference. In the Olkiluoto inner network 80 percent of the change rates were smaller than 0.10 mm/a. Roughly one fourth of the change rates could be considered as statistically significant (change rate larger than 3 {sigma}. The statistically significant change rates were mainly related to the Olkiluoto permanent station (GPS1) and to the pillar GPS5, which had also the maximum change rate (0.21 {+-} 0.03 mm/a). In Olkiluoto outer network the maximum and statistically significant change rates

  16. GeoTravel: Harvesting Ambient Geographic Footprints from GPS Trajectories

    OpenAIRE

    Liew, Li Ching; Goh, Ong Sing

    2014-01-01

    This study is about harvesting point of interest from GPS trajectories. Trajectories are the paths that moving objects move by follow through space in a function of time while GPS trajectories generally are point-sequences with geographic coordinates, time stamp, speed and heading. User can get information from GPS enable device. For example, user can acquire present location, search the information around them and design driving routes to a destination and thus design travel itineraries. By ...

  17. Briefing Highlights Vulnerability of GPS to Adverse Space Weather

    Science.gov (United States)

    Balcerak, Ernie

    2011-08-01

    Through its effects on GPS and other technologies, space weather can affect a variety of industries, including agriculture, commercial air travel, and emergency response. Speakers focused on these topics at a 22 June briefing on Capitol Hill in Washington, D. C. Solar flares can produce radio bursts that directly interfere with GPS signals. Solar activity can also cause ionospheric disturbances that produce distortions and delays in GPS signals, degrading the accuracy of positioning and navigation systems.

  18. Greenland ice mass balance from GPS, GRACE and ICESat

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Kjær, Kurt H.; Korsgaard, Niels Jákup

    Greenland, using stereoscopic coverage by aerial photographs recorded in 1985, and subsequent comparative surface elevation data from ICESat (Ice, Cloud and land Elevation Satellite) and ATM (Airborne Topographic Mapper) supplemented with measurements from GPS and the Gravity Recovery and Climate Experiment...... (GRACE) satellite gravity mission, launched in March, 2002. The GRACE results provide a direct measure of mass loss, while the GPS data are used to monitor crustal uplift caused by ice mass loss close to the GPS sites....

  19. Arctic tides from GPS on sea ice

    OpenAIRE

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    2012-01-01

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea ice dampens the ocean tide amplitude with the result that global tidal models which use only astronomical data perform less accurately in the polar regions. This study presents a kinematic processing of Global Positioning System (GPS) buoys placed on sea-ice at five different sites north of Greenland for the study of sea level height and tidal analysis to improve tidal models in the Central Arctic....

  20. Nuclear-Powered GPS Spacecraft Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Bernard

    1977-05-01

    This is the final report of a study to investigate the potential benefits of a nuclear (radioisotope) - powered satellite for advanced phases of the Global Positioning System (GPS) program. The critical parameters were: power to user; mean mission duration; orbital predictability; thermal control of on-board frequency standards; and vulnerability. The reference design approach is described, and input data are given for two power systems that are under development: an organic Rankine system and a Brayton cycle system. Reference design details are provided and structural design and analysis are discussed, as well as thermal design and analysis. A higher altitude version is also considered.

  1. GPS-Based AR Games Development Potential

    Directory of Open Access Journals (Sweden)

    Gregorius Alvin Raditya Santoso

    2014-11-01

    Full Text Available The application of new technologies in a game is not a new thing. One example is the application of Augmented Reality (AR technology in game. Many people do not know the application of AR technology in game, although the application of this technology is able to produce a game with unique gameplay. In addition, since AR game is GPS-based, it offers new gaming experience, that is, playing outdoors in which the real world becomes the game arena. This advantage gives the AR technology a huge potential to be developed into a game

  2. Topo-Iberia GPS network: installation complete

    Science.gov (United States)

    Khazaradze, G.

    2009-04-01

    As part of the project, titled "Geociencias en Iberia: Estudios integrados de topografía y evolución 4D: Topo-Iberia", we have established a network of 26 continuous GPS stations, covering the Spanish part of the Iberian Peninsula (22 stations) and Morocco (4 stations). A major objective behind the establishment of this array is to monitor millimeter level deformation of the crust due to the collision of African and Eurasian (including Iberian) tectonic plates. More specific goals of the project include the identification of the areas and/or specific seismic faults which exhibit higher deformation rates, which could imply an increased seismic hazard in these specific areas. The network has been designed as two X-shaped transects crossing the peninsula from NE to SW and NW to SE, with relatively coarse distribution of the stations, superimposed with denser coverage in the seismically active areas of the Betics, Pyrenees and Cantabrian chains. The majority of the built monuments consist of 1.5-1.8 m tall concrete pillars of 40 cm in diameter anchored to the bedrock using iron rebars. One station in Huesca was built according the UNAVCO's short drilled braced monument (SDBM) specifications. All the monuments were equipped with the SCIGN leveling mounts to ensure the precise antenna alignment and re-alignment in case of the antenna replacement, as well as, tamper resistance of the monument mark. In places were the snow accumulation was possible the antennas were covered with plastic radomes. The instrumentation used is Trimble NetRS dual-frequency receivers with choke-ring antennas. The communication is mainly via cellular telephone system. As of December 2008, the network installation has been competed and all the stations are fully operational. Here we report the milestones of the installation of the network and, as well as, present the first preliminary results of the analysis of the data. Besides the newly established Topo-Iberia CGPS stations, we have included

  3. GPS Operations at Olkiluoto, Kivetty and Romuvaara in 2005

    International Nuclear Information System (INIS)

    Ahola, J.; Ollikainen, M.; Koivula, H.; Jokela, J.

    2006-07-01

    The GPS based deformation studies has been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. Twenty GPS measurement campaigns have been carried out at Olkiluoto since 1995, and fourteen campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ± 0.22 mm/a. There are no statistically signicant movements at Kivetty and Romuvaara expect one pillar at Romuvaara. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. The local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliable (maximum velocity is - 0.25 mm/a ± 0.025 mm/a). The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments simultaneously with the GPS observations. The comparison between the GPS and EDM results to show a possible scale error of the GPS. The GPS network at Olkiluoto was enlarged in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari, both north from Olkiluoto. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed five times since 2003, but the time series are still too short for reliable deformation studies. Including the new pillars the local

  4. GPS operations at Olkiluoto, Kivetty and Romuvaara in 2006

    International Nuclear Information System (INIS)

    Ahola, J.; Koivula, H.; Poutanen, M.; Jokela, J.

    2007-05-01

    The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. 22 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 15 campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ± 0.22 mm/a. The networks of Kivetty and Romuvaara are quite stabile expect one pillar at Romuvaara. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined (maximum velocity is -0.23 mm/a ± 0.023 mm/a). The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments simultaneously with the GPS observations. The comparison between the GPS and EDM results can solve a possible scale error of the GPS. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003, but the time series are still too short for reliable deformation studies. The local crustal deformations have been studied in GeoSatakunta project, too. This

  5. Uporaba satelitskih sistemov GPS in GLONASS v geodetski izmeri

    OpenAIRE

    Oset, Klemen

    2015-01-01

    V geodetski izmeri GNSS se že nekaj časa za določanje položaja uporabljata hkrati sistema GLONASS in GPS. V diplomski nalogi sta predstavljena GNSS sistema GPS in GLONASS, podobnosti in razlike obeh sistemov ter njune značilnosti pri določitvi položaja. V praktičnem delu naloge so predstavljeni potek meritev, obdelava opazovanj in analiza kakovosti koordinat določenih na osnovi opazovanj GPS, opazovanj GLONASS in skupne uporabe opazovanj GPS in GLONASS.

  6. GPS-based system for satellite tracking and geodesy

    Science.gov (United States)

    Bertiger, Willy I.; Thornton, Catherine L.

    1989-01-01

    High-performance receivers and data processing systems developed for GPS are reviewed. The GPS Inferred Positioning System (GIPSY) and the Orbiter Analysis and Simulation Software (OASIS) are described. The OASIS software is used to assess GPS system performance using GIPSY for data processing. Consideration is given to parameter estimation for multiday arcs, orbit repeatability, orbit prediction, daily baseline repeatability, agreement with VLBI, and ambiguity resolution. Also, the dual-frequency Rogue receiver, which can track up to eight GPS satellites simultaneously, is discussed.

  7. GPS Receivers Use-Case Information : GPS Adjacent Band Compatibility Assessment Workshop

    Science.gov (United States)

    2014-09-18

    Topics 1. Background. 2. Use Case Template. 3. Description of Submitted UseCases from DOT Extended Pos/Nav Working Group. 4. Utilization of UseCase Information. 5. Request of Information for Additional UseCases from GPS Receiver Manufacturer...

  8. GPS on Every Roof, GPS Sensor Network for Post-Seismic Building-Wise Damage Identification

    Directory of Open Access Journals (Sweden)

    Kenji Oguni

    2013-12-01

    Full Text Available Development of wireless sensor network equipped with GPS for post-seismic building-wise damage identification is presented in this paper. This system is called GPS on Every Roof. Sensor node equipped with GPS antenna and receiver is installed on the top of the roof of each and every building. The position of this sensor node is measured before and after earthquake. The final goal of this system is to i identify the displacement of the roof of each house and ii collect the information of displacement of the roof of the houses through wireless communication. Superposing this information on GIS, building-wise damage distribution due to earthquake can be obtained. The system overview, hardware and some of the key components of the system such as on-board GPS relative positioning algorithm to achieve the accuracy in the order of several centimeters are described in detail. Also, the results from a field experiment using a wireless sensor network with 39 sensor nodes are presented.

  9. Ionospheric error analysis in gps measurements

    Directory of Open Access Journals (Sweden)

    G. Pugliano

    2008-06-01

    Full Text Available The results of an experiment aimed at evaluating the effects of the ionosphere on GPS positioning applications are presented in this paper. Specifically, the study, based upon a differential approach, was conducted utilizing GPS measurements acquired by various receivers located at increasing inter-distances. The experimental research was developed upon the basis of two groups of baselines: the first group is comprised of "short" baselines (less than 10 km; the second group is characterized by greater distances (up to 90 km. The obtained results were compared either upon the basis of the geometric characteristics, for six different baseline lengths, using 24 hours of data, or upon temporal variations, by examining two periods of varying intensity in ionospheric activity respectively coinciding with the maximum of the 23 solar cycle and in conditions of low ionospheric activity. The analysis revealed variations in terms of inter-distance as well as different performances primarily owing to temporal modifications in the state of the ionosphere.

  10. TAGGING, TRACKING AND LOCATING WITHOUT GPS

    Energy Technology Data Exchange (ETDEWEB)

    Cordaro, J.; Coleman, T.; Shull, D.

    2012-07-08

    The Savannah River National Laboratory (SRNL) was requested to lead a Law Enforcement Working Group that was formed to collaborate on common operational needs. All agencies represented on the working group ranked their need to tag, track, and locate a witting or unwitting target as their highest priority. Specifically, they were looking for technologies more robust than Global Positioning Satellite (GPS), could communicate back to the owner, and worked where normal cell phone communications did not work or were unreliable. SRNL brought together multiple technologies in a demonstration that was held in in various Alaska venues, including metropolitan, wilderness, and at-sea that met the working group's requirements. Using prototypical technologies from Boeing, On Ramp, and Fortress, SRNL was able to demonstrate the ability to track personnel and material in all scenarios including indoors, in heavily wooden areas, canyons, and in parking garages. In all cases GPS signals were too weak to measure. Bi-directional communication was achieved in areas that Wi-Fi, cell towers, or traditional radios would not perform. The results of the exercise will be presented. These technologies are considered ideal for tracking high value material such has nuclear material with a platform that allows seamless tracking anywhere in the world, indoors or outdoors.

  11. Self reported involvement in emergency medicine among GPs in Norway.

    Science.gov (United States)

    Hjortdahl, Magnus; Zakariassen, Erik; Halvorsen, Peder A

    2018-04-10

    To examine general practitioners' (GPs') perception of their role in emergency medicine and participation in emergency services including ambulance call outs, and the characteristics of the GPs and casualty clinics associated with the GPs' involvement in emergency medicine. Cross-sectional online survey. General practice. General practitioners in Norway (n = 1002). Proportion of GPs perceiving that they have a large role in emergency medicine, regularly being on call, and the proportion of ambulance callouts with GP participation. Forty six percent of the GPs indicated that they play a large role in emergency medicine, 63 percent of the GPs were regularly on call, and 28 percent responded that they usually took part in ambulance call outs. Multivariable logistic regression analyses indicated that these outcomes were strongly associated with participation in multidisciplinary training. Furthermore, the main outcomes were associated with traits commonly seen at smaller casualty clinics such as those with an absence of nursing personnel and extra physicians, and based on the distance to the hospital. Our findings suggest that GPs play an important role in emergency medicine. Multidisciplinary team training may be important for their continued involvement in prehospital emergencies. Key Points   Health authorities and other stakeholders have raised concerns about general practitioner's (GPs) participation in emergency medicine, but few have studied opinions and perceptions among the GPs themselves.   • Norwegian GPs report playing a large role in emergency medicine, regularly being on call, and taking part in selected ambulance call outs.   • A higher proportion of GPs who took part in team training perceived themselves as playing a large role in emergency medicine, regularly being on call, and taking part in ambulance call outs.   • These outcomes were also associated with attributes commonly seen at smaller casualty clinics.

  12. Outcome prediction in gastroschisis - The gastroschisis prognostic score (GPS) revisited.

    Science.gov (United States)

    Puligandla, Pramod S; Baird, Robert; Skarsgard, Eric D; Emil, Sherif; Laberge, Jean-Martin

    2017-05-01

    The GPS enables risk stratification for gastroschisis and helps discriminate low from high morbidity groups. The purpose of this study was to revalidate GPS's characterization of a high morbidity group and to quantify relationships between the GPS and outcomes. With REB approval, complete survivor data from a national gastroschisis registry was collected. GPS bowel injury scoring was revalidated excluding the initial inception/validation cohorts (>2011). Length of stay (LOS), 1st enteral feed days (dFPO), TPN days (dTPN), and aggregate complications (COMP) were compared between low and high morbidity risk groups. Mathematical relationships between outcomes and integer increases in GPS were explored using the entire cohort (2005-present). Median (range) LOS, dPO, and dTPN for the entire cohort (n=849) was 36 (26,62), 13 (9,18), and 27 (20,46) days, respectively. High-risk patients (GPS≥2; n=80) experienced significantly worse outcomes than low risk patients (n=263). Each integer increase in GPS was associated with increases in LOS and dTPN by 16.9 and 12.7days, respectively (pGPS effectively discriminates low from high morbidity risk groups. Within the high risk group, integer increases in GPS produce quantitatively differentiated outcomes which may guide initial counseling and resource allocation. IIb. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Ionospheric correction for spaceborne single-frequency GPS based ...

    Indian Academy of Sciences (India)

    A modified ionospheric correction method and the corresponding approximate algorithm for spaceborne single-frequency Global Positioning System (GPS) users are proposed in this study. Single Layer Model (SLM) mapping function for spaceborne GPS was analyzed. SLM mapping functions at different altitudes were ...

  14. Horses for Courses: Designing a GPS Tracking Data Collection

    DEFF Research Database (Denmark)

    Reinau, Kristian Hegner; Harder, Henrik; Overgård, Christian Hansen

    2014-01-01

    and practical experiences from a number of GPS tracking projects into a practical guideline. Researchers can use this model as a starting point when designing a GPS tracking data collection. The authors hope that the model can constitute a first step towards the development of best practice....

  15. 78 FR 67132 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-11-08

    ... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Control Working Group... simulator manufacturers, who supply products to the Department of Defense (DoD), and GPS simulator users..., and email address) to [email protected]us.af.mil and have your security personnel submit your VAR...

  16. Two laboratory methods for the calibration of GPS speed meters

    International Nuclear Information System (INIS)

    Bai, Yin; Sun, Qiao; Du, Lei; Yu, Mei; Bai, Jie

    2015-01-01

    The set-ups of two calibration systems are presented to investigate calibration methods of GPS speed meters. The GPS speed meter calibrated is a special type of high accuracy speed meter for vehicles which uses Doppler demodulation of GPS signals to calculate the measured speed of a moving target. Three experiments are performed: including simulated calibration, field-test signal replay calibration, and in-field test comparison with an optical speed meter. The experiments are conducted at specific speeds in the range of 40–180 km h −1 with the same GPS speed meter as the device under calibration. The evaluation of measurement results validates both methods for calibrating GPS speed meters. The relative deviations between the measurement results of the GPS-based high accuracy speed meter and those of the optical speed meter are analyzed, and the equivalent uncertainty of the comparison is evaluated. The comparison results justify the utilization of GPS speed meters as reference equipment if no fewer than seven satellites are available. This study contributes to the widespread use of GPS-based high accuracy speed meters as legal reference equipment in traffic speed metrology. (paper)

  17. Advancing Technology: GPS and GIS Outreach Training for Agricultural Producers

    Science.gov (United States)

    Flynn, Allison; Arnold, Shannon

    2010-01-01

    The use of the Global Positioning System (GPS) and Global Information Systems (GIS) has made significant impacts on agricultural production practices. However, constant changes in the technologies require continuing educational updates. The outreach program described here introduces the operation, use, and applications of GPS receivers and GIS…

  18. Crustal deformations at permanent GPS sites in Denmark

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Knudsen, Per; Tscherning, Carl Christian

    2005-01-01

    The National Survey and Cadastre (KMS) is responsible for the geodetic definition of the reference network in Denmark. Permanent GPS stations play an important role in the monitoring and maintenance of the geodetic network. During 1998 and 1999 KMS established three permanent GPS station in Denma...

  19. GPS Usage in a Population of Low-Vision Drivers.

    Science.gov (United States)

    Cucuras, Maria; Chun, Robert; Lee, Patrick; Jay, Walter M; Pusateri, Gregg

    2017-01-01

    We surveyed bioptic and non-bioptic low-vision drivers in Illinois, USA, to determine their usage of global positioning system (GPS) devices. Low-vision patients completed an IRB-approved phone survey regarding driving demographics and usage of GPS while driving. Participants were required to be active drivers with an Illinois driver's license, and met one of the following criteria: best-corrected visual acuity (BCVA) less than or equal to 20/40, central or significant peripheral visual field defects, or a combination of both. Of 27 low-vision drivers, 10 (37%) used GPS while driving. The average age for GPS users was 54.3 and for non-users was 77.6. All 10 drivers who used GPS while driving reported increased comfort or safety level. Since non-GPS users were significantly older than GPS users, it is likely that older participants would benefit from GPS technology training from their low-vision eye care professionals.

  20. PDOP values for simulated GPS/Galileo positioning

    DEFF Research Database (Denmark)

    Cederholm, Jens Peter

    2005-01-01

    The paper illustrates satellite coverage and PDOP values for a simulated combined GPS/Galileo system. The designed GPS satellite constellation and the planned Galileo satellite constellation are presented. The combined system is simulated and the number of visible satellites and PDOP values...

  1. Hiking and biking with GPS: The Canadian perspective

    Science.gov (United States)

    Vaníček, Petr

    The paper attempts to review and put into perspective the findings of a recent by-invitation-only workshop on GPS held in Ottawa. The workshop brought together both GPS-information suppliers and consumers coming from all walks of life. Some unique exchanges of views took place which are worth bringing to the attention of the geodetic community.

  2. Effect of forest canopy on GPS-based movement data

    Science.gov (United States)

    Nicholas J. DeCesare; John R. Squires; Jay A. Kolbe

    2005-01-01

    The advancing role of Global Positioning System (GPS) technology in ecology has made studies of animal movement possible for larger and more vagile species. A simple field test revealed that lengths of GPS-based movement data were strongly biased (Pof forest canopy. Global Positioning System error added an average of 27.5% additional...

  3. Stochastic Analysis of Differential GPS Surveys for Earth Dam ...

    African Journals Online (AJOL)

    In GPS measurement, we try to model not just the deterministic part of the measurement but also try to account for their stochastic behavior using the measurement variance-covariance matrix. The variance-covariance matrices are computed as part of a least squares adjustment. In this study, the results of GPS survey by ...

  4. Backyard Botany: Using GPS Technology in the Science Classroom

    Science.gov (United States)

    March, Kathryn A.

    2012-01-01

    Global Positioning System (GPS) technology can be used to connect students to the natural world and improve their skills in observation, identification, and classification. Using GPS devices in the classroom increases student interest in science, encourages team-building skills, and improves biology content knowledge. Additionally, it helps…

  5. Rip current monitoring using GPS buoy system

    Science.gov (United States)

    Song, DongSeob; Kim, InHo; Kang, DongSoo

    2014-05-01

    The occurrence of rip current in the Haeundae beach, which is one of the most famous beaches in South Korea, has been threatening beach-goers security in summer season annually. Many coastal scientists have been investigating rip currents by using field observations and measurements, laboratory measurements and wave tank experiments, and computer and numerical modeling. Rip current velocity is intermittent and may rapidly increase within minutes due to larger incoming wave groups or nearshore circulation instabilities. It is important to understand that changes in rip current velocity occur in response to changes in incoming wave height and period as well as changes in water level. GPS buoys have been used to acquire sea level change data, atmospheric parameters and other oceanic variables in sea for the purposes of vertical datum determination, tide correction, radar altimeter calibration, ocean environment and marine pollution monitoring. Therefore, we adopted GPS buoy system for an experiment which is to investigate rip current velocity; it is sporadic and may quickly upsurge within minutes due to larger arriving wave groups or nearshore flow uncertainties. In this study, for high accurate positioning of buy equipment, a Satellite Based Argumentation System DGPS data logger was deployed to investigate within floating object, and it can be acquired three-dimensional coordinate or geodetic position of buoy with continuous NMEA-0183 protocol during 24 hours. The wave height measured by in-situ hydrometer in a cross-shore array clearly increased before and after occurrence of rip current, and wave period also was lengthened around an event. These results show that wave height and period correlate reasonably well with long-shore current interaction in the Haeundae beach. Additionally, current meter data and GPS buoy data showed that rip current velocities, about 0.2 m/s, may become dangerously strong under specific conditions. Acknowledgement This research was

  6. How and Why to Do VLBI on GPS

    Science.gov (United States)

    Dickey, J. M.

    2010-01-01

    In order to establish the position of the center of mass of the Earth in the International Celestial Reference Frame, observations of the Global Positioning Satellite (GPS) constellation using the IVS network are important. With a good frame-tie between the coordinates of the IVS telescopes and nearby GPS receivers, plus a common local oscillator reference signal, it should be possible to observe and record simultaneously signals from the astrometric calibration sources and the GPS satellites. The standard IVS solution would give the atmospheric delay and clock offsets to use in analysis of the GPS data. Correlation of the GPS signals would then give accurate orbital parameters of the satellites in the ICRF reference frame, i.e., relative to the positions of the astrometric sources. This is particularly needed to determine motion of the center of mass of the earth along the rotation axis.

  7. Estimering af brændstofforbrug vha. GPS Data

    DEFF Research Database (Denmark)

    Andersen, Ove; Lahrmann, Harry; Torp, Kristian

    2010-01-01

    Det er simpelt og billigt at opsamle GPS målinger fra køretøjer. Når større mængder GPS data indsamles fra et passende antal køretøjer kan dataen bruges til at beregne f.eks. køretider. Det er ligeledes muligt ud fra GPS data at estimere miljøindikatorer så som, hvor aggressivt kører bilister og er...... der nogle vejstrækninger, der har en højere (negativ) miljø påvirkning end andre? I denne artikel præsenterer et forsøg, hvor GPS data anvendes til at estimere brændstofforbruget ved en enkelt tur og for vejnettet generelt. Dette gøres ved at opbygge en database med GPS data. Ud fra disse data gives...

  8. Radiotracking large wilderness mammals: Integration of GPS and Argos technology

    Science.gov (United States)

    Schwartz, Charles C.; Arthur, Steve M.

    1999-01-01

    We tested 30 prototype global positioning system (GPS) radiocollars on brown bears (Ursus arctos) over a 3-year period on the Kenai Peninsula, Alaska. Collars were of 2 design types: GPS with an Argos (Argos Data collection and Location System) satellite uplink (n=19) and GPS unites where the data were stored on board (n=10) for retrieval at a later date. All units also contained a conventional VHF (very high frequency) transmitter and weighed 1.7 kg. GPS-Argos united obtained 10-82% of expected GPS fixes, and fix rate declined significantly (Pbears varied more and were lower than fix rates for stationary collars placed in various vegetation types, suggesting that the bear, terrain, and movement all influence both fix and uplink success rate. Application of this new technology to grizzly and brown bear research and comparisons to studies with moose (Alces alces) are discussed.

  9. Localization system for use in GPS denied environments

    Energy Technology Data Exchange (ETDEWEB)

    Trueblood, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-02-01

    The military uses to autonomous platforms to complete missions to provide standoff for the warfighters. However autonomous platforms rely on GPS to provide their global position. In many missions spaces the autonomous platforms may encounter GPS denied environments which limits where the platform operates and requires the warfighters to takes its place. GPS denied environments can occur due to tall building, trees, canyon wall blocking the GPS satellite signals or a lack of coverage. An Inertial Navigation System (INS) uses sensors to detect the vehicle movement and direction its traveling to calculate the vehicle. One of biggest challenges with an INS system is the accuracy and accumulation of errors over time of the sensors. If these challenges can be overcome the INS would provide accurate positioning information to the autonomous vehicle in GPS denied environments and allow them to provide the desired standoff for the warfighters.

  10. Devices using GPS into driving simulators

    OpenAIRE

    ESPIE, S; GANIEUX, D; TOURNIER, N

    2004-01-01

    Cet article présente un nouvel outil utilisant des données SIG pour obtenir une définition analytique des routes afin que la base de données réponde aux besoins des simulateurs de conduite (modèle dynamique du véhicule, simulation de trafic, module sonore, etc.). Le simulateur peut calculer en temps réel les informations GPS simulées (SIL) et les envoyer au calculateur (HIS) qui fonctionne alors comme s'il équipait un véhicule réel sur une vraie route, dans des conditions réelles.

  11. GPS Software Packages Deliver Positioning Solutions

    Science.gov (United States)

    2010-01-01

    "To determine a spacecraft s position, the Jet Propulsion Laboratory (JPL) developed an innovative software program called the GPS (global positioning system)-Inferred Positioning System and Orbit Analysis Simulation Software, abbreviated as GIPSY-OASIS, and also developed Real-Time GIPSY (RTG) for certain time-critical applications. First featured in Spinoff 1999, JPL has released hundreds of licenses for GIPSY and RTG, including to Longmont, Colorado-based DigitalGlobe. Using the technology, DigitalGlobe produces satellite imagery with highly precise latitude and longitude coordinates and then supplies it for uses within defense and intelligence, civil agencies, mapping and analysis, environmental monitoring, oil and gas exploration, infrastructure management, Internet portals, and navigation technology."

  12. CASA Uno GPS orbit and baseline experiments

    Science.gov (United States)

    Schutz, B. E.; Ho, C. S.; Abusali, P. A. M.; Tapley, B. D.

    1990-01-01

    CASA Uno data from sites distributed in longitude from Australia to Europe have been used to determine orbits of the GPS satellites. The characteristics of the orbits determined from double difference phase have been evaluated through comparisons of two-week solutions with one-week solutions and by comparisons of predicted and estimated orbits. Evidence of unmodeled effects is demonstrated, particularly associated with the orbit planes that experience solar eclipse. The orbit accuracy has been assessed through the repeatability of unconstrained estimated baseline vectors ranging from 245 km to 5400 km. Both the baseline repeatability and the comparison with independent space geodetic methods give results at the level of 1-2 parts in 100,000,000. In addition, the Mojave/Owens Valley (245 km) and Kokee Park/Ft. Davis (5409 km) estimates agree with VLBI and SLR to better than 1 part in 100,000,000.

  13. Multiscale GPS tomography during COPS: validation and applications

    Science.gov (United States)

    Champollion, Cédric; Flamant, Cyrille; Masson, Frédéric; Gégout, Pascal; Boniface, Karen; Richard, Evelyne

    2010-05-01

    Accurate 3D description of the water vapour field is of interest for process studies such as convection initiation. None of the current techniques (LIDAR, satellite, radio soundings, GPS) can provide an all weather continuous 3D field of moisture. The combination of GPS tomography with radio-soundings (and/or LIDAR) has been used for such process studies using both advantages of vertically resolved soundings and high temporal density of GPS measurements. GPS tomography has been used at short scale (10 km horizontal resolution but in a 50 km² area) for process studies such as the ESCOMPTE experiment (Bastin et al., 2005) and at larger scale (50 km horizontal resolution) during IHOP_2002. But no extensive statistical validation has been done so far. The overarching goal of the COPS field experiment is to advance the quality of forecasts of orographically induced convective precipitation by four-dimensional observations and modeling of its life cycle for identifying the physical and chemical processes responsible for deficiencies in QPF over low-mountain regions. During the COPS field experiment, a GPS network of about 100 GPS stations has been continuously operating during three months in an area of 500 km² in the East of France (Vosges Mountains) and West of Germany (Black Forest). If the mean spacing between the GPS is about 50 km, an East-West GPS profile with a density of about 10 km is dedicated to high resolution tomography. One major goal of the GPS COPS experiment is to validate the GPS tomography with different spatial resolutions. Validation is based on additional radio-soundings and airborne / ground-based LIDAR measurement. The number and the high quality of vertically resolved water vapor observations give an unique data set for GPS tomography validation. Numerous tests have been done on real data to show the type water vapor structures that can be imaging by GPS tomography depending of the assimilation of additional data (radio soundings), the

  14. The Performance Analysis of a Real-Time Integrated INS/GPS Vehicle Navigation System with Abnormal GPS Measurement Elimination

    Directory of Open Access Journals (Sweden)

    Jhen-Kai Liao

    2013-08-01

    Full Text Available The integration of an Inertial Navigation System (INS and the Global Positioning System (GPS is common in mobile mapping and navigation applications to seamlessly determine the position, velocity, and orientation of the mobile platform. In most INS/GPS integrated architectures, the GPS is considered to be an accurate reference with which to correct for the systematic errors of the inertial sensors, which are composed of biases, scale factors and drift. However, the GPS receiver may produce abnormal pseudo-range errors mainly caused by ionospheric delay, tropospheric delay and the multipath effect. These errors degrade the overall position accuracy of an integrated system that uses conventional INS/GPS integration strategies such as loosely coupled (LC and tightly coupled (TC schemes. Conventional tightly coupled INS/GPS integration schemes apply the Klobuchar model and the Hopfield model to reduce pseudo-range delays caused by ionospheric delay and tropospheric delay, respectively, but do not address the multipath problem. However, the multipath effect (from reflected GPS signals affects the position error far more significantly in a consumer-grade GPS receiver than in an expensive, geodetic-grade GPS receiver. To avoid this problem, a new integrated INS/GPS architecture is proposed. The proposed method is described and applied in a real-time integrated system with two integration strategies, namely, loosely coupled and tightly coupled schemes, respectively. To verify the effectiveness of the proposed method, field tests with various scenarios are conducted and the results are compared with a reliable reference system.

  15. Performance of GPS-devices for environmental exposure assessment.

    Science.gov (United States)

    Beekhuizen, Johan; Kromhout, Hans; Huss, Anke; Vermeulen, Roel

    2013-01-01

    Integration of individual time-location patterns with spatially resolved exposure maps enables a more accurate estimation of personal exposures to environmental pollutants than using estimates at fixed locations. Current global positioning system (GPS) devices can be used to track an individual's location. However, information on GPS-performance in environmental exposure assessment is largely missing. We therefore performed two studies. First, a commute-study, where the commute of 12 individuals was tracked twice, testing GPS-performance for five transport modes and two wearing modes. Second, an urban-tracking study, where one individual was tracked repeatedly through different areas, focused on the effect of building obstruction on GPS-performance. The median error from the true path for walking was 3.7 m, biking 2.9 m, train 4.8 m, bus 4.9 m, and car 3.3 m. Errors were larger in a high-rise commercial area (median error=7.1 m) compared with a low-rise residential area (median error=2.2 m). Thus, GPS-performance largely depends on the transport mode and urban built-up. Although ~85% of all errors were 50 m. Modern GPS-devices are useful tools for environmental exposure assessment, but large GPS-errors might affect estimates of exposures with high spatial variability.

  16. Why GPS makes distances bigger than they are.

    Science.gov (United States)

    Ranacher, Peter; Brunauer, Richard; Trutschnig, Wolfgang; Van der Spek, Stefan; Reich, Siegfried

    2016-02-01

    Global navigation satellite systems such as the Global Positioning System (GPS) is one of the most important sensors for movement analysis. GPS is widely used to record the trajectories of vehicles, animals and human beings. However, all GPS movement data are affected by both measurement and interpolation errors. In this article we show that measurement error causes a systematic bias in distances recorded with a GPS; the distance between two points recorded with a GPS is - on average - bigger than the true distance between these points. This systematic 'overestimation of distance' becomes relevant if the influence of interpolation error can be neglected, which in practice is the case for movement sampled at high frequencies. We provide a mathematical explanation of this phenomenon and illustrate that it functionally depends on the autocorrelation of GPS measurement error ( C ). We argue that C can be interpreted as a quality measure for movement data recorded with a GPS. If there is a strong autocorrelation between any two consecutive position estimates, they have very similar error. This error cancels out when average speed, distance or direction is calculated along the trajectory. Based on our theoretical findings we introduce a novel approach to determine C in real-world GPS movement data sampled at high frequencies. We apply our approach to pedestrian trajectories and car trajectories. We found that the measurement error in the data was strongly spatially and temporally autocorrelated and give a quality estimate of the data. Most importantly, our findings are not limited to GPS alone. The systematic bias and its implications are bound to occur in any movement data collected with absolute positioning if interpolation error can be neglected.

  17. Assessing the role of GPs in Nordic health care systems.

    Science.gov (United States)

    Quaye, Randolph K

    2016-05-03

    Purpose This paper examines the changing role of general practitioners (GPs) in Nordic countries of Sweden, Norway and Denmark. It aims to explore the "gate keeping" role of GPs in the face of current changes in the health care delivery systems in these countries. Design/methodology/approach Data were collected from existing literature, interviews with GPs, hospital specialists and representatives of Danish regions and Norwegian Medical Association. Findings The paper contends that in all these changes, the position of the GPs in the medical division of labor has been strengthened, and patients now have increased and broadened access to choice. Research limitations/implications Health care cost and high cancer mortality rates have forced Nordic countries of Sweden, Norway and Denmark to rethink their health care systems. Several attempts have been made to reduce health care cost through market reform and by strenghtening the position of GPs. The evidence suggests that in Norway and Denmark, right incentives are in place to achieve this goal. Sweden is not far behind. The paper has limitations of a small sample size and an exclusive focus on GPs. Practical implications Anecdotal evidence suggests that physicians are becoming extremely unhappy. Understanding the changing status of primary care physicians will yield valuable information for assessing the effectiveness of Nordic health care delivery systems. Social implications This study has wider implications of how GPs see their role as potential gatekeepers in the Nordic health care systems. The role of GPs is changing as a result of recent health care reforms. Originality/value This paper contends that in Norway and Denmark, right incentives are in place to strengthen the position of GPs.

  18. Accuracy assessment of high-rate GPS measurements for seismology

    Science.gov (United States)

    Elosegui, P.; Davis, J. L.; Ekström, G.

    2007-12-01

    Analysis of GPS measurements with a controlled laboratory system, built to simulate the ground motions caused by tectonic earthquakes and other transient geophysical signals such as glacial earthquakes, enables us to assess the technique of high-rate GPS. The root-mean-square (rms) position error of this system when undergoing realistic simulated seismic motions is 0.05~mm, with maximum position errors of 0.1~mm, thus providing "ground truth" GPS displacements. We have acquired an extensive set of high-rate GPS measurements while inducing seismic motions on a GPS antenna mounted on this system with a temporal spectrum similar to real seismic events. We found that, for a particular 15-min-long test event, the rms error of the 1-Hz GPS position estimates was 2.5~mm, with maximum position errors of 10~mm, and the error spectrum of the GPS estimates was approximately flicker noise. These results may however represent a best-case scenario since they were obtained over a short (~10~m) baseline, thereby greatly mitigating baseline-dependent errors, and when the number and distribution of satellites on the sky was good. For example, we have determined that the rms error can increase by a factor of 2--3 as the GPS constellation changes throughout the day, with an average value of 3.5~mm for eight identical, hourly-spaced, consecutive test events. The rms error also increases with increasing baseline, as one would expect, with an average rms error for a ~1400~km baseline of 9~mm. We will present an assessment of the accuracy of high-rate GPS based on these measurements, discuss the implications of this study for seismology, and describe new applications in glaciology.

  19. Arctic Tides from GPS on sea-ice

    DEFF Research Database (Denmark)

    Kildegaard Rose, Stine; Skourup, Henriette; Forsberg, René

    2013-01-01

    The presence of sea-ice in the Arctic Ocean plays a significant role in the Arctic climate. Sea-ice dampens the ocean tide amplitude with the result that global tidal models perform less accurately in the polar regions. This paper presents, a kinematic processing of global positioning system (GPS....... The results show coherence between the GPS buoy measurements, and the tide model. Furthermore, we have proved that the reference ellipsoid of WGS84, can be interpolated to the tidal defined zero level by applying geophysical corrections to the GPS data....

  20. GPs and end of life decisions : views and experiences

    OpenAIRE

    Abela, Jurgen

    2015-01-01

    The views and experiences of GPs with respect to end of life (EoL) care are seldom addressed. The aim of this article is to better understand this aspect of care. A cross-sectional survey of all doctors in the country was designed and set up. The overall response was 396 (39.7%), 160 of which were GPs. 28.7% of GPs received no formal training in palliative medicine. 89.8% of respondents declared that their religion was important in EoL care. 45.3% agreed with the right of a patient to decide ...

  1. Influence of Ephemeris Error on GPS Single Point Positioning Accuracy

    Science.gov (United States)

    Lihua, Ma; Wang, Meng

    2013-09-01

    The Global Positioning System (GPS) user makes use of the navigation message transmitted from GPS satellites to achieve its location. Because the receiver uses the satellite's location in position calculations, an ephemeris error, a difference between the expected and actual orbital position of a GPS satellite, reduces user accuracy. The influence extent is decided by the precision of broadcast ephemeris from the control station upload. Simulation analysis with the Yuma almanac show that maximum positioning error exists in the case where the ephemeris error is along the line-of-sight (LOS) direction. Meanwhile, the error is dependent on the relationship between the observer and spatial constellation at some time period.

  2. GPS operations at Olkiluoto, Kivetty and Romuvaara in 2008

    International Nuclear Information System (INIS)

    Kallio, U.; Ahola, J.; Koivula, H.; Jokela, J.; Poutanen, M.

    2009-09-01

    The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. A total of 26 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 17 campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than 0.20 mm/a. The networks of Kivetty and Romuvaara are quite stable expect one pillar at Romuvaara. There are seven pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined. The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments in connection to the GPS observations. The comparison between the GPS and EDM results can help to fix a possible scale error of the GPS measurements. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003 and now we have computed the first deformation analysis from the six years data. The local crustal deformations have been studied in GeoSatakunta project, too. This GPS network is

  3. GPS operations at Olkiluoto, Kivetty and Romuvaara in 2007

    International Nuclear Information System (INIS)

    Ahola, J.; Koivula, H.; Jokela, J.

    2008-05-01

    The GPS based deformation studies have been made at the investigation areas of Posiva since 1995, when the network of ten GPS pillars was established at Olkiluoto. The network of seven GPS pillars was built at Kivetty and Romuvaara during the year 1996. One pillar in each investigation area belongs to the Finnish permanent GPS network, FinnRef. 24 GPS measurement campaigns have been carried out at Olkiluoto since 1995, and 16 campaigns at Kivetty and Romuvaara. According to the time series of the GPS results 1/3 of the baselines at Olkiluoto have statistically significant change rates. However, the observed movements are smaller than ± 0.20 mm/a. The networks of Kivetty and Romuvaara are quite stabile expect one pillar at Romuvaara. There are five pillars, which have statistically significant horizontal velocities at Olkiluoto. These local velocity components are small but taking into account the standard deviations the largest velocity components seems to be reliably determined (maximum velocity is -0.22 mm/a ± 0.02 mm/a). The uniform scale for the GPS measurements made in different years is the basic condition for reliable results in the deformation analyses. At Olkiluoto a baseline for electronic distance measurements (EDM) was built in 2002. The baseline has been measured using EDM instruments simultaneously with the GPS observations. The comparison between the GPS and EDM results can solve a possible scale error of the GPS. The GPS network at Olkiluoto was extended in 2003. The new pillars were built close to Kuivalahti village and on a small island of Iso Pyrekari. According to the geological evidence it is expected that a fracture zone is located between the new stations, thus enabling the determination of possible deformations along the fracture zone. The new pillars have been observed since 2003, but the time series are still too short for reliable deformation studies. The local crustal deformations have been studied in GeoSatakunta project, too. This

  4. Geomagnetic Storm Impact On GPS Code Positioning

    Science.gov (United States)

    Uray, Fırat; Varlık, Abdullah; Kalaycı, İbrahim; Öǧütcü, Sermet

    2017-04-01

    This paper deals with the geomagnetic storm impact on GPS code processing with using GIPSY/OASIS research software. 12 IGS stations in mid-latitude were chosen to conduct the experiment. These IGS stations were classified as non-cross correlation receiver reporting P1 and P2 (NONCC-P1P2), non-cross correlation receiver reporting C1 and P2 (NONCC-C1P2) and cross-correlation (CC-C1P2) receiver. In order to keep the code processing consistency between the classified receivers, only P2 code observations from the GPS satellites were processed. Four extreme geomagnetic storms October 2003, day of the year (DOY), 29, 30 Halloween Storm, November 2003, DOY 20, November 2004, DOY 08 and four geomagnetic quiet days in 2005 (DOY 92, 98, 99, 100) were chosen for this study. 24-hour rinex data of the IGS stations were processed epoch-by-epoch basis. In this way, receiver clock and Earth Centered Earth Fixed (ECEF) Cartesian Coordinates were solved for a per-epoch basis for each day. IGS combined broadcast ephemeris file (brdc) were used to partly compensate the ionospheric effect on the P2 code observations. There is no tropospheric model was used for the processing. Jet Propulsion Laboratory Application Technology Satellites (JPL ATS) computed coordinates of the stations were taken as true coordinates. The differences of the computed ECEF coordinates and assumed true coordinates were resolved to topocentric coordinates (north, east, up). Root mean square (RMS) errors for each component were calculated for each day. The results show that two-dimensional and vertical accuracy decreases significantly during the geomagnetic storm days comparing with the geomagnetic quiet days. It is observed that vertical accuracy is much more affected than the horizontal accuracy by geomagnetic storm. Up to 50 meters error in vertical component has been observed in geomagnetic storm day. It is also observed that performance of Klobuchar ionospheric correction parameters during geomagnetic storm

  5. Kinematic-PPP using Single/Dual Frequency Observations from (GPS, GLONASS and GPS/GLONASS) Constellations for Hydrography

    Science.gov (United States)

    Farah, Ashraf

    2018-03-01

    Global Positioning System (GPS) technology is ideally suited for inshore and offshore positioning because of its high accuracy and the short observation time required for a position fix. Precise point positioning (PPP) is a technique used for position computation with a high accuracy using a single GNSS receiver. It relies on highly accurate satellite position and clock data that can be acquired from different sources such as the International GNSS Service (IGS). PPP precision varies based on positioning technique (static or kinematic), observations type (single or dual frequency) and the duration of observations among other factors. PPP offers comparable accuracy to differential GPS with safe in cost and time. For many years, PPP users depended on GPS (American system) which considered the solely reliable system. GLONASS's contribution in PPP techniques was limited due to fail in maintaining full constellation. Yet, GLONASS limited observations could be integrated into GPS-based PPP to improve availability and precision. As GLONASS reached its full constellation early 2013, there is a wide interest in PPP systems based on GLONASS only and independent of GPS. This paper investigates the performance of kinematic PPP solution for the hydrographic applications in the Nile river (Aswan, Egypt) based on GPS, GLONASS and GPS/GLONASS constellations. The study investigates also the effect of using two different observation types; single-frequency and dual frequency observations from the tested constellations.

  6. Monitoreo de la calidad de datos GPS continuo: la estacion UNSJ (San Juan, Argentina

    Directory of Open Access Journals (Sweden)

    Alfredo Herrada

    2010-06-01

    Full Text Available Como parte de la red de referencia de operación continua de Argentina, la estación GPS (Global Positioning System denominada UNSJ (Universidad Nacional de San Juan fue establecida en la ciudad de San Juan el 6 de Marzo de 2007. Los datos registrados de UNSJ son ampliamente utilizados en aplicaciones catastrales, y sirven como base para la definición de los marcos de referencia geodésicos nacional y regional. Como una componente fundamental de la infraestructura geodésica, resulta conveniente un eficiente control de calidad de los datos crudos y el monitoreo de la estabilidad de una estación GPS de referencia. En este trabajo se presentan los resultados del control de calidad de las observaciones UNSJ luego de dos anos de operación. Para contro l ar y caracterizar el desempeno del receptor GPS y además el medio ambiente de la estación, se eligieron cuatro índices. Ellos son el número de observaciones, multicamino en L1, multicamino en L2 y ocurrencia de saltos de ciclos. También, se evaluó la estabilidad de largo término de la estación UNSJ a través del análisis de las series temporales de las coordenadas semanales provistas por los centros de cálculo SIRGAS (Sistema de Referencia Geocéntrico para las Américas. Completa este estudio el análisis de las coordenadas calculadas por distintos servicios de procesamiento disponibles en Internet. Nuestros resultados indican que durante el período analizado, el funcionamiento de la estación UNSJ fue satisfactorio, produciendo índices de calidad que son aceptables para estándares internacionales.As a part of the Argentine continuously operating reference station network, a GPS (Global Positioning System station named UNSJ (Universidad Nacional de San Juan was established in San Juan city on 6th March 2007. The recorded data of UNSJ are widely applied to cadastral surveys and serve as the basis for defining national and regional geodetic reference frames. As a key component of the

  7. DOTD standards for GPS data collection accuracy : research project capsule.

    Science.gov (United States)

    2013-12-01

    Global Navigational Satellite Systems (GNSS), which includes GPS technologies : maintained by the United States, are used extensively throughout government : and industry. These technologies continue to revolutionize positional data : collection acti...

  8. Developing a GPS-based truck freight performance measure platform.

    Science.gov (United States)

    2010-05-01

    Although trucks move the largest volume and value of goods in urban areas, relatively little is known about their travel : patterns and how the roadway network performs for trucks. Global positioning systems (GPS) used by trucking : companies to mana...

  9. Wireless GPS fleet tracking system at the University of Albany.

    Science.gov (United States)

    2014-07-01

    This report provides an overview of the project undertaken at the University at Albany to make alternative transportation a more : viable option by implementing a GPS Tracking System on the University bus fleet and broadcasting the bus locations to c...

  10. GPS satellite and receiver instrumental biases estimation using least ...

    Indian Academy of Sciences (India)

    PA) landings. Therefore, GPS augmentation sys- tem is required to provide users with orbit, clock, and ionosphere corrections. The first space-based augmentation system .... detailed structure of the transversal filter consists of 3 basic weight ...

  11. Hurricane Inner-Core Structure as Revealed by GPS Dropwindsondes

    National Research Council Canada - National Science Library

    Leejoice, Robert

    2000-01-01

    New high-resolution information of the vertical thermodynamic and kinematic structure of the hurricane inner-core is now available from aircraft released Global Positioning System (GPS) dropwindsondes...

  12. DARPA looks beyond GPS for positioning, navigating, and timing

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, David

    2014-10-01

    Cold-atom interferometry, microelectromechanical systems, signals of opportunity, and atomic clocks are some of the technologies the defense agency is pursuing to provide precise navigation when GPS is unavailable.

  13. Global Positioning System (GPS) Receiver Design For Multipaths Mitigation

    National Research Council Canada - National Science Library

    Gadallah, El-Sayed

    1998-01-01

    .... This research introduces a new estimator that can detect the presence of multipath, can determine the unknown number of multipath components and can estimate multipath parameters in the GPS receiver...

  14. Using cluster analysis to organize and explore regional GPS velocities

    Science.gov (United States)

    Simpson, Robert W.; Thatcher, Wayne; Savage, James C.

    2012-01-01

    Cluster analysis offers a simple visual exploratory tool for the initial investigation of regional Global Positioning System (GPS) velocity observations, which are providing increasingly precise mappings of actively deforming continental lithosphere. The deformation fields from dense regional GPS networks can often be concisely described in terms of relatively coherent blocks bounded by active faults, although the choice of blocks, their number and size, can be subjective and is often guided by the distribution of known faults. To illustrate our method, we apply cluster analysis to GPS velocities from the San Francisco Bay Region, California, to search for spatially coherent patterns of deformation, including evidence of block-like behavior. The clustering process identifies four robust groupings of velocities that we identify with four crustal blocks. Although the analysis uses no prior geologic information other than the GPS velocities, the cluster/block boundaries track three major faults, both locked and creeping.

  15. A Usability Survey of GPS Avionics Equipment: Some Preliminary Findings

    National Research Council Canada - National Science Library

    Joseph, Kurt

    1999-01-01

    The rapid introduction of Global Positioning System (GPS) receivers for airborne navigation has outpaced the capacity of international aviation authorities to resolve human factors issues that concern safe and efficient use of such devices...

  16. GPs' Perceptions of Cardiovascular Risk and Views on Patient Compliance

    DEFF Research Database (Denmark)

    Barfoed, Benedicte Marie Lind; Jarbøl, Dorte Ejg; Paulsen, Maja Skov

    2015-01-01

    Objective. General practitioners' (GPs') perception of risk is a cornerstone of preventive care. The aims of this interview study were to explore GPs' professional and personal attitudes and experiences regarding treatment with lipid-lowering drugs and their views on patient compliance. Methods....... The material was drawn from semistructured qualitative interviews. We sampled GPs purposively from ten selected practices, ensuring diversity of demographic, professional, and personal characteristics. The GPs were encouraged to describe examples from their own practices and reflect on them and were informed...... that the focus was their personal attitudes and experiences. Systematic text condensation was applied for analysis in order to uncover the concepts and themes. Results. The analysis revealed the following 3 main themes: (1) use of cardiovascular guidelines and risk assessment tools, (2) strategies for managing...

  17. NavCube: A fully realized modernized GPS receiver

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this IRAD project is to complete the technology development of the modernized Navigator-SpaceCube GPS receiver (named the NavCube), enabling a potential...

  18. A Mobile GPS Application: Mosque Tracking with Prayer Time Synchronization

    Science.gov (United States)

    Hashim, Rathiah; Ikhmatiar, Mohammad Sibghotulloh; Surip, Miswan; Karmin, Masiri; Herawan, Tutut

    Global Positioning System (GPS) is a popular technology applied in many areas and embedded in many devices, facilitating end-users to navigate effectively to user's intended destination via the best calculated route. The ability of GPS to track precisely according to coordinates of specific locations can be utilized to assist a Muslim traveler visiting or passing an unfamiliar place to find the nearest mosque in order to perform his prayer. However, not many techniques have been proposed for Mosque tracking. This paper presents the development of GPS technology in tracking the nearest mosque using mobile application software embedded with the prayer time's synchronization system on a mobile application. The prototype GPS system developed has been successfully incorporated with a map and several mosque locations.

  19. SMEX02 Airborne GPS Bistatic Radar Data, Iowa

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains measurements of Global Positioning System (GPS) signals reflected from the Earth’s surface and collected on an airborne platform. The...

  20. GPS-based satellite tracking system for precise positioning

    Science.gov (United States)

    Yunck, T. P.; Melbourne, W. G.; Thornton, C. L.

    1985-01-01

    NASA is developing a Global Positioning System (GPS) based measurement system to provide precise determination of earth satellite orbits, geodetic baselines, ionospheric electron content, and clock offsets between worldwide tracking sites. The system will employ variations on the differential GPS observing technique and will use a network of nine fixed ground terminals. Satellite applications will require either a GPS flight receiver or an on-board GPS beacon. Operation of the system for all but satellite tracking will begin by 1988. The first major satellite application will be a demonstration of decimeter accuracy in determining the altitude of TOPEX in the early 1990's. By then the system is expected to yield long-baseline accuracies of a few centimeters and instantaneous time synchronization to 1 ns.

  1. A New Indoor Positioning System Architecture Using GPS Signals.

    Science.gov (United States)

    Xu, Rui; Chen, Wu; Xu, Ying; Ji, Shengyue

    2015-04-29

    The pseudolite system is a good alternative for indoor positioning systems due to its large coverage area and accurate positioning solution. However, for common Global Positioning System (GPS) receivers, the pseudolite system requires some modifications of the user terminals. To solve the problem, this paper proposes a new pseudolite-based indoor positioning system architecture. The main idea is to receive real-world GPS signals, repeat each satellite signal and transmit those using indoor transmitting antennas. The transmitted GPS-like signal can be processed (signal acquisition and tracking, navigation data decoding) by the general receiver and thus no hardware-level modification on the receiver is required. In addition, all Tx can be synchronized with each other since one single clock is used in Rx/Tx. The proposed system is simulated using a software GPS receiver. The simulation results show the indoor positioning system is able to provide high accurate horizontal positioning in both static and dynamic situations.

  2. Deployment of Autonomous GPS Stations in Marie Byrd Land, Antartica

    Science.gov (United States)

    Donnellan, A.; Luyendyk, B.; Smith, M.; Dace, G.

    1999-01-01

    During the 1998-1999 Antarctic field season, we installed three autonomous GPS stations in Marie Byrd Land, West Antarctica to measure glacio-isostatic rebound and rates of spreading across the West Antartic Rift System.

  3. GNSS global navigation satellite systems : GPS, GLONASS, Galileo, and more

    CERN Document Server

    Hofmann-Wellenhof, Bernhard; Wasle, Elmar

    2008-01-01

    This book is an extension to the acclaimed scientific bestseller "GPS - Theory and Practice". It covers Global Navigation Satellite Systems (GNSS) and includes the Russian GLONASS, the European system Galileo, and additional systems.

  4. 77 FR 23668 - GPS Satellite Simulator Working Group Notice of Meeting

    Science.gov (United States)

    2012-04-20

    ... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Working Group Notice of... inform the public that the Global Positioning Systems (GPS) Directorate will be hosting an open GPS Satellite Simulator Working Group (SSWG) meeting for manufacturers of GPS constellation simulators utilized...

  5. Measurements of ionospheric TEC in the direction of GPS satellites and comparison with three ionospheric models

    Directory of Open Access Journals (Sweden)

    E. Zuccheretti

    1997-06-01

    Full Text Available The IEN Galileo Ferraris uses GPS for time and frequency synchronization. To obtain high performance it is important to reduce the error due to the ionospheric time-delay in GPS measurements. Evaluations of TEC in the direction of GPS satellites, obtained from three different ionospheric models, have been compared with corresponding measurements by GPS signal.

  6. Exatidão de posicionamento de um receptor GPS, operando sob diferentes coberturas vegetais Evaluation of the accuracy of positioning a GPS receiver operating under different vegetation covers

    Directory of Open Access Journals (Sweden)

    Rubens Angulo Filho

    2002-01-01

    Full Text Available Para avaliar a exatidão de posicionamento planimétrico do receptor GPS Trimble/Pro-XL, operando sob diferentes condições de cobertura vegetal (pastagem, seringueira, eucalipto e pinus, o equipamento foi posicionado alternadamente sobre 6 pontos, locados ao acaso nas áreas de estudo, variando o tempo de permanência (1 , 5 e 10 min mas com a mesma taxa de aquisição de dados (1 s fazendo-se, posteriormente, a correção diferencial (DGPS pós-processada dos dados. Os pontos também tiveram suas coordenadas levantadas pelo método topográfico, segundo a NBR 13133 - Execução de Levantamento Topográfico, para fins de comparação. De acordo com o método empregado e os resultados obtidos, foi possível separar as exatidões de posicionamento planimétrico, conforme o tipo de cobertura vegetal, em dois grupos: sem e com cobertura arbórea confirmando, assim, a interferência do dossel na recepção dos sinais emitidos pelos satélites GPS. O aumento do tempo de permanência melhorou a exatidão de posicionamento planimétrico, o que ratifica a escolha da metodologia de levantamento como sendo fundamental para a obtenção de bons resultados de posicionamento.To evaluate planimetric positioning accuracy of a GPS receiver (Trimble/Pro-XL, operating under different conditions of vegetation cover (pasture, rubber trees, eucalyptus and pine trees, 6 control points were located randomly in the study area. For comparison, their coordinates were first obtained by a conventional surveying method, according to NBR 13133 of Brazilian Surveying Standards. Afterwards, the GPS receiver was positioned on those control points, maintaining the acquisition rate of 1 s while changing the time for 1, 5 and 10 min, the DGPS method was used to correct the positioning coordinate data. According to the methodology applied and the results obtained, it was possible to distinguish planimetric positioning accuracy, according to the vegetation cover, in two groups

  7. Relationships between GPS-signal propagation errors and EISCAT observations

    Directory of Open Access Journals (Sweden)

    N. Jakowski

    1996-12-01

    Full Text Available When travelling through the ionosphere the signals of space-based radio navigation systems such as the Global Positioning System (GPS are subject to modifications in amplitude, phase and polarization. In particular, phase changes due to refraction lead to propagation errors of up to 50 m for single-frequency GPS users. If both the L1 and the L2 frequencies transmitted by the GPS satellites are measured, first-order range error contributions of the ionosphere can be determined and removed by difference methods. The ionospheric contribution is proportional to the total electron content (TEC along the ray path between satellite and receiver. Using about ten European GPS receiving stations of the International GPS Service for Geodynamics (IGS, the TEC over Europe is estimated within the geographic ranges -20°≤ λ ≤40°E and 32.5°≤ Φ ≤70°N in longitude and latitude, respectively. The derived TEC maps over Europe contribute to the study of horizontal coupling and transport proces- ses during significant ionospheric events. Due to their comprehensive information about the high-latitude ionosphere, EISCAT observations may help to study the influence of ionospheric phenomena upon propagation errors in GPS navigation systems. Since there are still some accuracy limiting problems to be solved in TEC determination using GPS, data comparison of TEC with vertical electron density profiles derived from EISCAT observations is valuable to enhance the accuracy of propagation-error estimations. This is evident both for absolute TEC calibration as well as for the conversion of ray-path-related observations to vertical TEC. The combination of EISCAT data and GPS-derived TEC data enables a better understanding of large-scale ionospheric processes.

  8. GPs' perceptions of workload in England: a qualitative interview study.

    Science.gov (United States)

    Croxson, Caroline Hd; Ashdown, Helen F; Hobbs, Fd Richard

    2017-02-01

    GPs report the lowest levels of morale among doctors, job satisfaction is low, and the GP workforce is diminishing. Workload is frequently cited as negatively impacting on commitment to a career in general practice, and many GPs report that their workload is unmanageable. To gather an in-depth understanding of GPs' perceptions and attitudes towards workload. All GPs working within NHS England were eligible. Advertisements were circulated via regional GP e-mail lists and national social media networks in June 2015. Of those GPs who responded, a maximum-variation sample was selected until data saturation was reached. Semi-structured, qualitative interviews were conducted. Data were analysed thematically. In total, 171 GPs responded, and 34 were included in this study. GPs described an increase in workload over recent years, with current working days being long and intense, raising concerns over the wellbeing of GPs and patients. Full-time partnership was generally not considered to be possible, and many participants felt workload was unsustainable, particularly given the diminishing workforce. Four major themes emerged to explain increased workload: increased patient needs and expectations; a changing relationship between primary and secondary care; bureaucracy and resources; and the balance of workload within a practice. Continuity of care was perceived as being eroded by changes in contracts and working patterns to deal with workload. This study highlights the urgent need to address perceived lack of investment and clinical capacity in general practice, and suggests that managing patient expectations around what primary care can deliver, and reducing bureaucracy, have become key issues, at least until capacity issues are resolved. © British Journal of General Practice 2017.

  9. Routing Unmanned Vehicles in GPS-Denied Environments

    OpenAIRE

    Sundar, Kaarthik; Misra, Sohum; Rathinam, Sivakumar; Sharma, Rajnikant

    2017-01-01

    Most of the routing algorithms for unmanned vehicles, that arise in data gathering and monitoring applications in the literature, rely on the Global Positioning System (GPS) information for localization. However, disruption of GPS signals either intentionally or unintentionally could potentially render these algorithms not applicable. In this article, we present a novel method to address this difficulty by combining methods from cooperative localization and routing. In particular, the article...

  10. Environmental radiation monitoring system with GPS (global positioning system)

    International Nuclear Information System (INIS)

    Komoto, Itsuro

    2000-01-01

    This system combines a radiation monitoring car with GPS and a data processor (personal computer). It distributes the position information acquired through GPS to the data such as measured environmental radiation dose rate and energy spectrum. It also displays and edits the data for each measuring position on a map. Transmitting the data to the power station through mobile phone enables plan managers to easily monitor the environmental radiation dose rate nearby and proper emergency monitoring. (author)

  11. Challenges and advantages of using GPS data in outdoor advertisement

    OpenAIRE

    Hecker, Dirk; Körner, Christine; May, Michael

    2011-01-01

    A growing number of companies use mobility data in their day-to-day business. Especially in the area of outdoor advertising, GPS devices have been successfully applied in order to measure poster performance in recent years. Based on personal mobility traces, the quality and precision of performance measures has increased significantly. However, the usage of GPS technology poses several challenges when applied to critical business processes. We will present several challenges and solutions whi...

  12. Software Defined GPS Receiver for International Space Station

    Science.gov (United States)

    Duncan, Courtney B.; Robison, David E.; Koelewyn, Cynthia Lee

    2011-01-01

    JPL is providing a software defined radio (SDR) that will fly on the International Space Station (ISS) as part of the CoNNeCT project under NASA's SCaN program. The SDR consists of several modules including a Baseband Processor Module (BPM) and a GPS Module (GPSM). The BPM executes applications (waveforms) consisting of software components for the embedded SPARC processor and logic for two Virtex II Field Programmable Gate Arrays (FPGAs) that operate on data received from the GPSM. GPS waveforms on the SDR are enabled by an L-Band antenna, low noise amplifier (LNA), and the GPSM that performs quadrature downconversion at L1, L2, and L5. The GPS waveform for the JPL SDR will acquire and track L1 C/A, L2C, and L5 GPS signals from a CoNNeCT platform on ISS, providing the best GPS-based positioning of ISS achieved to date, the first use of multiple frequency GPS on ISS, and potentially the first L5 signal tracking from space. The system will also enable various radiometric investigations on ISS such as local multipath or ISS dynamic behavior characterization. In following the software-defined model, this work will create a highly portable GPS software and firmware package that can be adapted to another platform with the necessary processor and FPGA capability. This paper also describes ISS applications for the JPL CoNNeCT SDR GPS waveform, possibilities for future global navigation satellite system (GNSS) tracking development, and the applicability of the waveform components to other space navigation applications.

  13. GPS Estimates of Integrated Precipitable Water Aid Weather Forecasters

    Science.gov (United States)

    Moore, Angelyn W.; Gutman, Seth I.; Holub, Kirk; Bock, Yehuda; Danielson, David; Laber, Jayme; Small, Ivory

    2013-01-01

    Global Positioning System (GPS) meteorology provides enhanced density, low-latency (30-min resolution), integrated precipitable water (IPW) estimates to NOAA NWS (National Oceanic and Atmospheric Adminis tration Nat ional Weather Service) Weather Forecast Offices (WFOs) to provide improved model and satellite data verification capability and more accurate forecasts of extreme weather such as flooding. An early activity of this project was to increase the number of stations contributing to the NOAA Earth System Research Laboratory (ESRL) GPS meteorology observing network in Southern California by about 27 stations. Following this, the Los Angeles/Oxnard and San Diego WFOs began using the enhanced GPS-based IPW measurements provided by ESRL in the 2012 and 2013 monsoon seasons. Forecasters found GPS IPW to be an effective tool in evaluating model performance, and in monitoring monsoon development between weather model runs for improved flood forecasting. GPS stations are multi-purpose, and routine processing for position solutions also yields estimates of tropospheric zenith delays, which can be converted into mm-accuracy PWV (precipitable water vapor) using in situ pressure and temperature measurements, the basis for GPS meteorology. NOAA ESRL has implemented this concept with a nationwide distribution of more than 300 "GPSMet" stations providing IPW estimates at sub-hourly resolution currently used in operational weather models in the U.S.

  14. Application of GPS systems on a mobile robot

    Science.gov (United States)

    Cao, Peter; Saxena, Mayank; Tedder, Maurice; Mischalske, Steve; Hall, Ernest L.

    2001-10-01

    The purpose of this paper is to describe the use of Global Positioning Systems (GPS) as geographic information and navigational system for a ground based mobile robot. Several low cost wireless systems are now available for a variety of innovative automobile applications including location, messaging and tracking and security. Experiments were conducted with a test bed mobile robot, Bearcat II, for point-to-point motion using a Motorola GPS in June 2001. The Motorola M12 Oncore GPS system is connected to the Bearcat II main control computer through a RS232 interface. A mapping program is used to define a desired route. Then GPS information may be displayed for verification. However, the GPS information is also used to update the control points of the mobile robot using a reinforcement learning method. Local position updates are also used when found in the environment. The significance of the method is in extending the use of GPS to local vehicle control that requires more resolution that is available from the raw data using the adaptive control method.

  15. Profile of English salaried GPs: labour mobility and practice performance.

    Science.gov (United States)

    Ding, Alexander; Hann, Mark; Sibbald, Bonnie

    2008-01-01

    Recent national policy changes have provided greater flexibility in GPs' contracts. One such policy is salaried employment, which offers reduced hours and freedom from out-of-hours and administrative responsibilities, aimed at improving recruitment and retention in a labour market facing regional shortages. To profile salaried GPs and assess their mobility within the labour market. Serial cross-sectional study. All GPs practising in England during the years 1996/1997, 2000/2001, and 2004/2005. Descriptive analyses, logistic regression. Salaried GPs tended to be either younger ( or =65 years), female, or overseas-qualified; they favoured part-time working and personal medical services contracts. Salaried GPs were more mobile than GP principals, and have become increasingly so, despite a trend towards reduced overall mobility in the GP workforce. Practices with salaried GPs scored more Quality and Outcomes Framework points and were located in slightly more affluent areas. Salaried status appears to have reduced limitations in the labour market, leading to better workforce deployment from a GP's perspective. However, there is no evidence to suggest it has relieved inequalities in GP distribution.

  16. GPs' perceptions of resilience training: a qualitative study.

    Science.gov (United States)

    Cheshire, Anna; Hughes, John; Lewith, George; Panagioti, Maria; Peters, David; Simon, Chantal; Ridge, Damien

    2017-10-01

    GPs are reporting increasing levels of burnout, stress, and job dissatisfaction, and there is a looming GP shortage. Promoting resilience is a key strategy for enhancing the sustainability of the healthcare workforce and improving patient care. To explore GPs' perspectives on the content, context, and acceptability of resilience training programmes in general practice, in order to build more effective GP resilience programmes. This was a qualitative study of the perspectives of GPs currently practising in England. GPs were recruited through convenience sampling, and data were collected from two focus groups ( n = 15) and one-to-one telephone interviews ( n = 7). A semi-structured interview approach was used and data were analysed using thematic analysis. Participants perceived resilience training to be potentially of value in ameliorating workplace stresses. Nevertheless, uncertainty was expressed regarding how best to provide training for stressed GPs who have limited time. Participants suspected that GPs most likely to benefit from resilience training were the least likely to engage, as stress and being busy worked against engagement. Conflicting views were expressed about the most suitable training delivery method for promoting better engagement. Participants also emphasised that training should not only place the focus on the individual, but also focus on organisation issues. A multimodal, flexible approach based on individual needs and learning aims, including resilience workshops within undergraduate training and in individual practices, is likely to be the optimal way to promote resilience. © British Journal of General Practice 2017.

  17. Soil Moisture Retrieval Based on GPS Signal Strength Attenuation

    Directory of Open Access Journals (Sweden)

    Franziska Koch

    2016-07-01

    Full Text Available Soil moisture (SM is a highly relevant variable for agriculture, the emergence of floods and a key variable in the global energy and water cycle. In the last years, several satellite missions have been launched especially to derive large-scale products of the SM dynamics on the Earth. However, in situ validation data are often scarce. We developed a new method to retrieve SM of bare soil from measurements of low-cost GPS (Global Positioning System sensors that receive the freely available GPS L1-band signals. The experimental setup of three GPS sensors was installed at a bare soil field at the German Weather Service (DWD in Munich for almost 1.5 years. Two GPS antennas were installed within the soil column at a depth of 10 cm and one above the soil. SM was successfully retrieved based on GPS signal strength losses through the integral soil volume. The results show high agreement with measured and modelled SM validation data. Due to its non-destructive, cheap and low power setup, GPS sensor networks could also be used for potential applications in remote areas, aiming to serve as satellite validation data and to support the fields of agriculture, water supply, flood forecasting and climate change.

  18. Application of GPS in a high precision engineering survey network

    International Nuclear Information System (INIS)

    Ruland, R.; Leick, A.

    1985-04-01

    A GPS satellite survey was carried out with the Macrometer to support construction at the Stanford Linear Accelerator Center (SLAC). The network consists of 16 stations of which 9 stations were part of the Macrometer network. The horizontal and vertical accuracy of the GPS survey is estimated to be 1 to 2 mm and 2 to 3 mm respectively. The horizontal accuracy of the terrestrial survey, consisting of angles and distances, equals that of the GPS survey only in the ''loop'' portion of the network. All stations are part of a precise level network. The ellipsoidal heights obtained from the GPS survey and the orthometric heights of the level network are used to compute geoid undulations. A geoid profile along the linac was computed by the National Geodetic Survey in 1963. This profile agreed with the observed geoid within the standard deviation of the GPS survey. Angles and distances were adjusted together (TERRA), and all terrestrial observations were combined with the GPS vector observations in a combination adjustment (COMB). A comparison of COMB and TERRA revealed systematic errors in the terrestrial solution. A scale factor of 1.5 ppM +- .8 ppM was estimated. This value is of the same magnitude as the over-all horizontal accuracy of both networks. 10 refs., 3 figs., 5 tabs

  19. Kinematic GPS survey as validation of LIDAR strips accuracy

    Directory of Open Access Journals (Sweden)

    C. Gordini

    2006-06-01

    Full Text Available As a result of the catastrophic hydrogeological events which occurred in May 1998 in Campania, in the south of Italy, the distinctive features of airborne laser scanning mounted on a helicopter were used to survey the landslides at Sarno and Quindici. In order to survey the entire zone of interest, approximately 21 km2, it was necessary to scan 12 laser strips. Many problems arose during the survey: difficulties in receiving the GPS signal, complex terrain features and unfavorable atmospheric conditions. These problems were investigated and it emerged that one of the most influential factors is the quality of GPS signals. By analysing the original GPS data, the traces obtained by fixing phase ambiguity with an On The Fly (OTF algorithm were isolated from those with smoothed differential GPS solution (DGPS. Processing and analysis of laser data showed that not all the overlapping laser strips were congruent with each other. Since an external survey to verify the laser data accuracy was necessary, it was decided to utilize the kinematic GPS technique. The laser strips were subsequently adjusted, using the kinematic GPS data as reference points. Bearing in mind that in mountainous areas like the one studied here it is not possible to obtain nominal precision and accuracy, a good result was nevertheless obtained with a Digital Terrain Model (DTM of all the zones of interest.

  20. Studying Landslide Displacements in Megamendung (Indonesia Using GPS Survey Method

    Directory of Open Access Journals (Sweden)

    Hasanuddin Z. Abidin

    2004-11-01

    Full Text Available Landslide is one of prominent geohazards that frequently affects Indonesia, especially in the rainy season. It destroys not only environment and property, but usually also causes deaths. Landslide monitoring is therefore very crucial and should be continuously done. One of the methods that can have a contribution in studying landslide phenomena is repeated GPS survey method. This paper presents and discusses the operational performances, constraints and results of GPS surveys conducted in a well known landslide prone area in West Java (Indonesia, namely Megamendung, the hilly region close to Bogor. Three GPS surveys involving 8 GPS points have been conducted, namely on April 2002, May 2003 and May 2004, respectively. The estimated landslide displacements in the area are relatively quite large in the level of a few dm to a few m. Displacements up to about 2-3 m were detected in the April 2002 to May 2003 period, and up to about 3-4 dm in the May 2003 to May 2004 period. In both periods, landslides in general show the northwest direction of displacements. Displacements vary both spatially and temporally. This study also suggested that in order to conclude the existence of real and significant displacements of GPS points, the GPS estimated displacements should be subjected to three types of testing namely: the congruency test on spatial displacements, testing on the agreement between the horizontal distance changes with the predicted direction of landslide displacement, and testing on the consistency of displacement directions on two consecutive periods.

  1. Development of GPS data remote retrieval system using wireless LAN

    Directory of Open Access Journals (Sweden)

    Koichiro Doi

    2012-11-01

    Full Text Available A remote retrieval system, using a wireless LAN, was developed to retrieve dual-frequency GPS data. The system consists of a ground observation unit (comprising a dual-frequency GPS logger and a data transmission unit and a data retrieval unit. In this system, we use the ZigBee communication protocol to transmit control commands (2.4 GHz, 250 Kbps and a wireless LAN communication to transmit GPS data (2.4 GHz, 54 Mbps. Data of every 30 seconds to transmit to the data retrieval unit are re-sampled from 1-second data at 00 UT each day. We conducted three data-transmission tests with the system: (1 a ground data retrieval test, (2 a data retrieval test from the atmosphere of a few hundred meters high using a small unmanned aircraft, and (3 actual GPS-data retrieval tests from a GPS buoy deployed on sea ice at Nisi-no-ura Cove, Syowa Station, Antarctica. In test (1, we successfully received all the data from the ground observation unit when situated at distances of less than 400 m from the data retrieval unit. In test (2, we obtained approximately 24.5 MB of data from the aircraft at heights of less than 250 m. In test (3, we obtained approximately 23.5 MB of data from the GPS buoy within 10 minutes. The proposed system has the advantage of enabling continuous measurements without aborting the measurement at the data retrievals.

  2. The Volpe Center GPS Adjacent Band Compatibility Program Plan : GPS Adjacent Band Compatibility Workshop, Volpe Center, Cambridge MA

    Science.gov (United States)

    2014-09-18

    Approach to DOT GPS Adjacent Band Compatibility Assessment. Identify forums and provide public outreach to make sure the progress and work are as open and transparent as possible. Develop an implementation plan that incorporates aspects from the DOT ...

  3. Development of position measuring technology by GPS; GPS ni yoru sokui gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishizaki, T [Ministry of Transportation, Tokyo (Japan)

    1994-07-25

    With regard to the GPS (global positioning system) which uses the satellites launched and administered by the U.S.A. and has been utilized worldwide for ships, automobiles and geodetic surveys in recent years, Ministry of Transport started investigation and research on the application of its position measuring system from FY 1989. In this fiscal year, a study on position measuring methods and selection of the position measuring system to be developed were made, in FY 1991, the real-time functioning and track display were developed, in FY 1992, the initialization aboard the ship, the measure to prevent cycle slip, and the radio data communication technology were developed, and in FY 1993, a long term demonstration experiment presuming its practical use was conducted attaining the expected purpose. In this article, the developed real-time kinematic position measuring system is introduced. Regarding the position measuring methods by the GPS, there are the one point position measuring method and the relative position measuring method. Regarding this newly developed position measuring device, its application to work ships and structures can be considered in various ways. 4 figs.

  4. GPs should evaluate all children following UTI.

    Science.gov (United States)

    Hutchings, Frances; Jadresić, Lyda

    2010-01-01

    Ten per cent of girls and 3% of boys will have had a UTI by 16 years of age. The majority are acute, isolated illnesses that resolve quickly, with no long-term implications for the patient. However, UTIs may be associated with underlying congenital abnormalities, and recurrent infections can lead to renal scarring. UTI is defined as bacteriuria in the presence of symptoms. Asymptomatic bacteriuria does not require treatment or investigation. The presentation of UTI is extremely variable. The only way to differentiate a UTI from a viral infection is by testing the urine and this should be carried out within 24 hours in children with non-specific fever. UTIs can also present with vomiting, failure to thrive or persistent irritability. A urine infection in the presence of any of the above symptoms is a pyelonephritis (upper UTI). Children may also present with classical symptoms of cystitis (lower UTI) such as urinary frequency, dysuria and abdominal pain. Most children with UTI, even if febrile, can be managed in the community. If the initial assessment shows a high risk of serious illness, there should be an urgent referral to a paediatrician. The same applies to infants under three months with suspected UTI. It is better to obtain a urine sample by the clean catch method, rather than using urine pads or bags. Leucocyte esterase and nitrite dipsticks are not reliable in children under three, so a negative dipstick does not rule out UTI. Not every child needs to be referred after a first UTI. However, they should all be evaluated to help determine which require renal imaging as well as identifying triggers for recurrence. GPs are central to the identification of children at risk of renal pathology. All children who are diagnosed and treated for a UTI must be assessed for risk of renal abnormalities and/or recurrence.

  5. Status of Precise Orbit Determination for Jason-2 Using GPS

    Science.gov (United States)

    Melachroinos, S.; Lemoine, F. G.; Zelensky, N. P.; Rowlands, D. D.; Pavlis, D. E.

    2011-01-01

    The JASON-2 satellite, launched in June 2008, is the latest follow-on to the successful TOPEX/Poseidon (T/P) and JASON-I altimetry missions. JASON-2 is equipped with a TRSR Blackjack GPS dual-frequency receiver, a laser retroreflector array, and a DORIS receiver for precise orbit determination (POD). The most recent time series of orbits computed at NASA GSFC, based on SLR/DORIS data have been completed using both ITRF2005 and ITRF2008. These orbits have been shown to agree radially at 1 cm RMS for dynamic vs SLRlDORIS reduced-dynamic orbits and in comparison with orbits produced by other analysis centers (Lemoine et al., 2010; Zelensky et al., 2010; Cerri et al., 2010). We have recently upgraded the GEODYN software to implement model improvements for GPS processing. We describe the implementation of IGS standards to the Jason2 GEODYN GPS processing, and other dynamical and measurement model improvements. Our GPS-only JASON-2 orbit accuracy is assessed using a number of tests including analysis of independent SLR and altimeter crossover residuals, orbit overlap differences, and direct comparison to orbits generated at GSFC using SLR and DORIS tracking, and to orbits generated externally at other centers. Tests based on SLR and the altimeter crossover residuals provide the best performance indicator for independent validation of the NASAlGSFC GPS-only reduced dynamic orbits. For the ITRF2005 and ITRF2008 implementation of our GPS-only obits we are using the IGS05 and IGS08 standards. Reduced dynamic versus dynamic orbit differences are used to characterize the remaining force model error and TRF instability. We evaluate the GPS vs SLR & DORIS orbits produced using the GEODYN software and assess in particular their consistency radially and the stability of the altimeter satellite reference frame in the Z direction for both ITRF2005 and ITRF2008 as a proxy to assess the consistency of the reference frame for altimeter satellite POD.

  6. Integrating GIS and GPS in environmental remediation oversight

    International Nuclear Information System (INIS)

    Kaletsky, K.; Earle, J.R.; Schneider, T.A.

    1996-01-01

    This paper presents findings on Ohio EPA Office of Federal Facilities Oversight's (OFFO) use of GIS and GPS for environmental remediation oversight at the U.S. Department of Energy's (DOE) Fernald Site. The Fernald site is a former uranium metal production facility within DOE's nuclear weapons complex. Significant uranium contamination of soil and groundwater is being remediated under state and federal regulations. OFFO uses GIS/GPS to enhance environmental monitoring and remediation oversight. These technologies are utilized within OFFO's environmental monitoring program for sample location and parameter selection, data interpretation and presentation. GPS is used to integrate sample data into OFFO's GIS and for permanently linking precise and accurate geographic data to samples and waste units. It is important to identify contamination geographically as all visual references (e.g., buildings, infrastructure) will be removed during remediation. Availability of the GIS allows OFFO to perform independent analysis and review of DOE contractor generated data, models, maps, and designs. This ability helps alleviate concerns associated with open-quotes black boxclose quotes models and data interpretation. OFFO's independent analysis has increased regulatory confidence and the efficiency of design reviews. GIS/GPS technology allows OFFO to record and present complex data in a visual format aiding in stakeholder education and awareness. Presented are OFFO's achievements within the aforementioned activities and some reasons learned in implementing the GIS/GPS program. OFFO's two years of GIS/GPS development have resulted in numerous lessons learned and ideas for increasing effectiveness through the use of GIS/GPS

  7. Climatology of GPS signal loss observed by Swarm satellites

    Directory of Open Access Journals (Sweden)

    C. Xiong

    2018-04-01

    Full Text Available By using 3-year global positioning system (GPS measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20° magnetic latitude (MLAT and high latitudes above 60° MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20°, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver.

  8. Climatology of GPS signal loss observed by Swarm satellites

    Science.gov (United States)

    Xiong, Chao; Stolle, Claudia; Park, Jaeheung

    2018-04-01

    By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20° magnetic latitude (MLAT) and high latitudes above 60° MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20°, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver.

  9. Assessment of 3D hydrologic deformation using GRACE and GPS

    Science.gov (United States)

    Watson, C. S.; Tregoning, P.; Fleming, K.; Burgette, R. J.; Featherstone, W. E.; Awange, J.; Kuhn, M.; Ramillien, G.

    2009-12-01

    Hydrological processes cause variations in gravitational potential and surface deformations, both of which are detectable with ever increasing precision using space geodetic techniques. By comparing the elastic deformation computed from continental water load estimates derived from the Gravity Recovery and Climate Experiment (GRACE), with three-dimensional surface deformation derived from GPS observations, there is clear potential to better understand global to regional hydrological processes, in addition to acquiring further insight into the systematic error contributions affecting each space geodetic technique. In this study, we compare elastic deformation derived from water load estimates taken from the CNES, CSR, GFZ and JPL time variable GRACE fields. We compare these surface displacements with those derived at a global network of GPS sites that have been homogeneously reprocessed in the GAMIT/GLOBK suite. We extend our comparison to include a series of different GPS solutions, with each solution only subtly different based on the methodology used to down weight the height component in realizing site coordinates on the terrestrial reference frame. Each of the GPS solutions incorporate modeling of atmospheric loading and utilization of the VMF1 and a priori zenith hydrostatic delays derived via ray tracing through ECMWF meteorological fields. The agreement between GRACE and GPS derived deformations is not limited to the vertical component, with excellent agreement in the horizontal component across areas where large hydrologic signals occur over broad spatial scales (with correlation in horizontal components as high as 0.9). Agreement is also observed at smaller scales, including across Europe. These comparisons assist in understanding the magnitude of current error contributions within both space geodetic techniques. With the emergence of homogeneously reprocessed GPS time series spanning the GRACE mission, this technique offers one possible means of

  10. O GPS e a velocidade constante da luz

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    Paul Marmet

    2000-05-01

    Full Text Available As transformações de Lorentz e a relatividade especial são incapazes de fornecer uma explicação física realística do comportamento da matéria e da luz. Mostraremos aqui que todos esses fenômenos podem ser explicados usando-se a física de Newton e a conservação da massa-energia, sem apelar para a contração espacial ou a dilatação do tempo. Sabemos que o princípio de conservação da massa-energia requer que os relógios funcionem mais devagar em um referencial móvel, e que os corpos físicos tornam-se maiores devido ao acréscimo do raio de Bohr. Estes resultados nos permitem levantar a seguinte questão: A luz viaja com respeito a quê? Por exemplo, quando nos distanciamos a uma velocidade v de uma fonte emissora de luz, que, por sua vez, se desloca com velocidade c, o movimento relativo da radiação é dado por um deslocamento Doppler. Como podemos explicar logicamente que estes fótons parecem chegar até nós a uma velocidade c e não a uma velocidade (c – v? A explicação convencional remete à relatividade especial, mas isto implica em uma esotérica distorção espaço-temporal, que não é compatível com a lógica. Este artigo fornece uma explicação física de como a velocidade da luz é realmente (c – v com respeito ao observador, mesmo se as ferramentas do observador sempre meçam a velocidade representada pelo número c. Explicamos como este problema é crucial no Global Positioning System (GPS – Sistema de Posicionamento Global e na sincronização dos relógios. As transformações de Lorentz tornam-se desnecessárias. Esta aparente constância da velocidade da luz com respeito a um referencial móvel é a mais fascinante ilusão na ciência.

  11. Earth tide effects on kinematic/static GPS positioning in Denmark and Greenland

    DEFF Research Database (Denmark)

    Xu, G.C.; Knudsen, Per

    2000-01-01

    A detailed Study of the Earth tide effects on the GPS kinematic/static positioning is presented in this paper by using theoretical Earth tide computation and practical GPS data processing. Tidal effects could reach up to 30 cm in Denmark and Greenland depending on the measuring time...... and the position of reference station. With a baseline less than 80 km, the difference of the Earth tide effects could reach more than 5 mm. So, in precise applications of GPS positioning, the Earth tide effect has to be taken into account even for a relative small local GPS network. Several examples are given...... for demonstrating that the Earth tide effects can be viewed by GPS surveying. They are given through static GPS data static processing, static GPS data kinematic processing, and airborne kinematic GPS data processing. In these cases, the Earth tide effects can be subtracted from the GPS results. The determination...

  12. The use of civilian-type GPS receivers by the military and their vulnerability to jamming

    Directory of Open Access Journals (Sweden)

    Ludwig Combrinck

    2012-05-01

    Full Text Available We considered the impact of external influences on a GPS receiver and how these influences affect the capabilities of civilian-type GPS receivers. A standard commercial radio frequency signal generator and passive GPS antenna were used to test the sensitivity of GPS to intentional jamming; the possible effects of the terrain on the propagation of the jamming signal were also tested. It was found that the high sensitivity of GPS receivers and the low strength level of GPS satellite signals combine to make GPS receivers very vulnerable to intentional jamming or unintentional radio frequency interference. Terrain undulation was used to shield GPS antennas from the direct line-of-sight of the jamming antenna and this indicated that terrain characteristics can be used to mitigate the effects of jamming. These results illuminate the vulnerability of civilian-type GPS receivers to the possibility and the ease of disablement and establish the foundation for future work.

  13. GPS Time Synchronization in School-Network Cosmic Ray Detectors

    Science.gov (United States)

    Berns, H.-G.; Burnett, T. H.; Gran, R.; Wilkes, R. J.

    2004-06-01

    The QuarkNet DAQ card for school-network cosmic ray detectors provides a low-cost alternative to using standard particle and nuclear physics fast pulse electronics modules. The board, which can be produced at a cost of less than $500.00 (USD), produces trigger time and pulse edge time data for 2- to 4-fold coincidence levels via a universal RS232 serial port interface, usable with any PC. Individual detector stations, each consisting of four scintillation counter modules, front-end electronics, and a GPS receiver, produce a stream of data in form of ASCII text strings in identifiable set of formats for different functions. The card includes a low-cost GPS receiver module, which permits time-stamping event triggers to about 50 nanosecond accuracy in UTC between widely separated sites. The technique used for obtaining precise GPS time employs the 1PPS signal, which is not normally available to users of the commercial GPS module. We had the stock model slightly custom-modified to access this signal. The method for deriving time values was adapted from methods developed for the K2K long-baseline neutrino experiment. Performance of the low-cost GPS module used is compared to that of a more expensive unit with known quality.

  14. Ethics support for GPs: what should it look like?

    Science.gov (United States)

    Clark-Grill, Monika

    2016-03-01

    INTRODUCTION Ethics support services for hospital clinicians have become increasingly common globally but not as yet in New Zealand. However, an initiative to change this is gathering momentum. Its slogan 'Clinical ethics is everyone's business' indicates that the aim is to encompass all of health care, not just the hospital sector. General Practitioners (GPs) deal with ethical issues on a daily basis. These issues are often quite different from ethical issues in hospitals. To make future ethics support relevant for primary care, local GPs were interviewed to find out how they might envisage ethics support services that could be useful to them. METHODS A focus group interview with six GPs and semi-structured individual interviews with three GPs were conducted. Questions included how they made decisions on ethical issues at present, what they perceived as obstacles to ethical reflection and decision-making, and what support might be helpful. FINDINGS Three areas of ethics support were considered potentially useful: Formal ethics education during GP training, access to an ethicist for assistance with analysing an ethical issue, and professional guidance with structured ethics conversations in peer groups. CONCLUSION The complex nature of general practice requires GPs to be well educated and supported for handling ethical issues. The findings from this study could serve as input to the development of ethics support services. KEYWORDS General practice; primary care; ethics; support; education.

  15. GPS Technology and Human Psychological Research: A Methodological Proposal

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    Pedro S. A. Wolf

    2010-10-01

    Full Text Available Animal behaviorists have made extensive use of GPS technology since 1991. In contrast, psychological research has made little use of the technology, even though the technology is relatively inexpensive, familiar, and widespread. Hence, its potential for pure and applied psychological research remains untapped. We describe three methods psychologists could apply to individual differences research, clinical research, or spatial use research. In the context of individual differences research, GPS technology permits us to test hypotheses predicting specific relations among patterns of spatial use and individual differences variables. In a clinical context, GPS technology provides outcome measures that may relate to the outcome of interventions designed to treat psychological disorders that, for example, may leave a person homebound (e.g. Agoraphobia, PTSD, TBI. Finally, GPS technology provides natural measures of spatial use. We, for example, used GPS technology to quantify traffic flow and exhibit use at the Arizona Sonora Desert Museum. Interested parties could easily extend this methodology some aspects of urban planning or business usage.DOI: 10.2458/azu_jmmss.v1i1.74

  16. Processing horizontal networks measured by integrated terrestrial and GPS technologies

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    Vincent Jakub

    2003-09-01

    Full Text Available Local horizontal networks in which GPS and terrestrial measurements (TER are done are often established at present. Iin other networks, the previous terrestrial measurements can be completed with quantities from contemporary GPS observations (tunnel nets, mining nets with surface and underground parts and other long-shaped nets.The processing of such heterobeneous (GPS, TER networks whose terrestrial measurements are performed as point coordinate measurements (∆X, ∆Y using (geodetic total stationIn is presented in this paper. In such network structures it is then available:- the values ∆X, ∆Y from TER observations which are transformed in the plane of S-JTSK for adjustement,- the values ∆X, ∆Y in the plane S-JTSK that can be obtained by 3D transformation of WGS84 netpoint coordinates from GPS observations to corresponding coordinates S-JTSK.For common adjusting all the ∆X, ∆Y, some elements of the network geometry (e.g. distances should be measured by both methods (GPS, TER. This approach makes possible an effective homogenisation of both network parts what is equivalent to saying that an expressive influence reduction on local frame realizations of S-JTSK in the whole network can be made.Results of network processing obtained in proposed manner are acceptable in general and they are equivalent (accuracy, reliability to results of another processing methods.

  17. Design about position and display of GPS based on singlechip

    Directory of Open Access Journals (Sweden)

    WU Dongdong

    2016-02-01

    Full Text Available GPS is used in ships,vehicles,aircraft and other moving objects.GPS also has the important application in vehicle monitoring system.However,with the expansion of the specialized functions of GPS,its high cost makes so many ordinary consumers unbearable.This paper proposes a simple design of GPS based on singlechip.The design Improves the basic utility functions of system and adds the speed and mileage measurement.GPS module uses the differential technology to improve the positioning accuracy.Therefore,the navigation device is compact,easy to carry and of high precision positioning.Through getting the data of 3D coordinates from the observation point and the factor of position accuracy,the average of which is less than five,indicating that the position accuracy can be improved by differential technology to achieve the desired range.At last,the feasibility of this design is verified through the current data tested in the outdoors.

  18. GPS water level measurements for Indonesia's Tsunami Early Warning System

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    T. Schöne

    2011-03-01

    Full Text Available On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements.

    The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS (Rudloff et al., 2009 combines GPS technology and ocean bottom pressure (OBP measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information.

    The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.

  19. USO DE RECEPTORES GPS DE 100 HZ NA DETECÇÃO DE DEFLEXÕES VERTICAIS MILIMÉTRICAS DE PONTES DE CONCRETO DE PEQUENO PORTE

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    ANA PAULA CAMARGO LAROCCA

    Full Text Available As últimas quatro décadas foram importantes para o desenvolvimento da malha rodoviária brasileira. O país recebeu incentivos financeiros para a sua expansão e diversas soluções estruturais para pontes e viadutos foram criadas. Em paralelo a este desenvolvimento, houve nos últimos anos um crescimento significativo dessas estruturas em estágio avançado de deterioração devido à ausência de programas de manutenção preventiva. Dessa maneira, este trabalho propõe o uso de receptores GPS num plano de monitoramento de curta duração para acompanhar o comportamento estrutural de uma ponte rodoviária curva de concreto armado já em serviço. E apresenta os primeiros resultados da pesquisa com a portadora L1 do sistema GPS e dados gravados com taxa de 100 Hz, no monitoramento do vão central de ponte de concreto de pequeno porte situada sobre o Rio Jaguari, na cidade de Extrema, divisa entre os Estados de Minas Gerais e São Paulo. O desafio reside no fato de que estruturas como estas - pontes de concreto de pequeno e médio porte - respondem pela grande maioria das obras de arte da malha rodoviária brasileira e por serem estruturas rígidas, apresentam deflexões verticais pequenas, de até 5mm. O experimento foi realizado por meio de sessões de observações com receptores GPS sobre a ponte, no vão instrumentado por equipamentos convencionais para posterior confrontação de resultados entre os receptores GPS e os métodos clássicos de monitoramento. A ferramenta de filtragem Continuos Wavelet Transform (CWT foi utilizada para analisar as frequências de resposta da ponte a partir dos resíduos da dupla diferença de fase da portadora L1. A análise do espectro de energia da CWT gerado a partir dos dados coletados com os receptores GPS indicou alta concentração de energia nas mesmas faixas de frequência - de resposta do tabuleiro da ponte - apontadas pela Modelagem por Elementos Finitos e pela prova de carga dinâmica.

  20. Global GPS Ionospheric Modelling Using Spherical Harmonic Expansion Approach

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    Byung-Kyu Choi

    2010-12-01

    Full Text Available In this study, we developed a global ionosphere model based on measurements from a worldwide network of global positioning system (GPS. The total number of the international GPS reference stations for development of ionospheric model is about 100 and the spherical harmonic expansion approach as a mathematical method was used. In order to produce the ionospheric total electron content (TEC based on grid form, we defined spatial resolution of 2.0 degree and 5.0 degree in latitude and longitude, respectively. Two-dimensional TEC maps were constructed within the interval of one hour, and have a high temporal resolution compared to global ionosphere maps which are produced by several analysis centers. As a result, we could detect the sudden increase of TEC by processing GPS observables on 29 October, 2003 when the massive solar flare took place.

  1. How GPs implement clinical guidelines in everyday clinical practice

    DEFF Research Database (Denmark)

    Videbæk Le, Jette; Hansen, Helle P; Riisgaard, Helle

    2015-01-01

    BACKGROUND: Clinical guidelines are considered to be essential for improving quality and safety of health care. However, interventions to promote implementation of guidelines have demonstrated only partial effectiveness and the reasons for this apparent failure are not yet fully understood....... OBJECTIVE: To investigate how GPs implement clinical guidelines in everyday clinical practice and how implementation approaches differ between practices. METHODS: Individual semi-structured open-ended interviews with seven GPs who were purposefully sampled with regard to gender, age and practice form....... Interviews were recorded, transcribed verbatim and then analysed using systematic text condensation. RESULTS: Analysis of the interviews revealed three different approaches to the implementation of guidelines in clinical practice. In some practices the GPs prioritized time and resources on collective...

  2. High accuracy autonomous navigation using the global positioning system (GPS)

    Science.gov (United States)

    Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul

    1997-01-01

    The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.

  3. What keeps Melbourne GPs satisfied in their jobs?

    Science.gov (United States)

    Walker, Kate Anne; Pirotta, Marie

    2007-10-01

    Workforce shortages make it important to promote job satisfaction and career longevity in general practitioners. We aimed to investigate strategies that maintain and improve Melbourne (Victoria) GP job satisfaction. A postal survey of a random selection of The Royal Australian College of General Practitioners vocationally recognised GPs (N=860). Open ended answers were coded according to themes and compared between genders. Thirty-eight percent of surveyed GPs responded. The mean satisfaction score was 50 out of 70 (SD 9). Women GPs were more satisfied than men with life-work balance (pwork and intellectual stimulation. Strategies to improve GP satisfaction were increased pay, reduced paperwork, and improved administrative systems. General practitioners were satisfied with their jobs due to the intrinsic qualities of their work and workplace. Decreasing the administrative burden, increasing remuneration and improving practice supports may improve metropolitan GP job satisfaction.

  4. Accurate Localization of Communicant Vehicles using GPS and Vision Systems

    Directory of Open Access Journals (Sweden)

    Georges CHALLITA

    2009-07-01

    Full Text Available The new generation of ADAS systems based on cooperation between vehicles can offer serious perspectives to the road security. The inter-vehicle cooperation is made possible thanks to the revolution in the wireless mobile ad hoc network. In this paper, we will develop a system that will minimize the imprecision of the GPS used to car tracking, based on the data given by the GPS which means the coordinates and speed in addition to the use of the vision data that will be collected from the loading system in the vehicle (camera and processor. Localization information can be exchanged between the vehicles through a wireless communication device. The creation of the system must adopt the Monte Carlo Method or what we call a particle filter for the treatment of the GPS data and vision data. An experimental study of this system is performed on our fleet of experimental communicating vehicles.

  5. Mw 8.5 BENGKULU EARTHQUAKES FROM CONTINUOUS GPS DATA

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    W. A. W. Aris

    2016-09-01

    Full Text Available The Mw 8.5 Bengkulu earthquake of 30 September 2007 and the Mw8.6 28 March 2005 are considered amongst large earthquake ever recorded in Southeast Asia. The impact into tectonic deformation was recorded by a network of Global Positioning System (GPS Continuously Operating Reference Station (CORS within southern of Sumatra and west-coast of Peninsular Malaysia. The GPS data from the GPS CORS network has been deployed to investigate the characteristic of postseismic deformation due to the earthquakes. Analytical logarithmic and exponential function was applied to investigate the deformation decay period of postseismic deformation. This investigation provides a preliminary insight into postseismic cycle along the Sumatra subduction zone in particular and on the dynamics Peninsular Malaysia in general.

  6. GPs' negotiation strategies regarding sick leave for subjective health complaints

    DEFF Research Database (Denmark)

    Nilsen, Stein Tore; Malterud, Kirsti; Werner, Erik L.

    2015-01-01

    Objectives: To explore general practitioners ’(GPs’) specific negotiation strategies regarding sick-leave issues with patientssuffering from subjective health complaints. Design: Focus-group study. Setting: Nine focus-group interviews in three citiesin different regions of Norway. Participants: 48...... GPs (31 men, 17 women; age 32–65), participating in a course dealing with diagnostic practice and assessment of sickness certifi cates related to patients with subjective health complaints. Results: TheGPs identified some specific strategies that they claimed to apply when dealing with the question...... to sick leave. Conclusions and implications: GPs seem to have a conscious approach to negotiations of sickness certification, as they report applying specific strategies to limit the duration of sick leave due to subjective health complaints. This give-and-take way of handling sick leave negotiations has...

  7. Automatic Road Centerline Extraction from Imagery Using Road GPS Data

    Directory of Open Access Journals (Sweden)

    Chuqing Cao

    2014-09-01

    Full Text Available Road centerline extraction from imagery constitutes a key element in numerous geospatial applications, which has been addressed through a variety of approaches. However, most of the existing methods are not capable of dealing with challenges such as different road shapes, complex scenes, and variable resolutions. This paper presents a novel method for road centerline extraction from imagery in a fully automatic approach that addresses the aforementioned challenges by exploiting road GPS data. The proposed method combines road color feature with road GPS data to detect road centerline seed points. After global alignment of road GPS data, a novel road centerline extraction algorithm is developed to extract each individual road centerline in local regions. Through road connection, road centerline network is generated as the final output. Extensive experiments demonstrate that our proposed method can rapidly and accurately extract road centerline from remotely sensed imagery.

  8. Reduction Vehicle Speed Using GPS Android Smart Phone Programming

    Directory of Open Access Journals (Sweden)

    Sameer Sami Hassan

    2017-07-01

    Full Text Available Today the new generation of smart phone such as Samsung galaxy, Sony, Motorola, HTC is used to build smart applications that made the human life more comfortable and safe. The Android open source operating system with java programming language can be used to develop such applications. In this paper a new software application has been developed using Samsung, galaxy note smart phone to control the speed of vehicle using GPS and Android programming for such smart phone. By collecting the speed and location information from Global Position System (GPS receiver and using the global map application programming interface to determine the location nearby university, school and hospital in Baghdad city. The application will be check the speed of vehicle in zone of school, hospital and university using GPS information. If the speed over the limit the application produce sound alarm to reduce the speed to set up limit.

  9. GPS-based tracking system for TOPEX orbit determination

    Science.gov (United States)

    Melbourne, W. G.

    1984-01-01

    A tracking system concept is discussed that is based on the utilization of the constellation of Navstar satellites in the Global Positioning System (GPS). The concept involves simultaneous and continuous metric tracking of the signals from all visible Navstar satellites by approximately six globally distributed ground terminals and by the TOPEX spacecraft at 1300-km altitude. Error studies indicate that this system could be capable of obtaining decimeter position accuracies and, most importantly, around 5 cm in the radial component which is key to exploiting the full accuracy potential of the altimetric measurements for ocean topography. Topics covered include: background of the GPS, the precision mode for utilization of the system, past JPL research for using the GPS in precision applications, the present tracking system concept for high accuracy satellite positioning, and results from a proof-of-concept demonstration.

  10. Future potential country doctor: the perspectives of German GPs.

    Science.gov (United States)

    Natanzon, Iris; Szecsenyi, Joachim; Ose, Dominik; Joos, Stefanie

    2010-01-01

    There is a shortage of general practitioners (GPs) in many countries, especially in rural areas. There are several reasons for this shortage. Over the last decade, fewer medical students in Germany have decided to work in patient care, even fewer in general practice and fewer still in general practice in rural areas. The aim of this study was to explore the 'pros and cons' of GPs' work in rural areas and to identify from GPs' perspective possible measures for counteracting future GP shortages. Within a qualitative approach, 16 semi-structured interviews were conducted with GPs. Data analysis was carried out using qualitative content analysis. The results were categorized into three main inductively-derived categories: personal, professional and regional/structural level. A higher level of self-confidence and a higher 'feel-good' factor due to GPs originating from rural areas were positive aspects at the personal level. Regarding the professional level, a low level of competition and varied work made a GP's profession attractive in rural areas. Negative aspects were mostly apparent at the regional/structural level, such a low earnings and few leisure facilities. Measures to counter the lack of GPs in rural areas were explored on all three levels: on the personal level, more optimism and resulting satisfaction on the part of doctors in rural areas could be improved by enhancing the benefits of being a doctor in a rural area. Regarding the professional level, more group practices are required to make working as a GP in a rural area more attractive. At a regional/structural level, young physicians who originate from rural areas should be recruited to work in rural areas. Financial incentives are regarded as not sufficient to attract enough young physicians to open practices in rural areas. Future action will be required at the personal, professional and regional/structural levels. The origin of medical students (urban or rural) should be considered a relevant

  11. Integrated INS/GPS Navigation from a Popular Perspective

    Science.gov (United States)

    Omerbashich, Mensur

    2002-01-01

    Inertial navigation, blended with other navigation aids, Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relatively new concepts based upon using Differential GPS (DGPS) blended with Inertial (and visual) Navigation Sensors (INS) offer the possibility of low cost, autonomous aircraft landing. The FAA has decided to implement the system in a sophisticated form as a new standard navigation tool during this decade. There have been a number of new inertial sensor concepts in the recent past that emphasize increased accuracy of INS/GPS versus INS and reliability of navigation, as well as lower size and weight, and higher power, fault tolerance, and long life. The principles of GPS are not discussed; rather the attention is directed towards general concepts and comparative advantages. A short introduction to the problems faced in kinematics is presented. The intention is to relate the basic principles of kinematics to probably the most used navigation method in the future-INS/GPS. An example of the airborne INS is presented, with emphasis on how it works. The discussion of the error types and sources in navigation, and of the role of filters in optimal estimation of the errors then follows. The main question this paper is trying to answer is 'What are the benefits of the integration of INS and GPS and how is this, navigation concept of the future achieved in reality?' The main goal is to communicate the idea about what stands behind a modern navigation method.

  12. GPR and GPS data integration: examples of application in Antarctica

    Directory of Open Access Journals (Sweden)

    S. Gandolfi

    2001-06-01

    Full Text Available Ground Penetrating Radar (GPR and Global Positioning System (GPS techniques were employed in snow accumulation studies during the Italian leg of the International Trans-Antarctic Scientific Expedition (ITASE. The acquired data were useful both for glaciological and climatological studies. This paper presents some results obtained by GPR and GPS data integration employed to determine accumulation/ablation processes along the profile of the traverse that show how the snow-sublayer thickness can vary quickly in just a few kilometres. Some examples of data integration employed in detection and characterisation of buried crevasses are also presented.

  13. The Aalborg Survey / Part 2 - GPS Based Survey

    DEFF Research Database (Denmark)

    Harder, Henrik; Reiter, Ida Maria; Christensen, Cecilie Breinholm

    , the GPS based data are supplemented with an attractivity analysis among the 169 respondents. The resulting data are presented in maps in three scales that illustrate the respondents’ use of Aalborg’s urban spaces with regards to the respondent’s movements in time and space. By further coupling the GPS...... data with data on the single respondent’s gender, age, address, activities, mode of transport, use of money etc. it is possible to gain a more detailed knowledge of young people’s use of urban spaces in Aalborg....

  14. Mesure GPS sur le circuit du LIER à Lyon

    OpenAIRE

    GIRARD, PL; MARAIS, J

    2006-01-01

    Depuis quelques années le guidage immatériel pour les autobus est à l'ordre du jour et la localisation est une des contraintes à son développement. Pour subvenir à ces besoins la solution GPS est envisagée. Cette technologie en devenir comporte énormément d'avantage notamment en terme coût et de maintenance. L'expérimentation faite à Lyon met en évidence les performances maximales pouvant être obtenu en utilisant le GPS. RAPPORT DE CONTRAT

  15. Tectonic Model of Bali Island Inferred from GPS Data

    OpenAIRE

    Cecep Sulaeman; Sri Hidayati; Amalfi Omang; Imam Catur Priambodo

    2018-01-01

    DOI: 10.17014/ijog.5.1.81-91Seven periods of GPS campaign have been conducted for three years since March 2013 - October 2015 on fourteen GPS sites across Bali Island. The GAMIT/GLOBK 10.6 version was used to compute data with respect for thirteen reference sites of International Terrestrial Reference Frame (ITRF) 2008 surrounding Bali. The result shows that horizontal displacement varies between 1.93 and 22.53 mm/yr dominantly northeastward. Vertical displacement ranges at -184.34 to 33.79 m...

  16. Autonomous GPS/INS navigation experiment for Space Transfer Vehicle

    Science.gov (United States)

    Upadhyay, Triveni N.; Cotterill, Stephen; Deaton, A. W.

    1993-01-01

    An experiment to validate the concept of developing an autonomous integrated spacecraft navigation system using on board Global Positioning System (GPS) and Inertial Navigation System (INS) measurements is described. The feasibility of integrating GPS measurements with INS measurements to provide a total improvement in spacecraft navigation performance, i.e. improvement in position, velocity and attitude information, was previously demonstrated. An important aspect of this research is the automatic real time reconfiguration capability of the system designed to respond to changes in a spacecraft mission under the control of an expert system.

  17. Compact Disks for GPs - this year - next year?

    Directory of Open Access Journals (Sweden)

    Peter Pritchard

    1995-09-01

    Full Text Available Large databases on compact disk are being published at an increasing rate. Medical CDs are few in number, but some useful ones are available now, and more are on the way. Is this the moment for GPs to invest in CD-ROM technology, or would it pay to wait a bit? Five questions will be addressed. What benefits might GPs get from CDs? What is available now? What CDs are on the way? What hardware and software are needed, at what cost? What is the balance of advantage between publications on CD and paper?

  18. Compact Disks for GPs - this year - next year?

    OpenAIRE

    Peter Pritchard

    1995-01-01

    Large databases on compact disk are being published at an increasing rate. Medical CDs are few in number, but some useful ones are available now, and more are on the way. Is this the moment for GPs to invest in CD-ROM technology, or would it pay to wait a bit? Five questions will be addressed. What benefits might GPs get from CDs? What is available now? What CDs are on the way? What hardware and software are needed, at what cost? What is the balance of advantage between publications on CD and...

  19. Study on index system of GPS interference effect evaluation

    Science.gov (United States)

    Zhang, Kun; Zeng, Fangling; Zhao, Yuan; Zeng, Ruiqi

    2018-05-01

    Satellite navigation interference effect evaluation is the key technology to break through the research of Navigation countermeasure. To evaluate accurately the interference degree and Anti-jamming ability of GPS receiver, this text based on the existing research results of Navigation interference effect evaluation, build the index system of GPS receiver effectiveness evaluation from four levels of signal acquisition, tracking, demodulation and positioning/timing and establish the model for each index. These indexes can accurately and quantitatively describe the interference effect at all levels.

  20. Rail inspection system based on iGPS

    Science.gov (United States)

    Fu, Xiaoyan; Wang, Mulan; Wen, Xiuping

    2018-05-01

    Track parameters include gauge, super elevation, cross level and so on, which could be calculated through the three-dimensional coordinates of the track. The rail inspection system based on iGPS (indoor/infrared GPS) was composed of base station, receiver, rail inspection frame, wireless communication unit, display and control unit and data processing unit. With the continuous movement of the inspection frame, the system could accurately inspect the coordinates of rail; realize the intelligent detection and precision measurement. According to principle of angle intersection measurement, the inspection model was structured, and detection process was given.

  1. The use of GPS at IGN : Geodesy, geophysics, engineering

    Science.gov (United States)

    Boucher, Claude; Willis, Pascal

    The Institut Géographique National has purchased since 1985 four GPS receivers (TR5S from SERCEL, 5 channels, single frequency type). For research and production purpose, a specific software, called GDVS, was then developed. This software is now operational and has been used with success to process several GPS campaigns. Two major campaigns were performed in 1986 : one between France and England and the second one between France and Italy. One of the main topic of these campaigns was to connect tide gauges in the Channel area or in the Mediterranean Sea area, to a global reference frame.

  2. Application and Limitations of GPS Radio Occultation (GPS-RO) Data for Atmospheric Boundary Layer Height Detection over the Arctic.

    Science.gov (United States)

    Ganeshan, M.; Wu, D. L.

    2014-12-01

    Due to recent changes in the Arctic environment, it is important to monitor the atmospheric boundary layer (ABL) properties over the Arctic Ocean, especially to explore the variability in ABL clouds (such as sensitivity and feedback to sea ice loss). For example, radiosonde and satellite observations of the Arctic ABL height (and low-cloud cover) have recently suggested a positive response to sea ice loss during October that may not occur during the melt season (June-September). Owing to its high vertical and spatiotemporal resolution, an independent ABL height detection algorithm using GPS Radio Occultation (GPS-RO) refractivity in the Arctic is explored. Similar GPS-RO algorithms developed previously typically define the level of the most negative moisture gradient as the ABL height. This definition is favorable for subtropical oceans where a stratocumulus-topped ABL is often capped by a layer of sharp moisture lapse rate (coincident with the temperature inversion). The Arctic Ocean is also characterized by stratocumulus cloud cover, however, the specific humidity does not frequently decrease in the ABL capping inversion. The use of GPS-RO refractivity for ABL height retrieval therefore becomes more complex. During winter months (December-February), when the total precipitable water in the troposphere is a minimum, a fairly straightforward algorithm for ABL height retrieval is developed. The applicability and limitations of this method for other seasons (Spring, Summer, Fall) is determined. The seasonal, interannual and spatial variability in the GPS-derived ABL height over the Arctic Ocean, as well as its relation to the underlying surface (ice vs. water), is investigated. The GPS-RO profiles are also explored for the evidence of low-level moisture transport in the cold Arctic environment.

  3. Research in Application of Geodetic GPS Receivers in Time Synchronization

    Science.gov (United States)

    Zhang, Q.; Zhang, P.; Sun, Z.; Wang, F.; Wang, X.

    2018-04-01

    In recent years, with the development of satellite orbit and clock parameters accurately determining technology and the popularity of geodetic GPS receivers, Common-View (CV) which proposed in 1980 by Allan has gained widespread application and achieved higher accuracy time synchronization results. GPS Common View (GPS CV) is the technology that based on multi-channel geodetic GPS receivers located in different place and under the same common-view schedule to receiving same GPS satellite signal at the same time, and then calculating the time difference between respective local receiver time and GPST by weighted theory, we will obtain the difference between above local time of receivers that installed in different station with external atomic clock. Multi-channel geodetic GPS receivers have significant advantages such as higher stability, higher accuracy and more common-view satellites in long baseline time synchronization application over the single-channel geodetic GPS receivers. At present, receiver hardware delay and surrounding environment influence are main error factors that affect the accuracy of GPS common-view result. But most error factors will be suppressed by observation data smoothing and using of observation data from different satellites in multi-channel geodetic GPS receiver. After the SA (Selective Availability) cancellation, using a combination of precise satellite ephemeris, ionospheric-free dual-frequency P-code observations and accurately measuring of receiver hardware delay, we can achieve time synchronization result on the order of nanoseconds (ns). In this paper, 6 days observation data of two IGS core stations with external atomic clock (PTB, USNO distance of two stations about 6000 km) were used to verify the GPS common-view theory. Through GPS observation data analysis, there are at least 2-4 common-view satellites and 5 satellites in a few tracking periods between two stations when the elevation angle is 15°, even there will be at least

  4. RESEARCH IN APPLICATION OF GEODETIC GPS RECEIVERS IN TIME SYNCHRONIZATION

    Directory of Open Access Journals (Sweden)

    Q. Zhang

    2018-04-01

    Full Text Available In recent years, with the development of satellite orbit and clock parameters accurately determining technology and the popularity of geodetic GPS receivers, Common-View (CV which proposed in 1980 by Allan has gained widespread application and achieved higher accuracy time synchronization results. GPS Common View (GPS CV is the technology that based on multi-channel geodetic GPS receivers located in different place and under the same common-view schedule to receiving same GPS satellite signal at the same time, and then calculating the time difference between respective local receiver time and GPST by weighted theory, we will obtain the difference between above local time of receivers that installed in different station with external atomic clock. Multi-channel geodetic GPS receivers have significant advantages such as higher stability, higher accuracy and more common-view satellites in long baseline time synchronization application over the single-channel geodetic GPS receivers. At present, receiver hardware delay and surrounding environment influence are main error factors that affect the accuracy of GPS common-view result. But most error factors will be suppressed by observation data smoothing and using of observation data from different satellites in multi-channel geodetic GPS receiver. After the SA (Selective Availability cancellation, using a combination of precise satellite ephemeris, ionospheric-free dual-frequency P-code observations and accurately measuring of receiver hardware delay, we can achieve time synchronization result on the order of nanoseconds (ns. In this paper, 6 days observation data of two IGS core stations with external atomic clock (PTB, USNO distance of two stations about 6000 km were used to verify the GPS common-view theory. Through GPS observation data analysis, there are at least 2–4 common-view satellites and 5 satellites in a few tracking periods between two stations when the elevation angle is 15°, even

  5. Kinematics with the assistance of smartphones: Measuring data via GPS - Visualizing data with Google Earth

    Science.gov (United States)

    Gabriel, Patrik; Backhaus, Udo

    2013-04-01

    Nearly every smartphone is now GPS capable. The widespread use of GPS navigation has developed alongside less expensive hardware and user-friendly software interfaces, which may help to bring scientific research and teaching closer to real life.

  6. IceBridge GPS L0 Raw Satellite Navigation Data, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge GPS L0 Raw Satellite Navigation Data (IPUTG0) data set contains GPS readings, including latitude, longitude, track, ground speed, off distance,...

  7. WGS 84 Coordinate Validation and Improvement for the NIMA and Air Force GPS Tracking Stations

    National Research Council Canada - National Science Library

    Cunningham, James

    1996-01-01

    Using 10 days of Global Positioning System (GPS) pseudorange and carrier phase data collected in 1995 from 31 stations and 24 Block II/IIA satellites, estimates of GPS clocks, orbits, and tracking station coordinates were generated...

  8. Vähemalt kolm hunti saavad veel GPS-kaelused / Madis Filippov

    Index Scriptorium Estoniae

    Filippov, Madis

    2011-01-01

    Esimene Eesti hunt sai kaela GPS-seadme, mis hakkab edastama teavet looma toitumise ja elupiirkonna kohta, lähiajal on plaanis samasuguse seadme paigaldamine veel vähemalt kolmele hundile. GPS loomadel

  9. Android App Based Vehicle Tracking Using GPS And GSM

    Directory of Open Access Journals (Sweden)

    Jessica Saini

    2017-09-01

    Full Text Available Global Positioning System GPS is used in numerous applications in todays world. A real time vehicle tracking system using the GPS technology is proposed in this paper. The project Android App based Vehicle Tracking Using GSM AND GPRS mainly focuses in tracking the location of the vehicle on which the device has been installed. It will then send the data in the form of latitude and longitude coordinates through SMS on the users mobile where the coordinates will be plotted in the Android app automatically. Initially the GPS installed in the device takes input from the satellite and stores it in the microcontrollers buffer. In order to track the vehicle the mobile user has to call on the SIM number that is registered in the GSM module of the device. Once the call is received the device authenticates the calling number. If authenticated the location of the vehicle is sent to the registered mobile number in the form of SMS. After sending the message the GSM is deactivated and the GPS is activated again. The coordinates of the location received in the SMS can be viewed on the android app. The hardware part described in the paper comprises of GPRS GSM module LCD to view the coordinates ATMega Microcontroller MAX 232 Arduino RS232 and relay.

  10. Implementation of GPS controlled highway construction equipment, phase III.

    Science.gov (United States)

    2009-02-01

    Beginning in 2006, WisDOT and the Construction Material and Support Center (CMSC) at UW-Madison worked : together to develop the specifications and the QA/QC procedures for GPS machine guidance on highway grading : projects. These specifications and ...

  11. Truck Route Choice Modeling using Large Streams of GPS Data

    Science.gov (United States)

    2017-07-31

    The primary goal of this research was to use large streams of truck-GPS data to analyze travel routes (or paths) chosen by freight trucks to travel between different origin and destination (OD) location pairs in metropolitan regions of Florida. Two s...

  12. GPS: Shaping Student Success One Conversation at a Time

    Science.gov (United States)

    Star, Mikhael; Collette, Lanita

    2010-01-01

    Increasing instructor-student interactions and improving support personnel interventions with students positively affects their academic performance, retention, and graduation rates. This article discusses the Grade Performance Status (GPS) which is Northern Arizona University's new online, academic early alert tool for increasing instructor…

  13. Effects of GPS sampling intensity on home range analyses

    Science.gov (United States)

    Jeffrey J. Kolodzinski; Lawrence V. Tannenbaum; David A. Osborn; Mark C. Conner; W. Mark Ford; Karl V. Miller

    2010-01-01

    The two most common methods for determining home ranges, minimum convex polygon (MCP) and kernel analyses, can be affected by sampling intensity. Despite prior research, it remains unclear how high-intensity sampling regimes affect home range estimations. We used datasets from 14 GPS-collared, white-tailed deer (Odocoileus virginianus) to describe...

  14. Jason-1 and Jason-2 POD Using GPS

    Science.gov (United States)

    Melachroinos, Stavros; Lemoine, Frank G.; Zelensky, Nikita P.; Rowlands, David D.; Luthcke, Scott B.; Beckley, Brian D.

    2012-01-01

    The Jason-2 satellite, launched in June 2008, is the latest follow-on to the successful Jason-1 altimetry satellite mission launched in December 7, 2001. Both, Jason-2 and Jason-1 are equipped with a GPS dual-frequency receiver, a laser retroreflector array, and a DORIS receiver for precise orbit determination (POD). A series of dynamic and reduced-dynamic Jason-2 orbits computed at NASA GSFC, based on GPS-only data and the std0905 standards, have been completed till cy74through cycle 74 using the IGS05 framework. These orbits, now publicly available, have been shown to agree radially at 1 cm RMS with the GSFC std0905 SLR/DORIS orbits and in comparison with orbits produced by JPL, ESA and CNES. In this paper, we describe the implementation of the IGS08 and repro1 framework for the Jason-2 and Jason-1 GPS POD processing with the NASA GSFC GEODYN software. . In our updated GPS POD, ambiguity fixing and updated time variable and static gravity fields. We also evaluate the implementation of non-tidal and degree-1 loading displacement as forward modeling to the tracking stations. Reduced-dynamic versus dynamic orbit differences are used to characterize the remaining force model errors and TRF instability. In particular, we assess their consistency radially and the stability of the altimeter satellite reference frame in the North/South direction as a proxy to assess the consistency of the reference frame.

  15. Variability of GPS Radio Sources at 5 GHz

    Indian Academy of Sciences (India)

    GPS) radio sources at 5 GHz and find that about one-third of them show considerable Inter-Month Variability (IMV), and these IMV phenomena are likely to be caused by interstellar scintillation (ISS). Furthermore, we find that those showing IMV ...

  16. GPS location data enhancement in electronic traffic records.

    Science.gov (United States)

    2013-01-01

    In this project we developed a new GPS-based Geographical Information Exchange : Framework (GIEF) to improve the correctness and accuracy of location data reported on : electronic police forms in Oklahoma. A second major goal was to provide a base le...

  17. Improved Solar-Radiation-Pressure Models for GPS Satellites

    Science.gov (United States)

    Bar-Sever, Yoaz; Kuang, Da

    2006-01-01

    A report describes a series of computational models conceived as an improvement over prior models for determining effects of solar-radiation pressure on orbits of Global Positioning System (GPS) satellites. These models are based on fitting coefficients of Fourier functions of Sun-spacecraft- Earth angles to observed spacecraft orbital motions.

  18. by monitoring microgravity and GPS/GNSS methods

    Indian Academy of Sciences (India)

    Dokuz Eylul University, Department of Geophysical Engineering, Tınaztepe Campus, Buca, Izmir, Turkey. ∗. Corresponding author. e-mail: .... For processing GPS/GNSS data, the software, which is called GAMIT/GLOBK (Herring 2009; .... trend for DEU6, DEU7, DEU8, DEU5, DEU11 measurement points (uplift), stable for ...

  19. An alternative methodology for the mathematical treatment of GPS positioning

    Directory of Open Access Journals (Sweden)

    Aly M. El-naggar

    2011-12-01

    In this paper a simple alternative method is developed to solve the GPS navigation equations directly without linearization and iteration. A practical study was done to evaluate the new model. Performance analysis was conducted using data collected by Trimble 4000SSE dual frequency receiver. The results indicated that the alternative methodology is simple, fast, and accurate as compared to Taylor method.

  20. GPS-based ionospheric tomography with a constrained adaptive ...

    Indian Academy of Sciences (India)

    Gauss weighted function is introduced to constrain the tomography system in the new method. It can resolve the ... the research focus in the fields of space geodesy and ... ment of GNSS such as GPS, Glonass, Galileo and. Compass, as these ...

  1. Ionospheric correction for spaceborne single-frequency GPS based ...

    Indian Academy of Sciences (India)

    The Klobuchar model was used to compute ionospheric delays for the dlft station, and .... dual-frequency GPS receivers; therefore, the iono- ... The mapping function is defined as the ratio of .... eter in the processing of an extended set of single.

  2. Evaluation of EGM2008 by means of GPS Levelling Uganda

    African Journals Online (AJOL)

    Personal

    The global gravity model EGM2008 is evaluated in various regions of ... two so that the computed difference [0.118m] in datum offset for the two states does tell us .... GAMIT is a collection of programs to process GPS phase data to estimate ...

  3. Using GPS-tracking technology for urban design interventions

    NARCIS (Netherlands)

    Van der Spek, S.C.; Van Langelaar, C.M.

    2011-01-01

    The aim of this paper is to express the application of tracking technologies in Urban Design and Planning. Tracking technologies can be used to monitor different user groups in different occasions. Since 2005, TU Delft has explored and developed two types of research using GPS to collect spatio

  4. GPs motivations of prescribing antidepressants and their practical relevance.

    NARCIS (Netherlands)

    Volkers, A.; Jong, A. de; Braspenning, J.C.C.; Bakker, D. de; Dijk, L. van

    2004-01-01

    Background: Insight in the motivations of prescribing antidepressants may contribute to advance the efficiency of the current, large antidepressant prescription rate. Less is known about why general practitioners (GPs) treat patients with antidepressants or not and choose modern SSRIs instead of the

  5. Evaluating the accuracy of GPS-based taxi trajectory records

    NARCIS (Netherlands)

    Zheng, Zhong; Rasouli, Soora; Timmermans, Harry

    2014-01-01

    Taxi data are an underused source of travel information. A handful of research has been concerned with the processing of raw taxi GPS data to minimize random error. The study of methods that systematically detect erroneous data has, however, received less attention. Generally, an origin and a

  6. Detecting Traffic Anomalies in Urban Areas Using Taxi GPS Data

    Directory of Open Access Journals (Sweden)

    Weiming Kuang

    2015-01-01

    Full Text Available Large-scale GPS data contain hidden information and provide us with the opportunity to discover knowledge that may be useful for transportation systems using advanced data mining techniques. In major metropolitan cities, many taxicabs are equipped with GPS devices. Because taxies operate continuously for nearly 24 hours per day, they can be used as reliable sensors for the perceived traffic state. In this paper, the entire city was divided into subregions by roads, and taxi GPS data were transformed into traffic flow data to build a traffic flow matrix. In addition, a highly efficient anomaly detection method was proposed based on wavelet transform and PCA (principal component analysis for detecting anomalous traffic events in urban regions. The traffic anomaly is considered to occur in a subregion when the values of the corresponding indicators deviate significantly from the expected values. This method was evaluated using a GPS dataset that was generated by more than 15,000 taxies over a period of half a year in Harbin, China. The results show that this detection method is effective and efficient.

  7. Cell jammers, GPS jammers, and other jamming devices.

    Science.gov (United States)

    2012-10-15

    We caution consumers that it is against the law to use a cell or GPS jammer or any other type of device that blocks, : jams or interferes with authorized communications, as well as to import, advertise, sell, or ship such a device. The : FCC Enforcem...

  8. GPS-based ionospheric tomography with a constrained adaptive ...

    Indian Academy of Sciences (India)

    According to the continuous smoothness of the variations of ionospheric electron density (IED) among neighbouring voxels, Gauss weighted function is introduced to constrain the tomography system in the new method. It can resolve the dependence on the initial values for those voxels without any GPS rays traversing them ...

  9. Managing the GPS/GIS function in an electric utility

    International Nuclear Information System (INIS)

    Michelsen, M.W. Jr.

    1999-01-01

    A new period of higher significance has arrived for the GPS/GIS function at electric utilities such that to a degree never seen before, utility managers are looking to their GIS programs, filled with increasingly accurate data collected by GPS technology, before making many decisions. With this capability comes an expectation for GPS/GIS professionals to provide higher levels of planning and management of their data collection process. At Duke Power in Charlotte, North Carolina, managers rely on GPS mapping to fill their data collection equipment needs. When the city of Charlotte requested a more detailed billing system, Duke Power co-sponsored the street lighting inventory project, a comprehensive program implemented to fully account for street lighting facilities within the billing area. One of the key projects to be kept in mind was the creation of a common data base viewable by GIS from which a bill could be created and as well reveal data. A billing calculation routine can be run against the data base to generate a bill or use MapInfo to see a graphical picture. Prior to the creation of this data base capability, the difference between the data base as a display tool and billing system was a potential source of discrepancy, which is eliminated now. Creating the data base allows more than just creating a bill for the city, it allows Duke Power to work better with the city by improving its billing accountability and provides better service as well

  10. GPS surveying method applied to terminal area navigation flight experiments

    Energy Technology Data Exchange (ETDEWEB)

    Murata, M; Shingu, H; Satsushima, K; Tsuji, T; Ishikawa, K; Miyazawa, Y; Uchida, T [National Aerospace Laboratory, Tokyo (Japan)

    1993-03-01

    With an objective of evaluating accuracy of new landing and navigation systems such as microwave landing guidance system and global positioning satellite (GPS) system, flight experiments are being carried out using experimental aircraft. This aircraft mounts a GPS and evaluates its accuracy by comparing the standard orbits spotted by a Kalman filter from the laser tracing data on the aircraft with the navigation results. The GPS outputs position and speed information from an earth-centered-earth-fixed system called the World Geodetic System, 1984 (WGS84). However, in order to compare the navigation results with output from a reference orbit sensor or other navigation sensor, it is necessary to structure a high-precision reference coordinates system based on the WGS84. A method that applies the GPS phase interference measurement for this problem was proposed, and used actually in analyzing a flight experiment data. As referred to a case of the method having been applied to evaluating an independent navigation accuracy, the method was verified sufficiently effective and reliable not only in navigation method analysis, but also in the aspect of navigational operations. 12 refs., 10 figs., 5 tabs.

  11. Video-Aided GPS/INS Positioning and Attitude Determination

    National Research Council Canada - National Science Library

    Brown, Alison; Silva, Randy

    2006-01-01

    ... precise positioning and attitude information to be maintained, even during periods of extended GPS dropouts. This relies on information extracted from the video images of reference points and features to continue to update the inertial navigation solution. In this paper, the principles of the video-update method aredescribed.

  12. A generalized development model for testing GPS user equipment

    Science.gov (United States)

    Hemesath, N.

    1978-01-01

    The generalized development model (GDM) program, which was intended to establish how well GPS user equipment can perform under a combination of jamming and dynamics, is described. The systems design and the characteristics of the GDM are discussed. The performance aspects of the GDM are listed and the application of the GDM to civil aviation is examined.

  13. Asthma prescription patterns for children: can GPs do better?

    NARCIS (Netherlands)

    Uijen, J.H.J.M.; Wouden, J.C. van der; Schellevis, F.G.; Willemsen, S.P.; Suijlekom-Smit, L.W.A. van; Bindels, P.J.E.

    2011-01-01

    Background: Assessing prescription patterns of asthma medication for children is helpful to optimize prescribing by general practitioners (GPs). The aim was to explore prescription patterns in children with physician-diagnosed asthma and its determinants in general practice. Methods: We used the

  14. Evaluation of Mobile Phone Interference With Aircraft GPS Navigation Systems

    Science.gov (United States)

    Pace, Scott; Oria, A. J.; Guckian, Paul; Nguyen, Truong X.

    2004-01-01

    This report compiles and analyzes tests that were conducted to measure cell phone spurious emissions in the Global Positioning System (GPS) radio frequency band that could affect the navigation system of an aircraft. The cell phone in question had, as reported to the FAA (Federal Aviation Administration), caused interference to several GPS receivers on-board a small single engine aircraft despite being compliant with data filed at the time with the FCC by the manufacturer. NASA (National Aeronautics and Space Administration) and industry tests show that while there is an emission in the 1575 MHz GPS band due to a specific combination of amplifier output impedance and load impedance that induces instability in the power amplifier, these spurious emissions (i.e., not the intentional transmit signal) are similar to those measured on non-intentionally transmitting devices such as, for example, laptop computers. Additional testing on a wide sample of different commercial cell phones did not result in any emission in the 1575 MHz GPS Band above the noise floor of the measurement receiver.

  15. A different approach to the analysis of GPS scintillations data

    International Nuclear Information System (INIS)

    Forte, B.; Radicella, S.M.; Ezquer, R.G.

    2001-09-01

    Amplitude scintillations data from GPS have been analyzed. The objective is to estimate the impact of ionospheric scintillations at Satellite-Based Augmentation System (SBAS) Ranging and Integrity Monitoring Station (RIMS) level and at GPS user level. For this purpose a new approach to the problem has been considered. Data have been studied from the point of view of the impact of scintillations on the calculation of VTEC at pierce points and ionospheric grid points. An ionospheric grid of 5 deg. by 5 deg. surface squares has been assumed. From geometrical considerations and taking into account the basic principle to compute VTEC at grid points, with the data analyzed it is shown that very seldom scintillations can affect the calculation of a grid point VTEC. Data from all the RIMS and for the entire GPS satellites network must be analyzed simultaneously to describe a realistic scenario for the impact of scintillations on SBAS. Finally, GPS scintillation data have been analyzed at user level: service availability problems have been encountered. (author)

  16. Development and Validation of the Game Perception Scale (GPS)

    Science.gov (United States)

    Vandercruysse, Sylke; Vandewaetere, Mieke; Maertens, Marie; ter Vrugte, Judith; Wouters, Pieter; de Jong, Ton; van Oostendorp, Herre; Elen, Jan

    2015-01-01

    Despite the pervasiveness of perception and considerable impact of perception on the use of ICT for educational purposes, there is a surprising paucity of perception assessment instruments. The present proposal expands on this through the development and initial validation of the Game Perception Scale (GPS). Based on perception literature,…

  17. A GPS measurement system for precise satellite tracking and geodesy

    Science.gov (United States)

    Yunck, T. P.; Wu, S.-C.; Lichten, S. M.

    1985-01-01

    NASA is pursuing two key applications of differential positioning with the Global Positioning System (GPS): sub-decimeter tracking of earth satellites and few-centimeter determination of ground-fixed baselines. Key requirements of the two applications include the use of dual-frequency carrier phase data, multiple ground receivers to serve as reference points, simultaneous solution for use position and GPS orbits, and calibration of atmospheric delays using water vapor radiometers. Sub-decimeter tracking will be first demonstrated on the TOPEX oceanographic satellite to be launched in 1991. A GPS flight receiver together with at least six ground receivers will acquire delta range data from the GPS carriers for non-real-time analysis. Altitude accuracies of 5 to 10 cm are expected. For baseline measurements, efforts will be made to obtain precise differential pseudorange by resolving the cycle ambiguity in differential carrier phase. This could lead to accuracies of 2 or 3 cm over a few thousand kilometers. To achieve this, a high-performance receiver is being developed, along with improved calibration and data processing techniques. Demonstrations may begin in 1986.

  18. GPS/MEMS IMU/Microprocessor Board for Navigation

    Science.gov (United States)

    Gender, Thomas K.; Chow, James; Ott, William E.

    2009-01-01

    A miniaturized instrumentation package comprising a (1) Global Positioning System (GPS) receiver, (2) an inertial measurement unit (IMU) consisting largely of surface-micromachined sensors of the microelectromechanical systems (MEMS) type, and (3) a microprocessor, all residing on a single circuit board, is part of the navigation system of a compact robotic spacecraft intended to be released from a larger spacecraft [e.g., the International Space Station (ISS)] for exterior visual inspection of the larger spacecraft. Variants of the package may also be useful in terrestrial collision-detection and -avoidance applications. The navigation solution obtained by integrating the IMU outputs is fed back to a correlator in the GPS receiver to aid in tracking GPS signals. The raw GPS and IMU data are blended in a Kalman filter to obtain an optimal navigation solution, which can be supplemented by range and velocity data obtained by use of (l) a stereoscopic pair of electronic cameras aboard the robotic spacecraft and/or (2) a laser dynamic range imager aboard the ISS. The novelty of the package lies mostly in those aspects of the design of the MEMS IMU that pertain to controlling mechanical resonances and stabilizing scale factors and biases.

  19. Danish GPs' perception of disease risk and benefit of prevention

    DEFF Research Database (Denmark)

    Nexøe, Jørgen; Gyrd-Hansen, Dorte; Kragstrup, Jakob

    2002-01-01

    risk reduction. RESULTS: The GPs' attitude towards recommending medical treatment was dependent on the phrasing of risk reductions. Seventy-two per cent of doctors who received all information on risk reductions would definitely or probably recommend medication, while 91% would recommend medication...... to take into account all available measures of risk reductions....

  20. Remote landslide mapping using a laser rangefinder binocular and GPS

    Directory of Open Access Journals (Sweden)

    M. Santangelo

    2010-12-01

    Full Text Available We tested a high-quality laser rangefinder binocular coupled with a GPS receiver connected to a Tablet PC running dedicated software to help recognize and map in the field recent rainfall-induced landslides. The system was tested in the period between March and April 2010, in the Monte Castello di Vibio area, Umbria, Central Italy. To test the equipment, we measured thirteen slope failures that were mapped previously during a visual reconnaissance field campaign conducted in February and March 2010. For reference, four slope failures were also mapped by walking the GPS receiver along the landslide perimeter. Comparison of the different mappings revealed that the geographical information obtained remotely for each landslide by the rangefinder binocular and GPS was comparable to the information obtained by walking the GPS around the landslide perimeter, and was superior to the information obtained through the visual reconnaissance mapping. Although our tests were not exhaustive, we maintain that the system is effective to map recent rainfall induced landslides in the field, and we foresee the possibility of using the same (or similar system to map landslides, and other geomorphological features, in other areas.

  1. Utilization of GPS Tropospheric Delays for Climate Research

    International Nuclear Information System (INIS)

    Suparta, Wayan

    2017-01-01

    The tropospheric delay is one of the main error sources in Global Positioning Systems (GPS) and its impact plays a crucial role in near real-time weather forecasting. Accessibility and accurate estimation of this parameter are essential for weather and climate research. Advances in GPS application has allowed the measurements of zenith tropospheric delay (ZTD) in all weather conditions and on a global scale with fine temporal and spatial resolution. In addition to the rapid advancement of GPS technology and informatics and the development of research in the field of Earth and Planetary Sciences, the GPS data has been available free of charge. Now only required sophisticated processing techniques but user friendly. On the other hand, the ZTD parameter obtained from the models or measurements needs to be converted into precipitable water vapor (PWV) to make it more useful as a component of weather forecasting and analysis atmospheric hazards such as tropical storms, flash floods, landslide, pollution, and earthquake as well as for climate change studies. This paper addresses the determination of ZTD as a signal error or delay source during the propagation from the satellite to a receiver on the ground and is a key driving force behind the atmospheric events. Some results in terms of ZTD and PWV will be highlighted in this paper. (paper)

  2. Kalman filter implementation for small satellites using constraint GPS data

    Science.gov (United States)

    Wesam, Elmahy M.; Zhang, Xiang; Lu, Zhengliang; Liao, Wenhe

    2017-06-01

    Due to the increased need for autonomy, an Extended Kalman Filter (EKF) has been designed to autonomously estimate the orbit using GPS data. A propagation step models the satellite dynamics as a two body with J2 (second zonal effect) perturbations being suitable for orbits in altitudes higher than 600 km. An onboard GPS receiver provides continuous measurement inputs. The continuity of measurements decreases the errors of the orbit determination algorithm. Power restrictions are imposed on small satellites in general and nanosatellites in particular. In cubesats, the GPS is forced to be shut down most of the mission’s life time. GPS is turned on when experiments like atmospheric ones are carried out and meter level accuracy for positioning is required. This accuracy can’t be obtained by other autonomous sensors like magnetometer and sun sensor as they provide kilometer level accuracy. Through simulation using Matlab and satellite tool kit (STK) the position accuracy is analyzed after imposing constrained conditions suitable for small satellites and a very tight one suitable for nanosatellite missions.

  3. Communication plan of GPS monitoring system based on the Internet

    Science.gov (United States)

    Xing, Xiangpeng; Liu, Zhenan; Bao, Yuanlu

    2005-11-01

    In GPS monitoring system, wireless communications network is necessary to keep base station in contact with mobile stations. Public communications network and personal communications network can't work well all the time. In this article, an economical communications network that can be competent for communication of GPS monitoring system is introduced. Personal communications network is used in this GPS monitoring system. In order to enlarge the coverage area and to expand the capacity of the personal communications network, the concept of cellular radio system is introduced. Because only the non-adjacent cells can use the same frequency channel, handoff of mobile station is extremely important when it goes in another cell. The mobile station of the system will know its own longitude and latitude by receiving data from GPS satellites all the time, so it can change its working frequency channel according to its position. Internet, instead of personal communication cable, is used to connect the base stations. So the communications network has the advantage of public communications network and personal one.

  4. Seasonal and circadian biases in bird tracking with solar GPS-tags

    OpenAIRE

    Silva, Rafa; Afán, Isabel; Gil, Juan A.; Bustamante, Javier

    2017-01-01

    Global Positioning System (GPS) tags are nowadays widely used in wildlife tracking. This geolocation technique can suffer from fix loss biases due to poor satellite GPS geometry, that result in tracking data gaps leading to wrong research conclusions. In addition, new solar-powered GPS tags deployed on birds can suffer from a new "battery drain bias" currently ignored in movement ecology analyses. We use a GPS tracking dataset of bearded vultures (Gypaetus barbatus), tracked for several years...

  5. The application of GPS time information in the telemetry ground station

    International Nuclear Information System (INIS)

    Zhang Songtao; Zhang Yusong; Sun Xiurui

    2001-01-01

    GPS time information is a kind of practicable information resource that can be shared all over the world. Now it is the most accurate wireless time information. The major of this paper is the application information of GPS time information in telemetry. The main point introduces how to make use of the GPS time information to produce GPS-IRIG-B time code for proving ground and how to send time information to related equipment in telemetry ground station

  6. [Quality of life of women GPs in Auvergne].

    Science.gov (United States)

    Mathonnat, Marie Dolorès; Filloux, Isabelle; Tanguy, Gilles; Eschalier, Bénédicte; Pereira, Bruno; Vorilhon, Philippe

    2013-10-01

    The medical profession is feminising. In parallel, the importance of quality of life (QOL) must be addressed. Family practice needs personal investment and availability. This profession can have repercussions on womens' QOL. The objective of the study was to compare female GPs QOL to other women with the comparable socioprofessional status. The secondary objective was to study the influence of factors, such as workplace and work methods. Comparative cross-sectional study. A self-assessed questionnaire, sent by post to 394 female general practitioners in Auvergne, each was asked to recruit one woman (non-GP), with similar age and socioprofessional status. A total of 148 female GPs (37.6%) and 122 non-GPs responded. The global score of QOL was lower in the GP group, noticeably showing a poorer QOL in the relational and material areas. The professional QOL was similar between the 2 groups. The study did not find a significant difference concerning the QOL in its physical and psychological dimensions. The main negative factors influencing the QOL were: age; isolation of the occupation; living alone; and liberal occupation. Working in a rural area did not influence the QOL. The profession of GPs remains demanding, and the female GP feels a poorer QOL. Nevertheless, they seem to like their job and they feel fulfilled. The uneasiness comes essentially from the lack of free time, and from low financial income. Working in association seems to be a first step to improve the QOL of female GPs. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  7. Fast-Acquisition/Weak-Signal-Tracking GPS Receiver for HEO

    Science.gov (United States)

    Wintemitz, Luke; Boegner, Greg; Sirotzky, Steve

    2004-01-01

    A report discusses the technical background and design of the Navigator Global Positioning System (GPS) receiver -- . a radiation-hardened receiver intended for use aboard spacecraft. Navigator is capable of weak signal acquisition and tracking as well as much faster acquisition of strong or weak signals with no a priori knowledge or external aiding. Weak-signal acquisition and tracking enables GPS use in high Earth orbits (HEO), and fast acquisition allows for the receiver to remain without power until needed in any orbit. Signal acquisition and signal tracking are, respectively, the processes of finding and demodulating a signal. Acquisition is the more computationally difficult process. Previous GPS receivers employ the method of sequentially searching the two-dimensional signal parameter space (code phase and Doppler). Navigator exploits properties of the Fourier transform in a massively parallel search for the GPS signal. This method results in far faster acquisition times [in the lab, 12 GPS satellites have been acquired with no a priori knowledge in a Low-Earth-Orbit (LEO) scenario in less than one second]. Modeling has shown that Navigator will be capable of acquiring signals down to 25 dB-Hz, appropriate for HEO missions. Navigator is built using the radiation-hardened ColdFire microprocessor and housing the most computationally intense functions in dedicated field-programmable gate arrays. The high performance of the algorithm and of the receiver as a whole are made possible by optimizing computational efficiency and carefully weighing tradeoffs among the sampling rate, data format, and data-path bit width.

  8. 78 FR 13396 - 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Science.gov (United States)

    2013-02-27

    ... 159, Global Positioning Systems (GPS) AGENCY: Federal Aviation Administration (FAA), U.S. Department... 159, Global Positioning Systems (GPS) SUMMARY: The FAA is issuing this notice to advise the public of the eighty-ninth meeting of the RTCA Special Committee 159, Global Positioning Systems (GPS). DATES...

  9. 75 FR 2581 - Eighty-First Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2010-01-15

    ... Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is... System (GPS). DATES: The meeting will be held February 2-5, 2010, from 9 a.m. to 4:30 p.m. (unless stated...

  10. 76 FR 27744 - Eighty-Fifth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2011-05-12

    ... Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is... System (GPS). DATES: The meeting will be held May 26, 2011, from 9 a.m. to 11:45 a.m. ADDRESSES: The...

  11. 77 FR 25150 - GPS Satellite Simulator Working Group; Notice of Meeting

    Science.gov (United States)

    2012-04-27

    ... DEPARTMENT OF DEFENSE Department of the Air Force GPS Satellite Simulator Working Group; Notice of Meeting AGENCY: The United States Air Force, DoD. ACTION: Amending GPS Simulator Working group Meeting Notice. SUMMARY: We are requesting to amend the date of the GPS Simulator Working group meeting notice...

  12. 76 FR 67019 - Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2011-10-28

    ... Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration (FAA), U.S... System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of a meeting of RTCA Special Committee 159: Global Positioning System (GPS) 87th meeting. DATES: The meeting will be held November 14-18...

  13. 76 FR 33022 - Eighty-Sixth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2011-06-07

    ... Committee 159: Global Positioning System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning System (GPS). SUMMARY: The FAA is... System (GPS). DATES: The meeting will be held June 13-17, 2011, from 9 a.m. to 4:30 p.m. ADDRESSES: The...

  14. 78 FR 57672 - 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Science.gov (United States)

    2013-09-19

    ... 159, Global Positioning Systems (GPS) AGENCY: Federal Aviation Administration (FAA), U.S. Department... 159, Global Positioning Systems (GPS). SUMMARY: The FAA is issuing this notice to advise the public of the ninety-first meeting of the RTCA Special Committee 159, Global Positioning Systems (GPS) DATES...

  15. 77 FR 12106 - 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS)

    Science.gov (United States)

    2012-02-28

    ... 159, Global Positioning System (GPS) AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 159, Global Positioning System (GPS). SUMMARY: The..., Global Positioning System (GPS). DATES: The meeting will be held March 13-16, 2012, from 9 a.m.-4:30 p.m...

  16. USGS earthquake hazards program (EHP) GPS use case : earthquake early warning (EEW) and shake alert

    Science.gov (United States)

    2017-03-30

    GPS Adjacent Band Workshop VI RTCA Inc., Washington D.C., 30 March 2017. USGS GPS receiver use case - Real-Time GPS for EEW -Continued: CRITICAL EFFECT - The GNSS component of the Shake Alert system augments the inertial sensors and is especial...

  17. Pandora's electronic box: GPs reflect upon email communication with their patients

    Directory of Open Access Journals (Sweden)

    Felicity Goodyear-Smith

    2005-11-01

    Conclusion Study sample closely mirrored current NZ GP population. Although few GPs emailed with patients, many might once barriers are addressed. GPs had a collective view of the appropriate boundaries for email communication, routine tasks and the transmission of information. GPs would encourage professional debate regarding guidelines for good practice, managing demand and remuneration.

  18. Effect of an evidence-based answering service on GPs and their patients : a pilot study

    NARCIS (Netherlands)

    Verhoeven, A.A.; Schuling, J.

    2004-01-01

    OBJECTIVES: For general practitioners (GPs), an important obstacle to practising evidence-based medicine is lack of time. An evidence-based answering service was developed that took over searching and appraisal of medical evidence from the GPs. GPs sent in questions, and the informationist

  19. 77 FR 25510 - GPS Funds I, et al.; Notice of Application

    Science.gov (United States)

    2012-04-30

    ...] GPS Funds I, et al.; Notice of Application April 24, 2012. AGENCY: Securities and Exchange Commission... the Act to invest in certain financial instruments. Applicants: GPS Funds I, GPS Funds II (each a.... FOR FURTHER INFORMATION CONTACT: Laura L. Solomon, Senior Counsel, at (202) 551-6915 or Daniele...

  20. Using GPS to evaluate productivity and performance of forest machine systems

    Science.gov (United States)

    Steven E. Taylor; Timothy P. McDonald; Matthew W. Veal; Ton E. Grift

    2001-01-01

    This paper reviews recent research and operational applications of using GPS as a tool to help monitor the locations, travel patterns, performance, and productivity of forest machines. The accuracy of dynamic GPS data collected on forest machines under different levels of forest canopy is reviewed first. Then, the paper focuses on the use of GPS for monitoring forest...

  1. How do GPs recognize needs for palliative care in their patients?

    NARCIS (Netherlands)

    Claessen, S.J.; Francke, A.L.; Deliens, L.

    2012-01-01

    Aim: The aim of this study was to explore how GPs in the Netherlands recognize patients’ needs for palliative care. Methods: We conducted qualitative semi-structured interviews with about 25 GPs. These GPs were interviewed about recognition of the needs for palliative care in their patients and how

  2. GPS radio collar 3D performance as influenced by forest structure and topography

    Science.gov (United States)

    R. Scott Gamo; Mark A. Rumble; Fred Lindzey; Matt Stefanich

    2000-01-01

    Global Positioning System (GPS) telemetry enables biologists to obtain accurate and systematic locations of animals. Vegetation can block signals from satellites to GPS radio collars. Therefore, a vegetation dependent bias to telemetry data may occur which if quantified, could be accounted for. We evaluated the performance of GPS collars in 6 structural stage...

  3. Retained satellite information influences performance of GPS devices in a forested ecosystem

    Science.gov (United States)

    Katie M. Moriarty; Clinton W. Epps

    2015-01-01

    Global Positioning System (GPS) units used in animal telemetry often suffer from nonrandom data loss and location error. GPS units use stored satellite information to estimate locations, including almanac and ephemeris data reflecting satellite positions at weekly and at <4-hr temporal scales, respectively. Using the smallest GPS collars (45–51 g) available for...

  4. Aplicações e algoritmos de segurança rodoviária com o uso de sistemas de GPS e de comunicações WAVE

    OpenAIRE

    Cardoso, Fábio

    2013-01-01

    Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e Telecomunicações Os acidentes rodoviários são um problema de grande importância para toda a humanidade. O objetivo desta tese é desenvolver um sistema, através de comunicação WAVE, vehicle-tovehicle, capaz de alertar os automobilistas de risco de colisões. O sistema desenvolvido utiliza os dados recebidos por um sistema de GPS para o processamento dos algoritmos de segurança, estudados no estado ...

  5. High-sensitivity modified Glasgow prognostic score (HS-mGPS) Is superior to the mGPS in esophageal cancer patients treated with chemoradiotherapy

    OpenAIRE

    Chen, Peng; Fang, Min; Wan, Qiuyan; Zhang, Xuebang; Song, Tao; Wu, Shixiu

    2017-01-01

    The present study compared the prognostic value of the modified Glasgow prognostic score (mGPS) and high-sensitivity mGPS (HS-mGPS) in unresectable locally advanced esophageal squamous cell carcimona (LAESCC) patients treated with concurrent chemoradiotherapy (CCRT). The baseline data of 163 eligible patients were retrospectively collected. Patients with a C-reactive protein (CRP) ≤ 10 mg/l and albumin ≥ 35 g/l were allocated to mGPS-0 group. Patients with only elevated CRP (> 10 mg/l) were a...

  6. The Integration of GPS Navigator Device with Vehicles Tracking System for Rental Cars Firms

    OpenAIRE

    Omarah O. Alharaki; Fahad S. Alaieri; Akram M. Zeki

    2010-01-01

    The aim of this research is to integrate the GPS tracking system (tracking device and web-based application) with GPS navigator for rental cars, allowing the company to use various applications to monitor and manage the cars. This is enable the firms and customers to communicate with each other via the GPS navigator. The system should be developed by applying new features in GPS tracking application devices in vehicles. This paper also proposes new features that can be applied to the GPS Navi...

  7. Indoor/Outdoor Seamless Positioning Using Lighting Tags and GPS Cellular Phones for Personal Navigation

    Science.gov (United States)

    Namie, Hiromune; Morishita, Hisashi

    The authors focused on the development of an indoor positioning system which is easy to use, portable and available for everyone. This system is capable of providing the correct position anywhere indoors, including onboard ships, and was invented in order to evaluate the availability of GPS indoors. Although the performance of GPS is superior outdoors, there has been considerable research regarding indoor GPS involving sensitive GPS, pseudolites (GPS pseudo satellite), RFID (Radio Frequency IDentification) tags, and wireless LAN .However, the positioning rate and the precision are not high enough for general use, which is the reason why these technologies have not yet spread to personal navigation systems. In this regard, the authors attempted to implement an indoor positioning system using cellular phones with built-in GPS and infrared light data communication functionality, which are widely used in Japan. GPS is becoming increasingly popular, where GPGGS sentences of the NMEA outputted from the GPS receiver provide spatiotemporal information including latitude, longitude, altitude, and time or ECEF xyz coordinates. As GPS applications grow rapidly, spatiotemporal data becomes key to the ubiquitous outdoor and indoor seamless positioning services at least for the entire area of Japan, as well as to becoming familiar with satellite positioning systems (e.g. GPS). Furthermore, the authors are also working on the idea of using PDAs (Personal Digital Assistants), as cellular phones with built-in GPS and PDA functionality are also becoming increasingly popular.

  8. Transport on prescription: How can GPs contribute to the promotion of active transport?

    Science.gov (United States)

    Pistoll, Chance; Furler, John

    2017-10-01

    Active transport (ie walking, cycling, using public transport) can play a part in reducing non-communicable diseases (NCDs). Very little is known about how general practitioners (GPs) can contribute to promoting active transport. We explored GPs' ideas around active transport, and potential barriers and facilitators to its promotion in the clinical setting. Using a maximal variation sample, we conducted 10 semi-structured interviews with GPs in Victoria, Australia. The socioecological model informed data collection and analysis. The idea of active transport resonated with GPs. Limited awareness around active transport and safety concerns regarding commuter cycling were barriers to clinical promotion. GPs believed patients' health, cultural norms, socioeconomic position and access to supportive environments could facilitate participation. Future efforts should prioritise awareness of active transport among GPs. The perspectives of GPs would be valuable to policymakers, particularly in designing programs to mitigate inequalities around active transport access and use.

  9. Geração de Isolinhas, com dados obtidos por levantamento GPS/L1L2, mediante a técnica de Redes Neurais Artificiais = Generation of Isolines using GPS/L1L2 data and Artificial Neural Network technique

    Directory of Open Access Journals (Sweden)

    Elaine Cristine Barros de Souza

    2006-07-01

    Full Text Available O objetivo deste trabalho é mostrar uma alternativa para o processo deinterpolação empregado em Modelagem Digital do Terreno. Utilizando-se dados de levantamentos GPS coletados por meio de posicionamento relativo cinemático realizou-se um processo de interpolação por meio de Redes Neurais Artificiais (RNA. Os resultados foram comparados com os dados obtidos usando-se o algoritmo de interpolação Inverso doQuadrado de uma Distância (IQD para avaliar o comportamento das grades geradas por meio de análises qualitativas (isolinhas e MDT e quantitativas (resíduos. Conclui-se que o método testado é viável se comparado com o algoritmo IQD e, portanto, o uso de RNA apresenta-se adequado para a interpolação de dados GPS provenientes do processamento de fase das portadoras L1 e L2.The objective of this work is to show an alternative for theinterpolation process used in Digital Terrain Modeling. GPS surveying data of a kinematic relative positioning were interpolated by means of Artificial Neural Networks (ANN algorithm. The performance of the generated gridding was compared to the Inverse Square Distance interpolation algorithm data by means of qualitative (isolines and DTM and quantitative (residuals analyses. In conclusion, the tested method is viable if compared to the algorithm Inverse of the Square of a Distance. Therefore, the use of ANN is suitable for the interpolation of GPS data obtained from the L1 and L2 carriers phase processing.

  10. Uav Onboard Photogrammetry and GPS Positionning for Earthworks

    Science.gov (United States)

    Daakir, M.; Pierrot-Deseilligny, M.; Bosser, P.; Pichard, F.; Thom, C.

    2015-08-01

    Over the last decade, Unmanned Airbone Vehicles (UAVs) have been largely used for civil applications. Airborne photogrammetry has found place in these applications not only for 3D modeling but also as a measurement tool. Vinci-Construction-Terrassement is a private company specialized in public works sector and uses airborn photogrammetry as a mapping solution and metrology investigation tool on its sites. This technology is very efficient for the calculation of stock volumes for instance, or for time tracking of specific areas with risk of landslides. The aim of the present work is to perform a direct georeferencing of images acquired by the camera leaning on an embedded GPS receiver. UAV, GPS receiver and camera used are low-cost models and therefore data processing is adapted to this particular constraint.

  11. Tutorial GPS I programmi TGO e TTC di Trimble

    Directory of Open Access Journals (Sweden)

    Vittorio Grassi

    2005-10-01

    Full Text Available Sia questo articolo che quelli che seguiranno sui più diffusi programmi di elaborazione dei dati GPS circolanti in Italia, non pretendono d’essere ne’ saranno mai un manuale d’uso. Il loro scopo è quello di mettere in risalto le funzionalità del programma recensito sulla base di quanto esposto nell’articolo dello stesso autore, intitolato “L’elaborazione dei dati GPS” e pubblicato sul n° 2 di Geomedia 2005 ed è quindi visto solo sotto l’aspetto della elaborazione dei dati GPS e della loro compensazione.

  12. Global optimization applied to GPS positioning by ambiguity functions

    International Nuclear Information System (INIS)

    Baselga, Sergio

    2010-01-01

    Differential GPS positioning with carrier-phase observables is commonly done in a process that involves determination of the unknown integer ambiguity values. An alternative approach, named the ambiguity function method, was already proposed in the early days of GPS positioning. By making use of a trigonometric function ambiguity unknowns are eliminated from the functional model before the estimation process. This approach has significant advantages, such as ease of use and insensitivity to cycle slips, but requires such high accuracy in the initial approximate coordinates that its use has been practically dismissed from consideration. In this paper a novel strategy is proposed so that the need for highly accurate initial coordinates disappears: the application of a global optimization method to the ambiguity functions model. The use of this strategy enables the ambiguity function method to compete with the present prevailing approach of ambiguity resolution

  13. A transportation security system applying RFID and GPS

    Directory of Open Access Journals (Sweden)

    Ruijian Zhang

    2013-03-01

    Full Text Available Purpose: This paper is about developing a centralized, internet based security tool which utilizes RFID and GPS technology to identify drivers and track the load integrity. Design/methodology/approach: The system will accomplish the security testing in real-time using the internet and the U.S. Customs’ database (ACE. A central database and the interfaces and communication between the database and ACE will be established. After the vehicle is loaded, all openings of the tanker are sealed with disposable RFID tag seals. Findings/value: An RFID reader and GPS tracker wirelessly connected with the databases will serve as testing grounds for the implementation of security measures that can help prevent future terrorist attacks and help in ensuring that the goods and products are not compromised while in transit. The system will also reduce the labor work of security check to its minimum. 

  14. Adaptive Federal Kalman Filtering for SINS/GPS Integrated System

    Institute of Scientific and Technical Information of China (English)

    杨勇; 缪玲娟

    2003-01-01

    A new adaptive federal Kalman filter for a strapdown integrated navigation system/global positioning system (SINS/GPS) is given. The developed federal Kalman filter is based on the trace operation of parameters estimation's error covariance matrix and the spectral radius of update measurement noise variance-covariance matrix for the proper choice of the filter weight and hence the filter gain factors. Theoretical analysis and results from simulation in which the SINS/GPS was compared to conventional Kalman filter are presented. Results show that the algorithm of this adaptive federal Kalman filter is simpler than that of the conventional one. Furthermore, it outperforms the conventional Kalman filter when the system is undertaken measurement malfunctions because of its possession of adaptive ability. This filter can be used in the vehicle integrated navigation system.

  15. Smartphone-based integrated PDR/GPS/Bluetooth pedestrian location

    Science.gov (United States)

    Li, Xianghong; Wei, Dongyan; Lai, Qifeng; Xu, Ying; Yuan, Hong

    2017-02-01

    Typical indoor location method is fingerprint and traditional outdoor location system is GPS. Both of them are of poor accuracy and limited only for indoor or outdoor environments. As the smartphones are equipped with MEMS sensors, it means PDR can be widely used. In this paper, an algorithm of smartphone-based integrated PDR/GPS/Bluetooth for pedestrian location in the indoor/outdoor is proposed, which can be highly expected to realize seamless indoor/outdoor localization of the pedestrian. In addition, we also provide technologies to estimate orientation with Magnetometer and Gyroscope and detect context with output of sensors. The extensive experimental results show that the proposed algorithm can realize seamless indoor/outdoor localization.

  16. Seamless Guidance System Combining GPS, BLE Beacon, and NFC Technologies

    Directory of Open Access Journals (Sweden)

    Rung-Shiang Cheng

    2016-01-01

    Full Text Available Users rely increasingly on Location-Based Services (LBS and automated navigation/guidance systems nowadays. However, while such services are easily implemented in outdoor environments using Global Positioning System (GPS technology, a requirement still exists for accurate localization and guidance schemes in indoor settings. Accordingly, the present study proposes a system based on GPS, Bluetooth Low Energy (BLE beacons, and Near Field Communication (NFC technology. Through establishing graphic information and the design of algorithm, this study develops a guidance system for indoors and outdoors on smart phones, wishing to give user perfect smart life through this system. The proposed system is implemented on a smart phone and evaluated on a student campus environment. The experimental results confirm the ability of the proposed app to switch automatically from an outdoor mode to an indoor mode and to guide the user to requested target destination via the shortest possible route.

  17. Central and South America GPS geodesy - CASA Uno

    Science.gov (United States)

    Kellogg, James N.; Dixon, Timothy H.

    1990-01-01

    In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest GPS campaign in the world to date. A total of 43 GPS receivers collected approximately 590 station-days of data in American Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA Uno. Scientific goals of the project include measurements of strain in the northern Andes, subduction rates for the Cocos and Nazca plates beneath Central and South America, and relative motion between the Caribbean plate and South America. A second set of measurements are planned in 1991 and should provide preliminary estimates of crustal deformation and plate motion rates in the region.

  18. A GPS-Based Decentralized Control Method for Islanded Microgrids

    DEFF Research Database (Denmark)

    Golsorkhi, Mohammad; Lu, Dylan; Guerrero, Josep M.

    2017-01-01

    Coordinated control of distributed energy resources (DER) is essential for the operation of islanded microgrids (MGs). Conventionally, such coordination is achieved by drooping the frequency of the reference voltage versus active (or reactive) power. The conventional droop method ensures synchron......Coordinated control of distributed energy resources (DER) is essential for the operation of islanded microgrids (MGs). Conventionally, such coordination is achieved by drooping the frequency of the reference voltage versus active (or reactive) power. The conventional droop method ensures......, GPS timing technology is utilized to synchronize the DERs to a common reference frame, rotating at nominal frequency. In addition, an adaptive Q-f droop controller is introduced as a backup to ensure stable operation during GPS signal interruptions. In the context of the common reference frame, even...

  19. Understanding quit decisions in primary care: a qualitative study of older GPs.

    Science.gov (United States)

    Sansom, Anna; Calitri, Raff; Carter, Mary; Campbell, John

    2016-02-19

    To investigate the reasons behind intentions to quit direct patient care among experienced general practitioners (GPs) aged 50-60 years. Qualitative study based on semistructured interviews with GPs in the South West region of England. Transcribed interviews were analysed thematically. 23 GPs aged 50-60 years: 3 who had retired from direct patient care before age 60, and 20 who intended to quit direct patient care within the next 5 years. The analysis identified four key themes: early retirement is a viable option for many GPs; GPs have employment options other than undertaking direct patient care; GPs report feeling they are doing an (almost) undoable job; and GPs may have other aspirations that pull them away from practice. Findings from this study confirmed those from earlier research, with high workload, ageing and health, family and domestic life, and organisational change all influencing GPs' decisions about when to retire/quit direct patient care. However, in addition, GPs expressed feelings of insecurity and uncertainty regarding the future of general practice, low morale, and issues regarding accountability (appraisal and revalidation) and governance. Suggestions about how to help retain GPs within the active clinical workforce were offered, covering individual, practice and organisational levels. This research highlights aspects of the current professional climate for GPs that are having an impact on retirement decisions. Any future changes to policy or practice to help retain experienced GPs will benefit from this informed understanding of GPs' views. Key factors to take into account include: making the GP workload more manageable; managing change sympathetically; paying attention to GPs' own health; improving confidence in the future of general practice; and improving GP morale. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. Note to remote control of GPS observatory using GSM modem

    Czech Academy of Sciences Publication Activity Database

    Kottnauer, Pavel; Rucký, A.; Schenk, Vladimír; Schenková, Zdeňka

    24(131) (2003), s. 163-165 ISSN 1211-1910. [Czech-Polish Workshop on Recent Geodynamics of the Sudety Mts. and Adjacent Areas/4./. Lubawka, 07.11.2002-09.11.2002] R&D Projects: GA MŠk LN00A005 Institutional research plan: CEZ:AV0Z3046908 Keywords : GPS measurement * remote control Subject RIV: DB - Geology ; Mineralogy

  1. Methodology for GPS Synchronization Evaluation with High Accuracy

    OpenAIRE

    Li Zan; Braun Torsten; Dimitrova Desislava

    2015-01-01

    Clock synchronization in the order of nanoseconds is one of the critical factors for time based localization. Currently used time synchronization methods are developed for the more relaxed needs of network operation. Their usability for positioning should be carefully evaluated. In this paper we are particularly interested in GPS based time synchronization. To judge its usability for localization we need a method that can evaluate the achieved time synchronization with nanosecond accuracy. Ou...

  2. Methodology for GPS Synchronization Evaluation with High Accuracy

    OpenAIRE

    Li, Zan; Braun, Torsten; Dimitrova, Desislava Cvetanova

    2015-01-01

    Clock synchronization in the order of nanoseconds is one of the critical factors for time-based localization. Currently used time synchronization methods are developed for the more relaxed needs of network operation. Their usability for positioning should be carefully evaluated. In this paper, we are particularly interested in GPS-based time synchronization. To judge its usability for localization we need a method that can evaluate the achieved time synchronization with nanosecond accuracy. O...

  3. Non-traditional approaches to teaching GPS online

    Science.gov (United States)

    Matias, A.; Wolf, D. F., II

    2009-12-01

    Students are increasingly turning to the web for quality education that fits into their lives. Nonetheless, online learning brings challenges as well as a fresh opportunity for exploring pedagogical practices not present on traditional higher education programs, particularly in the sciences. A team of two dozen Empire State College-State University of New York instructional designers, faculty, and other staff are working on making science relevant to non-majors who may initially have anxiety about general education science courses. One of these courses, GPS and the New Geography, focuses on how Global Positioning System (GPS) technology provides a base for inquiry and scientific discovery from a range of environmental issues with local, regional, and global scope. GPS and the New Geography is an introductory level course developed under a grant supported by the Charitable Leadership Foundation. Taking advantage of the proliferation of tools currently available for online learning management systems, we explore current trends in Web 2.0 applications to aggregate and leverage data to create a nontraditional, interactive learning environment. Using our best practices to promote on-line discussion and interaction, these tools help engage students and foster deep learning. During the 15-week term students learn through case studies, problem-based exercises, and the use of scientific data; thus, expanding their spatial literacy and gain experience using real spatial technology tools to enhance their understanding of real-world issues. In particular, we present how the use of Mapblogs an in-house developed blogging platform that uses GIS interplaying with GPS units, interactive data presentations, intuitive visual working environments, harnessing RSS feeds, and other nontraditional Web 2.0 technology has successfully promoted active learning in the virtual learning environment.

  4. A variational regularization of Abel transform for GPS radio occultation

    OpenAIRE

    T.-K. Wee

    2018-01-01

    In the Global Positioning System (GPS) radio occultation (RO) technique, the inverse Abel transform of measured bending angle (Abel inversion, hereafter AI) is the standard means of deriving the refractivity. While concise and straightforward to apply, the AI accumulates and propagates the measurement error downward. The measurement error propagation is detrimental to the refractivity in lower altitudes. In particular, it builds up negative refractivity bias in the tropical ...

  5. A New Trajectory Similarity Measure for GPS Data

    KAUST Repository

    Ismail, Anas; Vigneron, Antoine E.

    2016-01-01

    We present a new algorithm for measuring the similarity between trajectories, and in particular between GPS traces. We call this new similarity measure the Merge Distance (MD). Our approach is robust against subsampling and supersampling. We perform experiments to compare this new similarity measure with the two main approaches that have been used so far: Dynamic Time Warping (DTW) and the Euclidean distance. © 2015 ACM.

  6. Norwegians GPs' use of electronic patient record systems.

    Science.gov (United States)

    Christensen, Tom; Faxvaag, Arild; Loerum, Hallvard; Grimsmo, Anders

    2009-12-01

    To evaluate GPs use of three major electronic patient record systems with emphasis on the ability of the systems to support important clinical tasks and to compare the findings with results from a study of the three major hospital-wide systems. A national, cross-sectional questionnaire survey was conducted in Norwegian primary care. 247 (73%) of 338 GPs responded. Proportions of the respondents who reported to use the EPR system to conduct 23 central clinical tasks, differences in the proportions of users of different EPR systems and user satisfaction and perceived usefulness of the EPR system were measured. The GPs reported extensive use of their EPR systems to support clinical tasks. There were no significant differences in functionality between the systems, but there were differences in reported software and hardware dysfunction and user satisfaction. The respondents reported high scores in computer literacy and there was no correlation between computer usage and respondent age or gender. A comparison with hospital physicians' use of three hospital-wide EPR systems revealed that GPs had higher usage than the hospital-based MDs. Primary care EPR systems support clinical tasks far better than hospital systems with better overall user satisfaction and reported impact on the overall quality of the work. EPR systems in Norwegian primary care that have been developed in accordance with the principles of user-centered design have achieved widespread adoption and highly integrated use. The quality and efficiency of the clinical work has increased in contrast to the situation of their hospital colleagues, who report more modest use and benefits of EPR systems.

  7. GPs' negotiation strategies regarding sick leave for subjective health complaints.

    Science.gov (United States)

    Nilsen, Stein; Malterud, Kirsti; Werner, Erik L; Maeland, Silje; Magnussen, Liv Heide

    2015-03-01

    To explore general practitioners' (GPs') specific negotiation strategies regarding sick-leave issues with patients suffering from subjective health complaints. Focus-group study. Nine focus-group interviews in three cities in different regions of Norway. 48 GPs (31 men, 17 women; age 32-65), participating in a course dealing with diagnostic practice and assessment of sickness certificates related to patients with subjective health complaints. The GPs identified some specific strategies that they claimed to apply when dealing with the question of sick leave for patients with subjective health complaints. The first step would be to build an alliance with the patient by complying with the wish for sick leave, and at the same time searching for information to acquire the patient's perspective. This position would become the basis for the main goal: motivating the patient for a rapid return to work by pointing out the positive effects of staying at work, making legal and moral arguments, and warning against long-term sick leave. Additional solutions might also be applied, such as involving other stakeholders in this process to provide alternatives to sick leave. GPs seem to have a conscious approach to negotiations of sickness certification, as they report applying specific strategies to limit the duration of sick leave due to subjective health complaints. This give-and-take way of handling sick-leave negotiations has been suggested by others to enhance return to work, and should be further encouraged. However, specific effectiveness of this strategy is yet to be proven, and further investigation into the actual dealings between doctor and patients in these complex encounters is needed.

  8. Assessing GPS Constellation Resiliency in an Urban Canyon Environment

    Science.gov (United States)

    2015-03-26

    ABMS ) is used to model complex adaptive systems (CAS) potentially made up of many different types of agents. North & Macal [25] state that, “Agent-based...modeling and simulation ( ABMS ) is founded on the notion that the whole of many systems or organizations is greater than the simple sum of its...satellite systems is challenging the capabilities provided by space assets. More specifically, the global positioning system (GPS) satellite

  9. A New Trajectory Similarity Measure for GPS Data

    KAUST Repository

    Ismail, Anas

    2016-08-08

    We present a new algorithm for measuring the similarity between trajectories, and in particular between GPS traces. We call this new similarity measure the Merge Distance (MD). Our approach is robust against subsampling and supersampling. We perform experiments to compare this new similarity measure with the two main approaches that have been used so far: Dynamic Time Warping (DTW) and the Euclidean distance. © 2015 ACM.

  10. Ionospheric threats to the integrity of airborne GPS users

    Science.gov (United States)

    Datta-Barua, Seebany

    The Global Positioning System (GPS) has both revolutionized and entwined the worlds of aviation and atmospheric science. As the largest and most unpredictable source of GPS positioning error, the ionospheric layer of the atmosphere, if left unchecked, can endanger the safety, or "integrity," of the single frequency airborne user. An augmentation system is a differential-GPS-based navigation system that provides integrity through independent ionospheric monitoring by reference stations. However, the monitor stations are not in general colocated with the user's GPS receiver. The augmentation system must protect users from possible ionosphere density variations occurring between its measurements and the user's. This study analyzes observations from ionospherically active periods to identify what types of ionospheric disturbances may cause threats to user safety if left unmitigated. This work identifies when such disturbances may occur using a geomagnetic measure of activity and then considers two disturbances as case studies. The first case study indicates the need for a non-trivial threat model for the Federal Aviation Administration's Local Area Augmentation System (LAAS) that was not known prior to the work. The second case study uses ground- and space-based data to model an ionospheric disturbance of interest to the Federal Aviation Administration's Wide Area Augmentation System (WAAS). This work is a step in the justification for, and possible future refinement of, one of the WAAS integrity algorithms. For both WAAS and LAAS, integrity threats are basically caused by events that may be occurring but are unobservable. Prior to the data available in this solar cycle, events of such magnitude were not known to be possible. This work serves as evidence that the ionospheric threat models developed for WARS and LAAS are warranted and that they are sufficiently conservative to maintain user integrity even under extreme ionospheric behavior.

  11. Directional Networking in GPS Denied Environments - Time Synchronization

    Science.gov (United States)

    2016-03-14

    RF-based measurements to synchronize time and measure node range.  Satellite Doppler: Using Doppler measurements from multiple satellites along...with satellite catalog data to determine time and position.  LTE : Use existing LTE base-stations for time and position.  Differential GPS: A...Opportunistic Signals: Opportunistically take advantage of existing RF signals (i.e., FM radio, DTV, LTE , etc.) transmitted from known locations

  12. Comparison of GPS and GLONASS Common-View Time Transfers

    Science.gov (United States)

    1992-12-01

    interest as an excellent additional source. For the past three years VNIIFTRI (Mendeleevo, Moscow Region, Russian Federation) and some other Russian time...Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 comparisons. Since June 1991, VNIIFTRI has operated a commercial GPS time receiver on...loan from the BIPM. Since February 1992, the BIPM has operated Russian GLONASS receiver on loan from the VNIIFTRI . Thii provides, for the first time

  13. Application of Seasonal Trend Loess to GPS data in Cascadia

    Science.gov (United States)

    Bal, A.; Bartlow, N. M.

    2016-12-01

    Plate Boundary Observatory GPS stations provide crucial data for the study of slow slip events and volcanic hazards in the Cascadia region. However, these GPS stations also record seasonal changes in deformation caused by hydrologic, atmospheric, and other seasonal loading. Removing these signals is necessary for accurately modeling the tectonic sources of deformation. Traditionally, seasonal trends in data been accounted for by fitting and removing sine curves from the data. However, not all seasonal trends follow a sinusoidal shape. Seasonal Trend Loess, or STL, is a filtering procedure for a decomposing a time series into trend, seasonal, and remainder components (Cleveland et. al, Journal of Official Statistics, 1990). STL has a simple design that consists of a sequence of applications of the loess smoother which allows for fast computation of large amounts of trend and seasonal smoothing. STL allows for non-sinusoidal shapes in seasonal deformation signals, and allows for evolution of seasonal signals over time. We applied Seasonal Trend Loess to GPS data from the Cascadia region. We compared our results to a traditional sine wave fit for seasonal removal at selected stations, including stations with slow slip event and volcanic signals. We hope that the STL method may be able to more accurately differentiate seasonal and tectonic deformation signals.

  14. Clustering of GPS velocities in the Mojave Block, southeastern California

    Science.gov (United States)

    Savage, James C.; Simpson, Robert W.

    2013-01-01

    We find subdivisions within the Mojave Block using cluster analysis to identify groupings in the velocities observed at GPS stations there. The clusters are represented on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. The most significant representation as judged by the gap test involves 4 clusters within the Mojave Block. The fault systems bounding the clusters from east to west are 1) the faults defining the eastern boundary of the Northeast Mojave Domain extended southward to connect to the Hector Mine rupture, 2) the Calico-Paradise fault system, 3) the Landers-Blackwater fault system, and 4) the Helendale-Lockhart fault system. This division of the Mojave Block is very similar to that proposed by Meade and Hager. However, no cluster boundary coincides with the Garlock Fault, the northern boundary of the Mojave Block. Rather, the clusters appear to continue without interruption from the Mojave Block north into the southern Walker Lane Belt, similar to the continuity across the Garlock Fault of the shear zone along the Blackwater-Little Lake fault system observed by Peltzer et al. Mapped traces of individual faults in the Mojave Block terminate within the block and do not continue across the Garlock Fault [Dokka and Travis, ].

  15. Estimating maneuvers for precise relative orbit determination using GPS

    Science.gov (United States)

    Allende-Alba, Gerardo; Montenbruck, Oliver; Ardaens, Jean-Sébastien; Wermuth, Martin; Hugentobler, Urs

    2017-01-01

    Precise relative orbit determination is an essential element for the generation of science products from distributed instrumentation of formation flying satellites in low Earth orbit. According to the mission profile, the required formation is typically maintained and/or controlled by executing maneuvers. In order to generate consistent and precise orbit products, a strategy for maneuver handling is mandatory in order to avoid discontinuities or precision degradation before, after and during maneuver execution. Precise orbit determination offers the possibility of maneuver estimation in an adjustment of single-satellite trajectories using GPS measurements. However, a consistent formulation of a precise relative orbit determination scheme requires the implementation of a maneuver estimation strategy which can be used, in addition, to improve the precision of maneuver estimates by drawing upon the use of differential GPS measurements. The present study introduces a method for precise relative orbit determination based on a reduced-dynamic batch processing of differential GPS pseudorange and carrier phase measurements, which includes maneuver estimation as part of the relative orbit adjustment. The proposed method has been validated using flight data from space missions with different rates of maneuvering activity, including the GRACE, TanDEM-X and PRISMA missions. The results show the feasibility of obtaining precise relative orbits without degradation in the vicinity of maneuvers as well as improved maneuver estimates that can be used for better maneuver planning in flight dynamics operations.

  16. GPS pro výukovou HW/SW platformu

    OpenAIRE

    Pajgrt, Ondřej

    2008-01-01

    Práce se zabývá popisem spojení výukové platformy FITkit s GPS modulem. Seznámíme se v ní s problematikou systému GPS z teoretického i praktického hlediska, s výukovou platformou FITkit a jejím obecným využitím.Také podrobně popisuje spojení těchto dvou systémů ve spolupracující celek. Rozebírá též různé komunikační rozhraní a protokoly, které byly pro toto spojení využity. Ve druhé části práce je pak uveden postup zpracovávání dat od GPS modulu až po výsledné zobrazení na monitoru, samotná i...

  17. The Effect of high temperature plasma on GPS satellite signals

    International Nuclear Information System (INIS)

    Aghanajafi, C.; Alizadeh, M.M.

    2002-01-01

    Ionospheric disturbances caused by pulses of electromagnetic radiation are observed in the propagation of radio signals. Specific events affecting particular aspects of radio propagation are sudden phase anomaly; sudden frequency deviation, sudden cosmic noise and short wave fade out. Global positioning System (GPS) is a space-based navigation system, developed by the United States, to satisfy the requirements for the military forces and the civilians to determine their position, velocity and time in a common reference system anywhere on or near the earth. The purpose of this paper is to calculate the effect of ionosphere on GPS satellite signals. In order to find this effects, calculation of the total column electron content is needed. The lack of data necessary to generate real Electron Density Profile versus altitude, latitude, time, season and solar activity; causes the introduction of a new method to reproduce the topside and bottom side component of the peak electron density. Electron density profiles computed in this method are compared with GPS derived profiles, which use observations of dual frequency receivers. Ionospheric range corrections, for signal point positioning, using two methods have also been discussed

  18. GPS sledovací systém

    OpenAIRE

    Hofman, Jan

    2010-01-01

    V práci je popsán základní princip a vlastnosti globálního pozičního systému GPS. Je zde přiblížena problematika určování polohy, rychlosti a nadmořské výšky. Tyto poznatky jsou dále použity pro návrh zařízení, které komunikuje s běžně vyráběným GPS přijímačem a z něj získané informace zpracovává a ukládá do paměti pro pozdější vyhodnocení The keystone and properties of Global Position System (GPS) are described in this thesis. The thesis explains questions of position, speed and elevation...

  19. GPS sekošanas sistēma

    OpenAIRE

    Striževskis, Andrejs

    2011-01-01

    Šajā darbā ir izskatītas GPS sekošanas iespējas privātās lietošanas sfērā, aprakstītas kartogrāfijas un navigācijas teorētisko pamatu izvēlētās nodaļas un piedāvāts bezmaksas risinājums, kas dod iespēju izmantot sekošanai GPS ierīces ar datora palīdzību un interneta pieslēgumu bez papildus servisiem, kā arī veidot tam nolūkam navigācijas kartes, piesaistot rastra attēlus Zemes ģeogrāfisko koordinātu sistēmai ar polinomiālās transformācijas palīdzību. Atslēgvārdi: GPS sekošana, GIS, navigāc...

  20. GPS time series at Campi Flegrei caldera (2000-2013

    Directory of Open Access Journals (Sweden)

    Prospero De Martino

    2014-05-01

    Full Text Available The Campi Flegrei caldera is an active volcanic system associated to a high volcanic risk, and represents a well known and peculiar example of ground deformations (bradyseism, characterized by intense uplift periods, followed by subsidence phases with some episodic superimposed mini-uplifts. Ground deformation is an important volcanic precursor, and, its continuous monitoring, is one of the main tool for short time forecast of eruptive activity. This paper provides an overview of the continuous GPS monitoring of the Campi Flegrei caldera from January 2000 to July 2013, including network operations, data recording and processing, and data products. In this period the GPS time series allowed continuous and accurate tracking of ground deformation of the area. Seven main uplift episodes were detected, and during each uplift period, the recurrent horizontal displacement pattern, radial from the “caldera center”, suggests no significant change in deformation source geometry and location occurs. The complete archive of GPS time series at Campi Flegrei area is reported in the Supplementary materials. These data can be usefull for the scientific community in improving the research on Campi Flegrei caldera dynamic and hazard assessment.

  1. Performance evaluation of GPS receiver under equatorial scintillation

    Directory of Open Access Journals (Sweden)

    Alison de Oliveira Moraes

    2009-06-01

    Full Text Available Equatorial scintillation is a phenomenon that occurs daily in the equatorial region after the sunset and affects radio signals that propagate through the ionosphere. Depending on the temporal and spatial situation, equatorial scintillation can represent a problem in the availability and precision of the Global Positioning System (GPS. This work is concerned with evaluating the impact of equatorial scintillation on the performance of GPS receivers. First, the morphology and statistical model of equatorial scintillation is briefly presented. A numerical model that generates synthetic scintillation data to simulate the effects of equatorial scintillation is presented. An overview of the main theoretical principles on GPS receivers is presented. The analytical models that describe the effects of scintillation at receiver level are presented and compared with numerical simulations using a radio software receiver and synthetic data. The results achieved by simulation agreed quite well with those predicted by the analytical models. The only exception is for links with extreme levels of scintillation and when weak signals are received.

  2. Comparison of the precision of three commonly used GPS models

    Directory of Open Access Journals (Sweden)

    E Chavoshi

    2016-04-01

    Full Text Available Introduction: Development of science in various fields has caused change in the methods to determine geographical location. Precision farming involves new technology that provides the opportunity for farmers to change in factors such as nutrients, soil moisture available to plants, soil physical and chemical characteristics and other factors with the spatial resolution of less than a centimeter to several meters to monitor and evaluate. GPS receivers based on precision farming operations specified accuracies are used in the following areas: 1 monitoring of crop and soil sampling (less than one meter accuracy 2 use of fertilizer, pesticide and seed work (less than half a meter accuracy 3 Transplantation and row cultivation (precision of less than 4 cm (Perez et al., 2011. In one application of GPS in agriculture, route guidance precision farming tractors in the fields was designed to reduce the transmission error that deviate from the path specified in the range of 50 to 300 mm driver informed and improved way to display (Perez et al., 2011. In another study, the system automatically guidance, based on RTK-GPS technology, precision tillage operations was used between and within the rows very close to the drip irrigation pipe and without damage to their crops at a distance of 50 mm (Abidine et al., 2004. In another study, to compare the accuracy and precision of the receivers, 5 different models of Trimble Mark GPS devices from 15 stations were mapped, the results indicated that minimum error was related to Geo XT model with an accuracy of 91 cm and maximum error was related to Pharos model with an accuracy of 5.62 m (Kindra et al., 2006. Due to the increasing use of GPS receivers in agriculture as well as the lack of trust on the real accuracy and precision of receivers, this study aimed to compare the positioning accuracy and precision of three commonly used GPS receivers models used to specify receivers with the lowest error for precision

  3. GPS coordinate time series measurements in Ontario and Quebec, Canada

    Science.gov (United States)

    Samadi Alinia, Hadis; Tiampo, Kristy F.; James, Thomas S.

    2017-06-01

    New precise network solutions for continuous GPS (cGPS) stations distributed in eastern Ontario and western Québec provide constraints on the regional three-dimensional crustal velocity field. Five years of continuous observations at fourteen cGPS sites were analyzed using Bernese GPS processing software. Several different sub-networks were chosen from these stations, and the data were processed and compared to in order to select the optimal configuration to accurately estimate the vertical and horizontal station velocities and minimize the associated errors. The coordinate time series were then compared to the crustal motions from global solutions and the optimized solution is presented here. A noise analysis model with power-law and white noise, which best describes the noise characteristics of all three components, was employed for the GPS time series analysis. The linear trend, associated uncertainties, and the spectral index of the power-law noise were calculated using a maximum likelihood estimation approach. The residual horizontal velocities, after removal of rigid plate motion, have a magnitude consistent with expected glacial isostatic adjustment (GIA). The vertical velocities increase from subsidence of almost 1.9 mm/year south of the Great Lakes to uplift near Hudson Bay, where the highest rate is approximately 10.9 mm/year. The residual horizontal velocities range from approximately 0.5 mm/year, oriented south-southeastward, at the Great Lakes to nearly 1.5 mm/year directed toward the interior of Hudson Bay at stations adjacent to its shoreline. Here, the velocity uncertainties are estimated at less than 0.6 mm/year for the horizontal component and 1.1 mm/year for the vertical component. A comparison between the observed velocities and GIA model predictions, for a limited range of Earth models, shows a better fit to the observations for the Earth model with the smallest upper mantle viscosity and the largest lower mantle viscosity. However, the

  4. Interaction between subdaily Earth rotation parameters and GPS orbits

    Science.gov (United States)

    Panafidina, Natalia; Seitz, Manuela; Hugentobler, Urs

    2013-04-01

    In processing GPS observations the geodetic parameters like station coordinates and ERPs (Earth rotation parameters) are estimated w.r.t. the celestial reference system realized by the satellite orbits. The interactions/correlations between estimated GPS orbis and other parameters may lead to numerical problems with the solution and introduce systematic errors in the computed values: the well known correlations comprise 1) the correlation between the orbital parameters determining the orientation of the orbital plane in inertial space and the nutation and 2) in the case of estimating ERPs with subdaily resolution the correlation between retrograde diurnal polar motion and nutation (and so the respective orbital elements). In this contribution we study the interaction between the GPS orbits and subdaily model for the ERPs. Existing subdaily ERP model recommended by the IERS comprises ~100 terms in polar motion and ~70 terms in Universal Time at diurnal and semidiurnal tidal periods. We use a long time series of daily normal equation systems (NEQ) obtaine from GPS observations from 1994 till 2007 where the ERPs with 1-hour resolution are transformed into tidal terms and the influence of the tidal terms with different frequencies on the estimated orbital parameters is considered. We found that although there is no algebraic correlation in the NEQ between the individual orbital parameters and the tidal terms, the changes in the amplitudes of tidal terms with periods close to 24 hours can be better accmodated by systematic changes in the orbital parameters than for tidal terms with other periods. Since the variation in Earth rotation with the period of siderial day (23.93h, tide K1) in terrestrial frame has in inertial space the same period as the period of revolution of GPS satellites, the K1 tidal term in polar motion is seen by the satellites as a permanent shift. The tidal terms with close periods (from ~24.13h to ~23.80h) are seen as a slow rotation of the

  5. GPS-Based Highway Performance Monitoring Performance Monitoring Using GPS: Characterization of Travel Speeds on any Roadway Segment

    OpenAIRE

    Kornhauser, Alain L.

    2012-01-01

    Presented is a characterization of travel speed on any roadway segment based on probe vehicle position data. Most of the characterization is based position data obtained from GPS receivers because of their high precision and their increasing availability. Comparison is also made to Qualcomm’s Automatic Satellite Position Reporting (QASPR) system because of its long history (10+ years) of extensive use by the long-haul trucking industry. Described is the use of these data in conjunction with d...

  6. Remote reference processing in MT survey using GPS clock; MT ho ni okeru GPS wo mochiita jikoku doki system

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, K; Inoue, J; Takasugi, S [Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Kosuge, S [DRICO Co. Ltd., Tokyo (Japan)

    1996-05-01

    A report is given about the application of a synchronizing system using clock signals from GPS satellites to a remote reference method which is a technique to reject noise from the MT method. This system uses the C/A code out of the L1 band waves from NAVSTAR/GPS satellites. The new system was operated in MT method-using investigations conducted at China Peninsula, Aichi Prefecture, and Izu Peninsula, Shizuoka Prefecture, with the reference points placed several 100km away in Iwate Prefecture on both occasions. It was found as the result that it is basically possible to catch signals from the GPS at any place, that the signals are accurate enough to be applied to time synchronization for the MT method, and that the signals assure a far remote reference method with a separation of several 100km between the sites involved. The referencing process at high frequencies whose feasibility had been doubted proved a success when highly correlated signals were exchanged between two stations over a distance of several 100km. 5 refs., 9 figs.

  7. Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

    Science.gov (United States)

    Afifi, Akram; El-Rabbany, Ahmed

    2015-06-19

    This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

  8. para palmito

    Directory of Open Access Journals (Sweden)

    Francisco Paulo Chaimsohn

    2007-01-01

    Full Text Available Densidades de siembra, arreglos espaciales y fertilización en pejibaye (Bactris gasipaes cv Diamantes-10 para palmito. La investigación se llevó a cabo en la Estación Experimental Los Diamantes (Guápiles, Costa Rica, el 3 de octubre del 2003, cuyo objetivo fue la evaluación del efecto de diferentes densidades de siembra (3.333, 5.000 y 6.666 plantas/ha, arreglos espaciales, y diversos métodos de fertilización (química, orgánica, sobre el crecimiento de las plantas de pejibaye para producción de palmito. Se consideraron las variables diámetro y altura del tallo primario y el número de hojas y rebrotes como indicadores de producción. El período de evolución abarcó sólo los primeros 25 meses de crecimiento en el campo. El número de hojas, la altura y el diámetro del tallo no mostraron diferencias de respuesta relevantes. Sólo el número de rebrotes disminuyó al aumentar la densidad de la población, cuando se midió a los 15 meses de edad. El efecto de la fertilización se hizo evidente después de la primera cosecha, realizada a los 20 meses, debido al aumento de la competencia entre plantas, ahora más desarrolladas. Fue entonces cuando la fertilización química indujo la producción de un mayor número y vigor de los rebrotes. Sin embargo, las prácticas evaluadas 25 meses después de la siembra, no habían infl uido hasta ese momento en el número de palmitos cosechados, ni tampoco había afectado las características físicas de los sectores foliar y caulinar del palmito.

  9. SISTEMA WEB DE GEOLOCALIZACIÓN Y MONITOREO DE LA TORTUGA PODOCNEMIS LEWYANA EN EL RÍO SINÚ, MEDIANTE EL USO DE ANTENAS VHF Y DISPOSITIVOS GPS

    Directory of Open Access Journals (Sweden)

    Mario Macea Anaya

    2016-03-01

    Full Text Available Este trabajo tiene como finalidad el diseño e implementación de una aplicación para el monitoreo de las Tortugas de Río Podocnemis Lewyana, utilizando las tecnologías GPS (Global Positioning System y VHF (Very High Frequency. La aplicación permite apoyar los procesos de conservación y recuperación de la especie en el Departamento de Córdoba, en las poblaciones de Caño Viejo y Cotocá Arriba del municipio Santa Cruz de Lorica, Colombia. El uso de esa herramienta está dirigido a biólogos y personas de las comunidades rurales dedicadas a conservar dicha especie. En el desarrollo del proyecto se utilizaron 18 Tortugas de Río para su monitoreo. El resultado del trabajo es la aplicación Web Podocnemis-Soft. Su funcionamiento se basa en un dispositivo GPS y VHF, ubicado en una o varias de las tortugas Podocnemis Lewyana; los dispositivos envían los datos de la ubicación de la tortuga hasta un servidor para su procesamiento y posterior visualización de la información.

  10. Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

    Directory of Open Access Journals (Sweden)

    L. Zhao

    2013-01-01

    Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

  11. Analysis of signal acquisition in GPS receiver software

    Directory of Open Access Journals (Sweden)

    Vlada S. Sokolović

    2011-01-01

    Full Text Available This paper presents a critical analysis of the flow signal processing carried out in GPS receiver software, which served as a basis for a critical comparison of different signal processing architectures within the GPS receiver. It is possible to achieve Increased flexibility and reduction of GPS device commercial costs, including those of mobile devices, by using radio technology software (SDR, Software Defined Radio. The SDR application can be realized when certain hardware components in a GPS receiver are replaced. Signal processing in the SDR is implemented using a programmable DSP (Digital Signal Processing or FPGA (Field Programmable Gate Array circuit, which allows a simple change of digital signal processing algorithms and a simple change of the receiver parameters. The starting point of the research is the signal generated on the satellite the structure of which is shown in the paper. Based on the GPS signal structure, a receiver is realized with a task to extract an appropriate signal from the spectrum and detect it. Based on collected navigation data, the receiver calculates the position of the end user. The signal coming from the satellite may be at the carrier frequencies of L1 and L2. Since the SPS is used in the civil service, all the tests shown in the work were performed on the L1 signal. The signal coming to the receiver is generated in the spread spectrum technology and is situated below the level of noise. Such signals often interfere with signals from the environment which presents a difficulty for a receiver to perform proper detection and signal processing. Therefore, signal processing technology is continually being improved, aiming at more accurate and faster signal processing. All tests were carried out on a signal acquired from the satellite using the SE4110 input circuit used for filtering, amplification and signal selection. The samples of the received signal were forwarded to a computer for data post processing, i. e

  12. GPs' attitudes, beliefs and behaviours regarding exercise for chronic knee pain: a questionnaire survey.

    Science.gov (United States)

    Cottrell, Elizabeth; Foster, Nadine E; Porcheret, Mark; Rathod, Trishna; Roddy, Edward

    2017-06-17

    The aim of this study was to investigate general practitioners' (GPs) attitudes, beliefs and behaviours regarding the use of exercise for patients with chronic knee pain (CKP) attributable to osteoarthritis. Primary care GPs in the UK. 5000 GPs, randomly selected from Binley's database, were mailed a cross-sectional questionnaire survey. GPs' attitudes and beliefs were investigated using attitude statements, and reported behaviours were identified using vignette-based questions. GPs were invited to report barriers experienced when initiating exercise with patients with CKP RESULTS: 835 (17%) GPs responded. Overall, GPs were positive about general exercise for CKP. 729 (87%) reported using exercise, of which, 538 (74%) reported that they would use both general and local (lower limb) exercises. However, only 92 (11% of all responding) GPs reported initiating exercise in ways aligning with best-evidence recommendations. 815 (98%) GPs reported barriers in using exercise for patients with CKP, most commonly, insufficient time in consultations (n=419; 51%) and insufficient expertise (n=337; 41%). While GPs' attitudes and beliefs regarding exercise for CKP were generally positive, initiation of exercise was often poorly aligned with current recommendations, and barriers and uncertainties were reported. GPs' use of exercise may be improved by addressing the key barriers of time and expertise, by developing a pragmatic approach that supports GPs to initiate individualised exercise, and/or by other professionals taking on this role. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  13. Towards 10(exp 9) GPS geodesy: Vector baselines, Earth rotation and reference frames

    Science.gov (United States)

    Schutz, Bob E.

    1994-01-01

    Effort during the period form January 1, 1993 to December 31, 1993 were in the following areas: GPS orbit accuracy assessments and efforts to improve the accuracy; analysis and effects of GPS receiver antenna phase center variation; analysis of global GPS data being collected for the IGS campaign; and analysis of regional (south west Pacific) campaign data. A brief summary of each of the above activities is presented.

  14. Data Integration from GPS and Inertial Navigation Systems for Pedestrians in Urban Area

    OpenAIRE

    Krzysztof Bikonis; Jerzy Demkowicz

    2013-01-01

    The GPS system is widely used in navigation and the GPS receiver can offer long-term stable absolute positioning information. The overall system performance depends largely on the signal environments. The position obtained from GPS is often degraded due to obstruction and multipath effect caused by buildings, city infrastructure and vegetation, whereas, the current performance achieved by inertial navigation systems (INS) is still relatively poor due to the large inertial sensor errors. The c...

  15. Anti-Jam GPS Antennas for Wearable Dismounted Soldier Navigation Systems

    Science.gov (United States)

    2016-06-01

    GPS antenna, the Novatel GAJT-700M/ L CRPA is currently being considered, as shown in Fig. 6. Fig. 6 A basic 7-element CRPA (right) compared with a...ARL-TR-7670 ● JUNE 2016 US Army Research Laboratory Anti-Jam GPS Antennas for Wearable Dismounted Soldier Navigation Systems...longer needed. Do not return it to the originator. ARL-TR-7670 ● JUNE 2016 US Army Research Laboratory Anti-Jam GPS Antennas for

  16. Performance Enhancement of Land Vehicle Positioning Using Multiple GPS Receivers in an Urban Area

    OpenAIRE

    Song, Jong-Hwa; Jee, Gyu-In

    2016-01-01

    The Global Positioning System (GPS) is the most widely used navigation system in land vehicle applications. In urban areas, the GPS suffers from insufficient signal strength, multipath propagation and non-line-of-sight (NLOS) errors, so it thus becomes difficult to obtain accurate and reliable position information. In this paper, an integration algorithm for multiple receivers is proposed to enhance the positioning performance of GPS for land vehicles in urban areas. The pseudoranges of multi...

  17. Thermal structure of intense convective clouds derived from GPS radio occultations

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Randel, W. J.; Ho, S. -P.

    2012-01-01

    Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature...... behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS...

  18. Thermal structure of intense convective clouds derived from GPS radio occultations

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Randel, W. J.; Ho, S.-P.

    2011-01-01

    Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature...... behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS...

  19. A PRECISÃO POSSÍVEL COM GPS L1-C/A EM GEORREFERENCIAMENTO: O DESAFIO DO MULTICAMINHO

    OpenAIRE

    Evandro Palma

    2005-01-01

    Desde a criação do sistema Navstar/GPS, várias fontes de erros nas observáveis foram sendo identificadas e estudadas pela comunidade científica, tais como a solução de ambigüidades, o atraso ionosférico e o não sincronismo de relógios. O problema do erro causado pelo multicaminho, no entanto, persiste como um desafio, especialmente para aplicações que exigem maior acurácia e precisão. No caso do Brasil, com a promulgação em 2001 da Lei 10267 que institui o Cadastro Nacional de Imóveis Rurais,...

  20. What do troubled adolescents expect from their GPs?

    Science.gov (United States)

    Tudrej, Benoit V; Heintz, Anne-Laure; Ingrand, Pierre; Gicquel, Ludovic; Binder, Philippe

    2016-12-01

    Adolescents often have emotional and behavioural problems that general practitioners are likely to miss. While nearly 80% of them consult their GP every year, it is usually for physical, not psychological reasons. Trust in their GPs in necessary for screening. To identify the key quality desired by adolescents for them to feel free to confide in GPs. To determine whether this quality differed according to gender, level of at-risk behaviours or interlocutor: friend, parent or GP. A descriptive cross-sectional study was conducted in 182 French educational institutions chosen by lot. Fifteen-year-olds completed a self-administered questionnaire under examination conditions. While the questions on behaviour were drawn from the cross-national survey entitled 'Health behaviour in school-aged children (HBSC),' the questions on conditions conducive to trust were drawn from previous studies. A total of 1817 (911 boys, 906 girls) questionnaires were analysed. Adolescents said they seldom confided. The main quality they expected from a GP to whom they could confide in was 'honesty', which meant ensuring secrecy, refraining from judgment, and putting forward the right questions. This priority was modified by neither gender nor experience with health-risk behaviour. The quality of 'reliability' was more closely associated with their parents or friends, while 'emotionality' was cited less often. To gain the trust of adolescents, GPs have to be sincere and non-manipulative and have the ability to ensure confidentiality and to put forward the right questions without passing judgment. Can this be verified during consultations? Prospective studies could shed light on this point.[Box: see text].

  1. GPS Technology for the Development of Business Information Systems

    Directory of Open Access Journals (Sweden)

    Mihaela MURESAN

    2006-01-01

    Full Text Available The use of the GPS system opens the way for a new generation of information systems using geospatial information. The geoinformation provided by the GPS system could be used in various applications, such as: positioning and monitoring the behavior of the objects static or in movement, navigating, measuring the surfaces etc. These new approach introduces the concept of image handling for decision support which involves a better geoimage handling in order to make easier for decision makers to discover, access, and integrate geospatial information in decision-support scenarios. A very useful application is the risk management for the vehicles with direct benefits in terms of competitivity, for the transport organizations, and of road transport safety, for the society. The safety of the road transport is a priority in the light of the policy on trans-European networks for transport (TEN-T and according to the actual and future trend related to the freight on the road (75% of the freight goes by road according to the Third report on Economic and social Cohesion, February 2004. The implementation of a high technology solution based on GPS communication for the monitoring of transports along the whole itinerary and the immediate alert in case of various non-procedural behavior, increases the road transport security and avoids accidents and disasters. Minimizing the risk for the road transport is a general concern at the EU level, as well as at the national level. The design and the development of transport risk management information systems will contribute to stimulate the implementation of the new technologies in the current transport organizations' activity and to change the internal processes according to the philosophy introduced by the information society. The transport risk management system integrates detection and communication intelligent equipment, various communication technologies and networking solutions with powerful computers and

  2. The Permanent GPS Network In The Iberian Peninsula

    Science.gov (United States)

    Fernandes, R. M. S.; Bastos, L.; Ambrosius, B. A. C.; Noomen, R.

    In recent years, the number of permanent GPS sites in the Iberia Peninsula has in- creased significantly: in the beginning of 1996 there were just 2 sites with publicly available data. This number had risen to 15 by the end of 1999, and recently (end of 2001), it has reached 18. For many sites, the observation time-span is already suffi- ciently long to derive a reliable estimate of the motion of the stations. Combined with the relatively good geographical distribution of the sites, this velocity field contains unique information to study the tectonics of the Iberian Peninsula, both internally and with respect to the rest of Europe. In the framework of a combined DEOS-AOUP research project called GIN (GPS Iberian Network), the data of all available GPS sites in the region (including some in North Africa, the Azores Archipelago and France) are being processed on a daily basis since the middle of 2000 (with backward processing extending to January 1996). Following this project, DEOS became an official LAC (Local Analysis Centre) of EU- REF in the beginning of 2001. The DEOS weekly solutions are included in the official EUREF analysis chain, resulting in weekly coordinate solutions for the entire EU- REF network. The two solutions (GIN &EUREF) are computed by the DEOS-AOUP group using the same software, but applying different strategies. The differences in the solutions are analysed in order to pinpoint data problems and processing errors. Furthermore, the GIN velocity field is compared with the one derived from the offi- cial EUREF solution. Special attention is paid to the different procedures to link the solutions into a unified reference frame. Finally, this paper presents a preliminary interpretation of the contemporary tectonics of the Iberian Peninsula based on the derived velocity fields. There is evidence of significant intra-plate deformation in the Iberia region and there are indications that the Iberian block exhibits a differential motion with respect to

  3. Estimating Vehicle Fuel Consumption and Emissions Using GPS Big Data

    Directory of Open Access Journals (Sweden)

    Zihan Kan

    2018-03-01

    Full Text Available The energy consumption and emissions from vehicles adversely affect human health and urban sustainability. Analysis of GPS big data collected from vehicles can provide useful insights about the quantity and distribution of such energy consumption and emissions. Previous studies, which estimated fuel consumption/emissions from traffic based on GPS sampled data, have not sufficiently considered vehicle activities and may have led to erroneous estimations. By adopting the analytical construct of the space-time path in time geography, this study proposes methods that more accurately estimate and visualize vehicle energy consumption/emissions based on analysis of vehicles’ mobile activities (MA and stationary activities (SA. First, we build space-time paths of individual vehicles, extract moving parameters, and identify MA and SA from each space-time path segment (STPS. Then we present an N-Dimensional framework for estimating and visualizing fuel consumption/emissions. For each STPS, fuel consumption, hot emissions, and cold start emissions are estimated based on activity type, i.e., MA, SA with engine-on and SA with engine-off. In the case study, fuel consumption and emissions of a single vehicle and a road network are estimated and visualized with GPS data. The estimation accuracy of the proposed approach is 88.6%. We also analyze the types of activities that produced fuel consumption on each road segment to explore the patterns and mechanisms of fuel consumption in the study area. The results not only show the effectiveness of the proposed approaches in estimating fuel consumption/emissions but also indicate their advantages for uncovering the relationships between fuel consumption and vehicles’ activities in road networks.

  4. Estimating Vehicle Fuel Consumption and Emissions Using GPS Big Data.

    Science.gov (United States)

    Kan, Zihan; Tang, Luliang; Kwan, Mei-Po; Zhang, Xia

    2018-03-21

    The energy consumption and emissions from vehicles adversely affect human health and urban sustainability. Analysis of GPS big data collected from vehicles can provide useful insights about the quantity and distribution of such energy consumption and emissions. Previous studies, which estimated fuel consumption/emissions from traffic based on GPS sampled data, have not sufficiently considered vehicle activities and may have led to erroneous estimations. By adopting the analytical construct of the space-time path in time geography, this study proposes methods that more accurately estimate and visualize vehicle energy consumption/emissions based on analysis of vehicles' mobile activities ( MA ) and stationary activities ( SA ). First, we build space-time paths of individual vehicles, extract moving parameters, and identify MA and SA from each space-time path segment (STPS). Then we present an N-Dimensional framework for estimating and visualizing fuel consumption/emissions. For each STPS, fuel consumption, hot emissions, and cold start emissions are estimated based on activity type, i.e., MA , SA with engine-on and SA with engine-off. In the case study, fuel consumption and emissions of a single vehicle and a road network are estimated and visualized with GPS data. The estimation accuracy of the proposed approach is 88.6%. We also analyze the types of activities that produced fuel consumption on each road segment to explore the patterns and mechanisms of fuel consumption in the study area. The results not only show the effectiveness of the proposed approaches in estimating fuel consumption/emissions but also indicate their advantages for uncovering the relationships between fuel consumption and vehicles' activities in road networks.

  5. Attracting and retaining GPs: a stakeholder survey of priorities.

    Science.gov (United States)

    Lorant, Vincent; Geerts, Charlotte; Duchesnes, Christiane; Goedhuys, Jo; Ryssaert, Lynn; Remmen, Roy; D'hoore, William

    2011-07-01

    Despite being a key player in the healthcare system, training and practising general practice has become less attractive in many countries and is in need of reform. To identify political priorities for improving GPs' attraction to the profession and their retention within it. Stakeholder face-to-face survey in Belgium, 2008. A total of 102 key stakeholders were recruited from policymakers, professional groups, academia, GP leaders, and the media. All interviewees were asked to score 23 policies on four criteria: effectiveness in attracting and retaining GPs, cost to society, acceptance by other health professionals, and accessibility of care. An overall performance score was computed (from -3 to +3) for each type of policy - training, financing, work-life balance, practice organisation, and governance - and for innovative versus conservative policies. Practice organisation policies and training policies received the highest scores (mean score ≥ 1.11). Financing policies, governance, and work-life balance policies scored poorly (mean score ≤ 0.65) because they had negative effects, particularly in relation to cost, acceptance, and accessibility of care. Stakeholders were keen on moving GPs towards team work, improving their role as care coordinator, and helping them to offload administrative tasks (score ≥ 1.4). They also favoured moves to increase the early and integrated exposure of all medical students to general practice. Overall, conservative policies were better scored than innovative ones (beta = -0.16, 95% confidence interval = -0.28 to -0.03). The reforming of general practice is made difficult by the small-step approach, as well as the importance of decision criteria related to cost, acceptance, and access.

  6. Quantifying movement demands of AFL football using GPS tracking.

    Science.gov (United States)

    Wisbey, Ben; Montgomery, Paul G; Pyne, David B; Rattray, Ben

    2010-09-01

    Global positioning system (GPS) monitoring of movement patterns is widespread in elite football including the Australian Football League (AFL). However documented analysis of this activity is lacking. We quantified the movement patterns of AFL football and differences between nomadic (midfield), forward and defender playing positions, and determined whether the physical demands have increased over a four season period. Selected premiership games were monitored during the 2005 (n=80 game files), 2006 (n=244), 2007 (n=632) and 2008 (n=793) AFL seasons. Players were fitted with a shoulder harness containing a GPS unit. GPS data were downloaded after games and the following measures extracted: total distance (km), time in various speed zones, maximum speed, number of surges, accelerations, longest continuous efforts and a derived exertion index representing playing intensity. In 2008 nomadic players covered per game 3.4% more total distance (km), had 4.8% less playing time (min), a 17% higher exertion index (per min), and 23% more time running >18kmh(-1) than forwards and defenders (all p<0.05). Physical demands were substantially higher in the 2008 season compared with 2005: an 8.4% increase in mean speed, a 14% increase in intensity (exertion index) and a 9.0% decrease in playing time (all p<0.05). Nomadic players in AFL work substantially harder than forwards and defenders in covering more ground and at higher running intensities. Increases in the physical demands of AFL football were evident between 2005 and 2008. The increasing speed of the game has implications for game authorities, players and coaching staff.

  7. Ionospheric Mapping Software Ensures Accuracy of Pilots GPS

    Science.gov (United States)

    2015-01-01

    IonoSTAGE and SuperTruth software are part of a suite created at the Jet Propulsion Laboratory to enable the Federal Aviation Administration's Wide Area Augmentation System, which provides pinpoint accuracy in aircraft GPS units. The system, used by more than 73,000 planes, facilitates landings under adverse conditions at small airports. In 2013, IonoSTAGE and SuperTruth found their first commercial license when NEC, based in Japan, with US headquarters in Irving, Texas, licensed the entire suite.

  8. SAFETY MANAGEMENT FOR WOMEN THROUGH AUTOMATIC GPS LOCATION TRACKER

    OpenAIRE

    P.Nivetha*1, S.Kiruthika2 & J.B.Kavitha3

    2018-01-01

    The project “SAFETY MANAGEMENT FOR WOMEN THROUGH AUTOMATIC GPS LOCATION TRACKER” is designed using Standard Android 4.0.3 platform. The platform used to develop the application is Eclipse IDE (Mars) with Java 1.6 Standard Edition. It’s an android app which will help people in their crucial time. For example if a person is in trouble and he needs a help so there should be an app through which he/she can contact with their one to help them by just clicking on one button, it will automatically s...

  9. Constraints on dike propagation from continuous GPS measurements

    Science.gov (United States)

    Segall, P.; Cervelli, Peter; Owen, S.; Lisowski, M.; Miklius, Asta

    2001-01-01

    The January 1997 East Rift Zone eruption on Kilauea volcano, Hawaii, occurred within a network of continuous Global Positioning System (GPS) receivers. The GPS measurements reveal the temporal history of deformation during dike intrusion, beginning ??? 8 hours prior to the onset of the eruption. The dike volume as a function of time, estimated from the GPS data using elastic Green's functions for a homogeneous half-space, shows that only two thirds of the final dike volume accumulated prior to the eruption and the rate of volume change decreased with time. These observations are inconsistent with simple models of dike propagation, which predict accelerating dike volume up to the time of the eruption and little or no change thereafter. Deflationary tilt changes at Kilauea summit mirror the inferred dike volume history, suggesting that the rate of dike propagation is limited by flow of magma into the dike. A simple, lumped parameter model of a coupled dike magma chamber system shows that the tendency for a dike to end in an eruption (rather than intrusion) is favored by high initial dike pressures, compressional stress states, large, compressible magma reservoirs, and highly conductive conduits linking the dike and source reservoirs. Comparison of model predictions to the observed dike volume history, the ratio of erupted to intruded magma, and the deflationary history of the summit magma chamber suggest that most of the magma supplied to the growing dike came from sources near to the eruption through highly conductive conduits. Interpretation is complicated by the presence of multiple source reservoirs, magma vesiculation and cooling, as well as spatial variations in dike-normal stress. Reinflation of the summit magma chamber following the eruption was measured by GPS and accompanied a rise in the level of the Pu'u O'o lava lake. For a spheroidal chamber these data imply a summit magma chamber volume of ??? 20 km3, consistent with recent estimates from seismic

  10. Measuring Magnetic Declination With Compass, GPS and Virtual Globes

    Science.gov (United States)

    O'Brien, W. P.

    2006-12-01

    Using virtual globe (VG) imagery to determine geographic bearing and a compass to determine magnetic bearing yielded acceptable experimental magnetic declination values for large linear physical features at 13 sites in the western continental United States. The geographic bearing of each feature was determined from measurements involving the latitude/longitude coordinate system associated with the VG image (from World Wind or Google Earth). The corresponding magnetic bearing was measured on the ground at the feature with a hand-bearing compass calibrated in 1-degree subdivisions. A sequence of GPS trackpoints, recorded while traveling along the feature either in an automobile or on foot, unambiguously identified the pertinent portion of the feature (a straight segment of a road, for example) when plotted on the VG image. For each physical feature located on a VG image, its geographic bearing was determined directly using on-screen measurement tools available with the VG program or by hand using ruler/protractor methods with printed copies of the VG image. An independent (no use of VG) geographic bearing was also extracted from the slope of a straight-line fit to a latitude/longitude plot of each feature's GPS coordinates, a value that was the same (to within the inherent uncertainty of the data) as the VG-determined bearing, thus validating this procedure for finding geographic bearings. Differences between the VG bearings and the magnetic bearings yielded experimental magnetic declination values within one degree (8 within 0.5 degree) of expected values. From the point of view of physics and geophysics pedagogy, this project affords students a simple magnetism/geodesy field experiment requiring only a good compass and a GPS receiver with memory and a data port. The novel and straightforward data analysis with VG software yields reliable experimental values for an important abstract geophysical quantity, magnetic declination. Just as the compass has long provided

  11. A straightness error measurement method matched new generation GPS

    International Nuclear Information System (INIS)

    Zhang, X B; Lu, H; Jiang, X Q; Li, Z

    2005-01-01

    The axis of the non-diffracting beam produced by an axicon is very stable and can be adopted as the datum line to measure the spatial straightness error in continuous working distance, which may be short, medium or long. Though combining the non-diffracting beam datum-line with LVDT displace detector, a new straightness error measurement method is developed. Because the non-diffracting beam datum-line amends the straightness error gauged by LVDT, the straightness error is reliable and this method is matchs new generation GPS

  12. Analysis of Regional GPS Networks in Eastern Ontario

    Science.gov (United States)

    Samadi Alinia, H.; Tiampo, K. F.

    2014-12-01

    Although stable, intraplate region of eastern Canada is considered low rate deformation area in the North American plate, the retreat of large ice sheets during deglaciation in the last 20 ka has resulted in horizontal and vertical deformation of the Earth's in eastern Ontario. Present-day glacial isostatic adjustment (GIA) uplift rates approach 10 mm/yr or more at Hudson Bay and decrease with distance southeastward. Current GIA models forecast that the hinge line between uplift to the northwest and subsidence to the southeast lies somewhere near the Saint Lawrence valley in eastern Canada [Tushingham and Peltier, 1991; Peltier, 2002]. Employing continuous Global Positioning System (cGPS) observations and high precision tools for processing and then analyzing each component of derived time series are important tools to monitor the associated regional crustal deformation with good accuracies. Here we describe the analysis of coordinate time series of cGPS stations scattered sparsely throughout southeastern Ontario and between Ottawa and the east coast of Hudson Bay. Here, the two most reliable local networks, each including 4 to 6 reference stations, were selected for analysis. Data for period of approximately five years, 2008-2012.9, was processed with Bernese 5.0 over several campaigns. Individual cGPS coordinate time series were generated for each station and basic parameters, such as mean, variance and repeatability, were estimated. The time series are corrected with respect to the rigid plate motion and seasonal variations and advanced time series analysis techniques, including spectral analysis and principal component analysis were implemented. Post-processing of the time series reproduces the general GIA spatial pattern. Results also show that the vertical velocities of all stations in the solution are consistent with the GIA model uplift rate and are consistent with other cGPS sites in eastern Canada and increases from north of lake of Ontario (approximately

  13. GPS and Galileo: Friendly Foes? (Walker Paper, Number 12)

    Science.gov (United States)

    2008-05-01

    their data, others employ different techniques. US defense contractor Lockheed Martin developed an anti-jam GPS receiver in 2000 for its joint air...26. Jolis , “Problems Run Rampant for Galileo Project.” 27. Ibid. 28. “Galileo, Involving Europe,” 23. 29. Ibid., 16. 30. Ibid., 17. Assuming that by...Told to Put House in Order.” 38. EC, “Galileo, Involving Europe,” 5. 39. “Galileo Adrift in European Outer Space.” 40. Jolis , “Problems Run Rampant

  14. Navigation GPS/GLONASS in the Arctic and aurora

    Directory of Open Access Journals (Sweden)

    Chernouss S. A.

    2016-12-01

    Full Text Available The correspondence of the time-spatial distribution of the radiances of the aurora oval and time-spatial changes in the parameters of the navigation satellites' signal has been shown. For this aim the experimental data on the regional and local heterogeneities of the Total Electron Content (or TEC and the data on the signal delays in the polar ionosphere have been analyzed. Using the data concerning aurora as the indicator of disturbances in the work of the GPS/GLONASS systems can give the opportunity to increase considerably the accuracy of positioning in the Arctic with the help of satellite navigation systems (SNS.

  15. G.P.S. Occhialini 1907-93

    International Nuclear Information System (INIS)

    Peyrou, C.

    1994-01-01

    G.P.S. Occhialini, a legendary figure for all who remember the very beginnings of cosmic ray particle physics, died on 30 December. Born on 5 December 1907 in Rossombrone, near Urbino, he studied in Florence. Here he met Bruno Rossi, whom, although only two years his senior, he always regarded as a master. In 1932 Occhialini went to Cambridge where he worked with P.M.S. Blackett. They invented and perfected the counter-triggered Wilson chamber technique, recording cascade showers which confirmed the existence of the positron, discovered slightly earlier by Anderson, and demonstrating its symmetry with the electron

  16. GPS Navigation for the Magnetospheric Multi-Scale Mission

    Science.gov (United States)

    Bamford, William; Mitchell, Jason; Southward, Michael; Baldwin, Philip; Winternitz, Luke; Heckler, Gregory; Kurichh, Rishi; Sirotzky, Steve

    2009-01-01

    In 2014. NASA is scheduled to launch the Magnetospheric Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the Earth's magnetosphere. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter

  17. Evaluating the performance of a low-cost GPS in precision agriculture applications

    DEFF Research Database (Denmark)

    Jensen, Kjeld; Larsen, Morten; Simonsen, Tom

    2012-01-01

    Field Robots are often equipped with a Real Time Kinematic (RTK) GPS to obtain precise positioning. In many precision agriculture applications, however, the robot operates in semi-structured environments like orchards and row crops, where local sensors such as computer vision and laser range...... scanners can produce accurate positioning relative to the crops. GPS is then primarily needed for robust inter-row navigation. This work evaluates a new low-cost GPS. Static tests were used to test the absolute accuracy. To test the GPS in a precision agriculture environment it was installed on a robot...

  18. The lesser evil? Initiating a benzodiazepine prescription in general practice: a qualitative study on GPs' perspectives.

    Science.gov (United States)

    Anthierens, Sibyl; Habraken, Hilde; Petrovic, Mirko; Christiaens, Thierry

    2007-12-01

    Chronic benzodiazepine (BZD) use is widespread and linked with adverse effects. There is consensus concerning the importance of initiating BZD as a crucial moment. Nevertheless specific research in this field is lacking. This paper addresses the views of GPs on why they start prescribing BZDs to first-time users. Qualitative study with five focus groups analysed using a systematic content analysis. Regions of Ghent and Brussels in Belgium. A total of 35 general practitioners. The GPs' perspective on their initiating of BZD prescribing. GPs reported that they are cautious in initiating BZD usage. At the same time, GPs feel overwhelmed by the psychosocial problems of their patients. They show empathy by prescribing. They feel in certain situations there are no other solutions and they experience BZDs as the lesser evil. They admit to resorting to BZDs because of time restraint and lack of alternatives. GPs do not perceive the addictive nature of BZD consumption as a problem with first-time users. GPs do not specifically mention patients' demand as an element for starting. The main concern of GPs is to help the patient. GPs should be aware of the addictive nature of BZD even in low doses and a non-pharmacological approach should be seen as the best first approach. If GPs decide to prescribe a BZD they should make plain to the patient that the medication is only a "temporary" solution with clear agreements with regard to medication withdrawal.

  19. Deformation analysis of Aceh April 11{sup th} 2012 earthquake using GPS observation data

    Energy Technology Data Exchange (ETDEWEB)

    Maulida, Putra, E-mail: putra.maulida@gmail.com [Bandung Institute of Technology (ITB), Jalan Ganesha 10, Bandung 40132 (Indonesia); Meilano, Irwan; Sarsito, Dina A. [Bandung Institute of Technology (ITB), Jalan Ganesha 10, Bandung 40132 (Indonesia); Geodesy Research Group, geodesy and geomatic Engineering, ITB (Indonesia); Susilo [Bandung Institute of Technology (ITB), Jalan Ganesha 10, Bandung 40132 (Indonesia); Geospatial Information Agency (BIG) (Indonesia)

    2015-04-24

    This research tries to estimate the co-seismic deformation of intraplate earthquake occurred off northern Sumatra coast which is about 100-200 km southwest of Sumatrasubduction zone. The earthquake mechanism was strike-slip with magnitude 8.6 and triggering aftershock with magnitude 8.2 two hours later. We estimated the co-seismic deformation by using the GPS (Global Positioning System) continuous data along western Sumatra coast. The GPS observation derived from Sumatran GPS Array (SuGAr) and Geospatial Information Agency (BIG). For data processing we used GPS Analyze at Massachusetts Institute of Technology (GAMIT) software and Global Kalman Filter (GLOBK) to estimate the co-seismic deformation. From the GPS daily solution, the result shows that the earthquake caused displacement for the GPS stations in Sumatra. GPS stations in northern Sumatra showed the displacement to the northeast with the average displacement was 15 cm. The biggest displacement was found at station BSIM which is located at Simeuleu Island off north west Sumatra coast. GPS station in middle part of Sumatra, the displacement was northwest. The earthquake also caused subsidence for stations in northern Sumatra, but from the time series there was not sign of subsidence was found at middle part of Sumatra. In addition, the effect of the earthquake was worldwide and affected the other GPS Stations around Hindia oceanic.

  20. Are part timers real GPs? Attitudes of general practitioners toward those who work part time.

    Science.gov (United States)

    Mazza, D; Northfield, S

    2000-09-01

    Current attitudes within the medical profession suggest that one cannot be a 'real' doctor unless one works full time. The aim of this study was to determine the views and attitudes of a sample of GPs toward part time practice. As part of a larger study, GPs in two divisions in metropolitan Melbourne were sent a questionnaire based survey. GPs were asked to rate statements about part time practice using a Likert scale. The response rate was 55% (n = 246). The majority of GPs disagreed with the statement 'part time GPs are not real GPs' but feelings were mixed about whether part timers covered the same range of clinical content as full timers. One fifth of respondents questioned the competence of part time GPs. Male GPs, those over 55 years and full timers were more likely to hold negative views toward part time general practice. Our results show a 'generational' pattern toward part time practice. With the increasing numbers of women entering general practice, these attitudes will need to change to accommodate the fact that more GPs will be choosing to work part time in the future.

  1. Data Integration from GPS and Inertial Navigation Systems for Pedestrians in Urban Area

    Directory of Open Access Journals (Sweden)

    Krzysztof Bikonis

    2013-09-01

    Full Text Available The GPS system is widely used in navigation and the GPS receiver can offer long-term stable absolute positioning information. The overall system performance depends largely on the signal environments. The position obtained from GPS is often degraded due to obstruction and multipath effect caused by buildings, city infrastructure and vegetation, whereas, the current performance achieved by inertial navigation systems (INS is still relatively poor due to the large inertial sensor errors. The complementary features of GPS and INS are the main reasons why integrated GPS/INS systems are becoming increasingly popular. GPS/INS systems offer a high data rate, high accuracy position and orientation that can work in all environments, particularly those where satellite availability is restricted. In the paper integration algorithm of GPS and INS systems data for pedestrians in urban area is presented. For data integration an Extended Kalman Filter (EKF algorithm is proposed. Complementary characteristics of GPS and INS with EKF can overcome the problem of huge INS drifts, GPS outages, dense multipath effect and other individual problems associated with these sensors.

  2. An Advanced Data Warehouse for Integrating Large Sets of GPS Data

    DEFF Research Database (Denmark)

    Andersen, Ove; Krogh, Benjamin Bjerre; Thomsen, Christian

    2014-01-01

    GPS data recorded from driving vehicles is available from many sources and is a very good data foundation for answering traffic related queries. However, most approaches so far have not considered combining GPS data from many sources into a single data warehouse. Further, the integration of GPS...... data with fuel consumption data (from the so-called CAN bus in the vehicles) and weather data has not been done. In this paper, we propose a data warehouse design for handling GPS data, fuel consumption data, and weather data. The design is fully implemented in a running system using the Postgre...

  3. GPs' attitudes, beliefs and behaviours regarding exercise for chronic knee pain: a questionnaire survey

    Science.gov (United States)

    Foster, Nadine E; Porcheret, Mark; Rathod, Trishna; Roddy, Edward

    2017-01-01

    Objectives The aim of this study was to investigate general practitioners’ (GPs) attitudes, beliefs and behaviours regarding the use of exercise for patients with chronic knee pain (CKP) attributable to osteoarthritis. Setting Primary care GPs in the UK. Participants 5000 GPs, randomly selected from Binley’s database, were mailed a cross-sectional questionnaire survey. Outcome measures GPs’ attitudes and beliefs were investigated using attitude statements, and reported behaviours were identified using vignette-based questions. GPs were invited to report barriers experienced when initiating exercise with patients with CKP Results 835 (17%) GPs responded. Overall, GPs were positive about general exercise for CKP. 729 (87%) reported using exercise, of which, 538 (74%) reported that they would use both general and local (lower limb) exercises. However, only 92 (11% of all responding) GPs reported initiating exercise in ways aligning with best-evidence recommendations. 815 (98%) GPs reported barriers in using exercise for patients with CKP, most commonly, insufficient time in consultations (n=419; 51%) and insufficient expertise (n=337; 41%). Conclusions While GPs’ attitudes and beliefs regarding exercise for CKP were generally positive, initiation of exercise was often poorly aligned with current recommendations, and barriers and uncertainties were reported. GPs’ use of exercise may be improved by addressing the key barriers of time and expertise, by developing a pragmatic approach that supports GPs to initiate individualised exercise, and/or by other professionals taking on this role. PMID:28624759

  4. The role of GPs in increasing compliance to colorectal cancer screening: a randomised controlled trial (Italy).

    Science.gov (United States)

    Federici, Antonio; Giorgi Rossi, Paolo; Bartolozzi, Francesco; Farchi, Sara; Borgia, Piero; Guastcchi, Gabriella

    2006-02-01

    To assess the effect of the provider (GPs versus hospital) on the compliance in returning the faecal occult blood test. To analyse the characteristics of the GP associated with high compliance among his beneficiaries. A questionnaire about screening attitudes was mailed to the 1192 GPs working in 13 districts of the Lazio region. We asked the GPs to participate in a randomised trial, we sampled 130 GPs and about 1/10 of the GPs' 50-75 year old beneficiaries (n = 3657) were invited to be screened at the GP office and 1/10 (3675) at the nearest gastroenterology centre. 58.5% of the GPs completed the questionnaire and 22.7% agreed to participate in the trial. The compliance in the GP arm was 50%, in the hospital arm 16% (RR 3.4; 95% CI: 3.13-3.70). There was a high variability in the compliance obtained by the GPs. GPs with more than 25 patients visited/day and those incorrectly recommended screening of colorectal cancer obtained a lower compliance (OR 0.74, 95% CI: 0.57-0.95 and OR 0.76, 95% CI: 0.59-0.97, respectively). The involvement of GPs in colorectal cancer screening can be very effective to enhance the compliance, but the effectiveness is dependent on their willingness to be involved.

  5. Deformation analysis of Aceh April 11th 2012 earthquake using GPS observation data

    Science.gov (United States)

    Maulida, Putra; Meilano, Irwan; Sarsito, Dina A.; Susilo

    2015-04-01

    This research tries to estimate the co-seismic deformation of intraplate earthquake occurred off northern Sumatra coast which is about 100-200 km southwest of Sumatrasubduction zone. The earthquake mechanism was strike-slip with magnitude 8.6 and triggering aftershock with magnitude 8.2 two hours later. We estimated the co-seismic deformation by using the GPS (Global Positioning System) continuous data along western Sumatra coast. The GPS observation derived from Sumatran GPS Array (SuGAr) and Geospatial Information Agency (BIG). For data processing we used GPS Analyze at Massachusetts Institute of Technology (GAMIT) software and Global Kalman Filter (GLOBK) to estimate the co-seismic deformation. From the GPS daily solution, the result shows that the earthquake caused displacement for the GPS stations in Sumatra. GPS stations in northern Sumatra showed the displacement to the northeast with the average displacement was 15 cm. The biggest displacement was found at station BSIM which is located at Simeuleu Island off north west Sumatra coast. GPS station in middle part of Sumatra, the displacement was northwest. The earthquake also caused subsidence for stations in northern Sumatra, but from the time series there was not sign of subsidence was found at middle part of Sumatra. In addition, the effect of the earthquake was worldwide and affected the other GPS Stations around Hindia oceanic.

  6. Sistema de Posicionamiento para Vehículos Autónomos

    Directory of Open Access Journals (Sweden)

    V. Milanés

    2008-10-01

    Full Text Available Resumen: Uno de los objetivos más importantes de los Sistemas Inteligentes de Transporte (ITS es evitar la pérdida de precisión en el posicionamiento y guiado del vehículo, debido a la disminución en la calidad de la señal del Sistema de Posicionamiento Global (GPS. En este artículo, se presenta un sistema de posicionamiento formado por la combinación de un GPS con una unidad de medida inercial ayudada por los sensores embarcados en el coche para realizar el guiado. En función de la precisión proporcionada por el GPS, el sistema discrimina entre tres posibles comportamientos: 1 Si la precisión es centimétrica, el GPS se encarga en solitario del guiado. 2 Si no se recibe la señal GPS, el control lo toma la unidad inercial. 3 Si la precisión de la señal del GPS no es centimétrica, la posición del vehículo se calcula mediante una combinación de ambas medidas. El sistema se ha instalado en un Citroën C3 Pluriel. Los resultados muestran un correcto comportamiento del vehículo en diferentes situaciones y prueban la necesidad de integrar la información sensorial para realizar un control de navegación óptimo. Palabras Clave: guiado automatizado de vehículos, sistemas de posicionamiento global, unidad de medida inercial

  7. Sistema para el Seguimiento del funcionamiento de ecosistemas en la Red de Parques Nacionales de España mediante Teledetección

    Directory of Open Access Journals (Sweden)

    J. Cabello

    2016-06-01

    Full Text Available La gestión de las áreas protegidas en el actual contexto de cambio global requiere de aproximaciones que permitan caracterizar y seguir el funcionamiento de los ecosistemas. La teledetección ofrece herramientas para ello, ya que proporciona índices que informan reiteradamente y para grandes porciones de territorio, de los intercambios de materia y energía que tienen lugar entre la biota y la superficie terrestre. Considerando este principio, y la cada vez mayor disponibilidad de información satelital de calidad y facilidad de uso, desarrollamos junto con el Organismo Autónomo de Parques Nacionales de España (OAPN, un sistema de seguimiento que complementa a otras iniciativas desarrolladas por este organismo para informar del estado de conservación de los parques nacionales. El sistema, denominado REMOTE, se basa en el empleo de los índices de vegetación espectrales (IVs de uso más extendido (EVI -índice de vegetación mejorado- y NDVI -índice de vegetación normalizado-, derivados de la serie temporal de imágenes satelitales del sensor MODIS-Terra. El sistema permite avanzar en la identificación de las condiciones de referencia para la comprensión y predicción de las respuestas de los ecosistemas frente a perturbaciones e intervenciones, y de los cambios direccionales que éstos están experimentando (tendencias. Así mismo ayuda a la detección de anomalías recientes que alertan de cambios bruscos en el funcionamiento de los ecosistemas. REMOTE se caracteriza porque usa como indicadores tres atributos relacionados con las ganancias de carbono anuales (productividad primaria neta por parte del dosel vegetal, su estacionalidad y fenología. Además, está diseñado y programado con software libre y gratuito, lo que permitirá modificar o implementar mejoras en él fácilmente. Su implementación tiene como objetivo informar a los tomadores de decisiones y gestores de la Red de Parques Nacionales de España de la salud y estado

  8. GPS-based Microenvironment Tracker (MicroTrac) Model to ...

    Science.gov (United States)

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure to do so can add uncertainty and bias to risk estimates. In this study, a classification model, called MicroTrac, was developed to estimate time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from global positioning system (GPS) data and geocoded building boundaries. Based on a panel study, MicroTrac estimates were compared to 24 h diary data from 7 participants on workdays and 2 participants on nonworkdays, with corresponding GPS data and building boundaries of home, school, and work. MicroTrac correctly classified the ME for 99.5% of the daily time spent by the participants. The capability of MicroTrac could help to reduce the time-location uncertainty in air pollution exposure models and exposure metrics for individuals in health studies. The National Exposure Research Laboratory’s (NERL’s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA’s mission to protect human health and the environment. HEASD’s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA’s strategic plan. More specifically, our division conducts research to characterize

  9. Updating Road Networks by Local Renewal from GPS Trajectories

    Directory of Open Access Journals (Sweden)

    Tao Wu

    2016-09-01

    Full Text Available The long production cycle and huge cost of collecting road network data often leave the data lagging behind the latest real conditions. However, this situation is rapidly changing as the positioning techniques ubiquitously used in mobile devices are gradually being implemented in road network research and applications. Currently, the predominant approaches infer road networks from mobile location information (e.g., GPS trajectory data directly using various extracting algorithms, which leads to expensive consumption of computational resources in the case of large-scale areas. For this reason, we propose an alternative that renews road networks with a novel spiral strategy, including a hidden Markov model (HMM for detecting potential problems in existing road network data and a method to update the data, on the local scale, by generating new road segments from trajectory data. The proposed approach reduces computation costs on roads with completed or updated information by updating problem road segments in the minimum range of the road network. We evaluated the performance of our proposals using GPS traces collected from taxies and OpenStreetMap (OSM road networks covering urban areas of Wuhan City.

  10. Habitat Selection and Activity Pattern of GPS Collared Sumateran Tigers

    Directory of Open Access Journals (Sweden)

    Dolly Priatna

    2012-12-01

    Full Text Available Although translocation has been used in mitigating human-carnivore conflict for decades, few studies have been conducted on the behavioral ecology of released animals. Such information is necessary in the context of sustainable forest management. In this study we determine the type of land cover used as main habitat and examine the activity pattern of translocated tigers. Between 2008 and 2010 we captured six conflict tigers and translocated them 74-1,350 km from their capture sites in Sumatera. All tigers were fitted with global positioning system (GPS collars. The collars were set to fix 24-48 location coordinates per day.  All translocated tigers showed a preference for a certain habitat type within their new home range, and tended to select the majority of natural land cover type within the landscape as their main habitat, but the availability of natural forest habitat within the landscape remains essensial for their survival. The activity of male translocated tigers differed significantly between the six time intervals of 24 hours, and their most active periods were in the afternoon (14:00-18:00 hours and in the evening (18:00-22:00 hours. Despite being preliminary, the findings of this study-which was the first such study conducted in Sumatera-highlight the conservation value of tiger translocation and provide valuable information for improving future management of conflict tigers.Keywords: activity pattern, GPS collars, habitat selection, sumateran tiger, translocation

  11. Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements

    Science.gov (United States)

    Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.

    2011-01-01

    Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background TEC value. Observations near the epicenter are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.

  12. Atmospheric density determination using high-accuracy satellite GPS data

    Science.gov (United States)

    Tingling, R.; Miao, J.; Liu, S.

    2017-12-01

    Atmospheric drag is the main error source in the orbit determination and prediction of low Earth orbit (LEO) satellites, however, empirical models which are used to account for atmosphere often exhibit density errors around 15 30%. Atmospheric density determination thus become an important topic for atmospheric researchers. Based on the relation between atmospheric drag force and the decay of orbit semi-major axis, we derived atmospheric density along the trajectory of CHAMP with its Rapid Science Orbit (RSO) data. Three primary parameters are calculated, including the ratio of cross sectional area to mass, drag coefficient, and the decay of semi-major axis caused by atmospheric drag. We also analyzed the source of error and made a comparison between GPS-derived and reference density. Result on 2 Dec 2008 shows that the mean error of GPS-derived density can decrease from 29.21% to 9.20% when time span adopted on the process of computation increase from 10min to 50min. Result for the whole December indicates that when the time span meet the condition that the amplitude of the decay of semi-major axis is much greater than its standard deviation, then density precision of 10% can be achieved.

  13. Methodology for Calculating Latency of GPS Probe Data

    Energy Technology Data Exchange (ETDEWEB)

    Young, Stanley E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wang, Zhongxiang [University of Maryland; Hamedi, Masoud [University of Maryland

    2017-10-01

    Crowdsourced GPS probe data, such as travel time on changeable-message signs and incident detection, have been gaining popularity in recent years as a source for real-time traffic information to driver operations and transportation systems management and operations. Efforts have been made to evaluate the quality of such data from different perspectives. Although such crowdsourced data are already in widespread use in many states, particularly the high traffic areas on the Eastern seaboard, concerns about latency - the time between traffic being perturbed as a result of an incident and reflection of the disturbance in the outsourced data feed - have escalated in importance. Latency is critical for the accuracy of real-time operations, emergency response, and traveler information systems. This paper offers a methodology for measuring probe data latency regarding a selected reference source. Although Bluetooth reidentification data are used as the reference source, the methodology can be applied to any other ground truth data source of choice. The core of the methodology is an algorithm for maximum pattern matching that works with three fitness objectives. To test the methodology, sample field reference data were collected on multiple freeway segments for a 2-week period by using portable Bluetooth sensors as ground truth. Equivalent GPS probe data were obtained from a private vendor, and their latency was evaluated. Latency at different times of the day, impact of road segmentation scheme on latency, and sensitivity of the latency to both speed-slowdown and recovery-from-slowdown episodes are also discussed.

  14. Tectonic Model of Bali Island Inferred from GPS Data

    Directory of Open Access Journals (Sweden)

    Cecep Sulaeman

    2018-01-01

    Full Text Available DOI: 10.17014/ijog.5.1.81-91Seven periods of GPS campaign have been conducted for three years since March 2013 - October 2015 on fourteen GPS sites across Bali Island. The GAMIT/GLOBK 10.6 version was used to compute data with respect for thirteen reference sites of International Terrestrial Reference Frame (ITRF 2008 surrounding Bali. The result shows that horizontal displacement varies between 1.93 and 22.53 mm/yr dominantly northeastward. Vertical displacement ranges at -184.34 to 33.79 mm/yr. The result of modeling using Coulomb 3.3 version indicates the deformation in Bali was mostly contributed by subduction at the southern part, West and East Flores Back-Arc Thrust at the north, Lombok Strait Fault and a fault at the eastern coast of Bali with the estimation maximum magnitude of 7.1, 6.6, 6.8, 5.8, and 5.2, respectively.

  15. Newly velocity field of Sulawesi Island from GPS observation

    Science.gov (United States)

    Sarsito, D. A.; Susilo, Simons, W. J. F.; Abidin, H. Z.; Sapiie, B.; Triyoso, W.; Andreas, H.

    2017-07-01

    Sulawesi microplate Island is located at famous triple junction area of the Eurasian, India-Australian, and Philippine Sea plates. Under the influence of the northward moving Australian plate and the westward motion of the Philippine plate, the island at Eastern part of Indonesia is collide and with the Eurasian plate and Sunda Block. Those recent microplate tectonic motions can be quantitatively determine by GNSS-GPS measurement. We use combine GNSS-GPS observation types (campaign type and continuous type) from 1997 to 2015 to derive newly velocity field of the area. Several strategies are applied and tested to get the optimum result, and finally we choose regional strategy to reduce error propagation contribution from global multi baseline processing using GAMIT/GLOBK 10.5. Velocity field are analyzed in global reference frame ITRF 2008 and local reference frame by fixing with respect alternatively to Eurasian plate - Sunda block, India-Australian plate and Philippine Sea plates. Newly results show dense distribution of velocity field. This information is useful for tectonic deformation studying in geospatial era.

  16. SLR and GPS spatial techniques in ITRF. Argentine results.

    Science.gov (United States)

    Actis, Eloy Vicente; Huang, Dongping; Márquez, Raúl; Adarvez, Sonia; Flores, Matías; Brizuela, Diego; Nievas, Jesica; Podestá, Ricardo; Pacheco, Ana M.; Rojas, Hernán Alvis; Yin, Zhiqiang; Li, Jinzeng; Han, Yanben; Liu, Weidong; Wang, Rui

    2012-08-01

    Along the late 30 years spatial geodetic techniques enable us to measure horizontal and vertical deformations of the Earth’s surface with a very high precision. Performing this task we made Satellite Laser Ranging (SLR), and Global Positioning System (GPS) observations in South America ILRS 7406 Station placed at Observatorio Astronómico Félix Aguilar (OAFA) in San Juan, Argentina, accomplishing a Cooperation Agreement between CAS - NAOC and OAFA - UNSJ. Trough LAGEOS II Satellite observations we obtain rectangular coordinates of San Juan ILRS Station in the Terrestrial Reference Frame (ITR 2000), standing out that Argentine Station data were included in the late arrangements ITRF given by International Earth Rotation and Reference System Service (IERS). Spatial and temporary variations of the epoch 2010 - 2011 were evaluated finding out remarkable displacements, of about a half meter, related with seismic events on the region. We confirm these deformations by means of GP S determinations referred to Permanent GPS Station placed nearby the SLR Station.

  17. Uncovering urban human mobility from large scale taxi GPS data

    Science.gov (United States)

    Tang, Jinjun; Liu, Fang; Wang, Yinhai; Wang, Hua

    2015-11-01

    Taxi GPS trajectories data contain massive spatial and temporal information of urban human activity and mobility. Taking taxi as mobile sensors, the information derived from taxi trips benefits the city and transportation planning. The original data used in study are collected from more than 1100 taxi drivers in Harbin city. We firstly divide the city area into 400 different transportation districts and analyze the origin and destination distribution in urban area on weekday and weekend. The Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm is used to cluster pick-up and drop-off locations. Furthermore, four spatial interaction models are calibrated and compared based on trajectories in shopping center of Harbin city to study the pick-up location searching behavior. By extracting taxi trips from GPS data, travel distance, time and average speed in occupied and non-occupied status are then used to investigate human mobility. Finally, we use observed OD matrix of center area in Harbin city to model the traffic distribution patterns based on entropy-maximizing method, and the estimation performance verify its effectiveness in case study.

  18. Factors influencing recording of drug misuse in primary care: a qualitative study of GPs in England.

    Science.gov (United States)

    Davies-Kershaw, Hilary; Petersen, Irene; Nazareth, Irwin; Stevenson, Fiona

    2018-04-01

    Drug misuse is a serious public health problem. Evidence from previous epidemiological studies show that GPs are recording drug misuse in electronic patient records (EPR). However, although the recording trends are similar to national surveys, recording rates are much lower. To explore the factors that influence GPs to record drug misuse in the EPR, and to gain a clearer understanding of the gap between the amount of drug misuse recorded in primary care and that in national surveys and other studies. A semi-structured qualitative interview study of GPs working in general practices across England. Purposive sampling was employed to recruit 12 GPs, both with and without a special interest in drug misuse, from across England. Semi-structured face-to-face interviews were conducted to consider whether and why GPs record drug misuse, which methods GPs use for recording, GPs' actions if a patient asks for the information not to be recorded, and GPs' actions if they think a patient misuses drugs but does not disclose the information. Resulting data were analysed using a combination of inductive and deductive thematic analysis. The complexity of asking about drug misuse preceded GPs' decision to record. They described how the context of the general practice protocols, interaction between GP and patient, and the questioning process affected whether, how, and in which circumstances they asked about drug use. This led to GPs making a clinical decision on whether, who, and how to record in the EPR. When making decisions about whether or not to record drug misuse, GPs face complex choices. Aside from their own views, they reported feelings of pressure from the general practice environment in which they worked and their clinical commissioning group, as well as government policies. © British Journal of General Practice 2018.

  19. A Forward GPS Multipath Simulator Based on the Vegetation Radiative Transfer Equation Model.

    Science.gov (United States)

    Wu, Xuerui; Jin, Shuanggen; Xia, Junming

    2017-06-05

    Global Navigation Satellite Systems (GNSS) have been widely used in navigation, positioning and timing. Nowadays, the multipath errors may be re-utilized for the remote sensing of geophysical parameters (soil moisture, vegetation and snow depth), i.e., GPS-Multipath Reflectometry (GPS-MR). However, bistatic scattering properties and the relation between GPS observables and geophysical parameters are not clear, e.g., vegetation. In this paper, a new element on bistatic scattering properties of vegetation is incorporated into the traditional GPS-MR model. This new element is the first-order radiative transfer equation model. The new forward GPS multipath simulator is able to explicitly link the vegetation parameters with GPS multipath observables (signal-to-noise-ratio (SNR), code pseudorange and carrier phase observables). The trunk layer and its corresponding scattering mechanisms are ignored since GPS-MR is not suitable for high forest monitoring due to the coherence of direct and reflected signals. Based on this new model, the developed simulator can present how the GPS signals (L1 and L2 carrier frequencies, C/A, P(Y) and L2C modulations) are transmitted (scattered and absorbed) through vegetation medium and received by GPS receivers. Simulation results show that the wheat will decrease the amplitudes of GPS multipath observables (SNR, phase and code), if we increase the vegetation moisture contents or the scatters sizes (stem or leaf). Although the Specular-Ground component dominates the total specular scattering, vegetation covered ground soil moisture has almost no effects on the final multipath signatures. Our simulated results are consistent with previous results for environmental parameter detections by GPS-MR.

  20. Seeing through the glass darkly? A qualitative exploration of GPs' drinking and their alcohol intervention practices.

    Science.gov (United States)

    Kaner, Eileen; Rapley, Tim; May, Carl

    2006-08-01

    Brief alcohol intervention is influenced by patients' personal characteristics as well as their clinical risk. Risk-drinkers from higher social-status groups are less likely to receive brief intervention from GPs than those from lower social-status groups. Thus GPs' perception of social similarity or distance may influence brief intervention. To explore the role that GPs' drinking behaviour plays in their recognition of alcohol-related risk in patients. A qualitative interview study with 29 GPs recruited according to maximum variation sampling. All interviews were audio-recorded and transcribed verbatim. Analysis was inductive with constant comparison within and between themes plus deviant case analysis. Analysis developed until category saturation was reached. GPs described a range of personal drinking practices that broadly mirrored population drinking patterns. Many saw themselves as part of mainstream society, sharing in culturally sanctioned behaviour. For some GPs, shared drinking practices could increase empathy for patients who drank, and facilitate discussion about alcohol. However, several GPs regarded themselves as distinct from 'others', separating their own drinking from that of patients. Several GPs described a form of bench-marking, wherein only patients who drank more, or differently, to themselves were felt to be 'at risk'. Alcohol is clearly a complex and emotive health and social issue and GPs are not immune to its effects. For some GPs' shared drinking behaviour can act as a window of opportunity enabling insight on alcohol issues and facilitating discussion. However, other GPs may see through the glass more darkly and selectively recognize risk only in those patients who are least like them.

  1. Design of complete software GPS signal simulator with low complexity and precise multipath channel model

    Directory of Open Access Journals (Sweden)

    G. Arul Elango

    2016-09-01

    Full Text Available The need for GPS data simulators have become important due to the tremendous growth in the design of versatile GPS receivers. Commercial hardware and software based GPS simulators are expensive and time consuming. In this work, a low cost simple novel GPS L1 signal simulator is designed for testing and evaluating the performance of software GPS receiver in a laboratory environment. A typical real time paradigm, similar to actual satellite derived GPS signal is created on a computer generated scenario. In this paper, a GPS software simulator is proposed that may offer a lot of analysis and testing flexibility to the researchers and developers as it is totally software based primarily running on a laptop/personal computer without the requirement of any hardware. The proposed GPS simulator allows provision for re-configurability and test repeatability and is developed in VC++ platform to minimize the simulation time. It also incorporates Rayleigh multipath channel fading model under non-line of sight (NLOS conditions. In this work, to efficiently design the simulator, several Rayleigh fading models viz. Inverse Discrete Fourier Transform (IDFT, Filtering White Gaussian Noise (FWFN and modified Sum of Sinusoidal (SOS simulators are tested and compared in terms of accuracy of its first and second order statistical metrics, execution time and the later one is found to be as the best appropriate Rayleigh multipath model suitable for incorporating with GPS simulator. The fading model written in ‘MATLAB’ engine has been linked with software GPS simulator module enable to test GPS receiver’s functionality in different fading environments.

  2. Evaluation on the performance of single and dual frequency low cost GPS module observation using geodetic antenna

    Directory of Open Access Journals (Sweden)

    Dedi Atunggal

    2018-06-01

    Full Text Available GPS modules have been used for various applications in recent years. Its early development came in parallel with the advancement of Unmanned Aerial Vehicle (UAV technology. Nowadays, it is also used in in geographic information system (GIS data acquisition/census, mapping surveys, structure stability monitoring systems and many other applications. GPS modules generally have several positioning features, including standard positioning service (SPS, static positioning, precise point positioning (PPP, post processing kinematic (PPK and real time kinematic (RTK GPS. GPS modules in general are only equipped with a microstrip-type antenna or better known as patch antenna. Results from related research show that GPS module with this type of antenna has sub meter accuracy when used for PPK or RTK GPS method. The use of geodetic antennas is very potential to increase GPS position accuracy by up to centimeter level. This paper discusses the evaluation of GPS module measurements with geodetic type antennas for precise positioning using RTK GPS. This paper is focused on the resolution of GPS cycle ambiguity that is often expressed by the term fixing ratio and the accuracy of measurement results obtained. To provide a comprehensive description of the performance of GPS module, in this research two types of GPS module were used; single and dual frequency. Both types of GPS modules were used to conduct simultaneous observation on an open and obstructed observation location.

  3. Resultados del uso de geodesia satelital para estudios geodinámicos en Colombia

    Directory of Open Access Journals (Sweden)

    Mora-Páez Hector

    2002-08-01

    Full Text Available

    The use of GPS technology provides direct measurements of displacements due to plate motions and intraplate deformation, basic information for understanding kinematic of the movements. Using satelital geodesy techniques, crustal deformation rates in the southwestern Caribbean, southeastern of Central America and northwestern of South America wide plate boundary have been derived from GPS campaigns in 1988, 1990, 1991, 1994, 1996 and 1998 as part of the CASA (Central And South America GPS Project. The zone of study includes the area of complex interaction between the Caribbean, Nazca and South America plates. The same GPS stations have been occupied with the purpose of making comparisons on the position of each site, analyzing distances of separation (baselines and obtaining displacement vectors (magnitude and orientation. Some results are showed using the GIPSY -OASIS II software, that is a precision package for the analysis of GPS data developed by JPL-NASA. INGEOMINAS has built a GPS network called GEORED to be occupied succesively in order to get information about intraplate deformation, under the institutional project named Survey, Compilation and Generation of Geodynamics Information.

    EI uso de la tecnología GPS provee mediciones directas de los desplazamientos debido al movimiento de las placas y la deformación intraplaca, información básica para el entendimiento de la cinemática de los movimientos, Empleando técnicas de geodesia satelital, tasas de deformación de corteza terrestre en el límite amplio de placas al suroeste del Caribe, sureste de América Central y noroeste de Suramérica han sido

  4. 47 CFR 87.151 - Special requirements for differential GPS receivers.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Special requirements for differential GPS receivers. 87.151 Section 87.151 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... differential GPS receivers. (a) The receiver shall achieve a message failure rate less than or equal to one...

  5. Characterizing the spatial and temporal activities of free-ranging cows from GPS data

    Science.gov (United States)

    Electronic tracking provides a unique way to document animal behavior on a continuous basis. This manuscript describes how uncorrected 1 s GPS fixes can be used to characterize the rate of cow travel (m·s-1) into stationary, foraging and walking activities. Cows instrumented with GPS devices were ...

  6. 77 FR 16860 - Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of...

    Science.gov (United States)

    2012-03-22

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-783] Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of Investigation on the Basis of Settlement AGENCY: U.S... GPS navigation products, components thereof, and related software, by reason of the infringement of...

  7. Differences between Practice Patterns of Conventional and Naturopathic GPs in Germany.

    Science.gov (United States)

    Laux, Gunter; Musselmann, Berthold; Kiel, Marion; Szecsenyi, Joachim; Joos, Stefanie

    2016-01-01

    Limited evidence exists whether practice patterns of general practitioners (GPs) who have additionally completed training in naturopathy are different from those of conventional GPs. We aimed to assess and compare practice patterns of GPs in conventional and naturopathic GPs. Routine data from 41 GPs (31 with and 11 without additional qualification in NP, respectively) and 180,789 patients, drawn from the CONTinuous morbidity registration Epidemiologic NeTwork (CONTENT)-registry and collected between 2009 and 2014, were used. To assess practice patterns determinants of (non-)phytopharmaceutical prescriptions, referrals and hospitalizations were analyzed using mixed-effects Poisson regression models. As explanatory variables, the qualification of the GP in NM, the age group and sex of the patient, as well as bivariate interactions between these variables were considered. GPs additionally qualified in naturopathy exhibited higher rates of phytopharmaceutical prescriptions (pGPs. This association was not observed with respect to non-phytopharmaceutical prescriptions. However, interaction effects between qualification and age group as well as sex were present with respect to both phytopharmaceutical and non-phytopharmaceutical prescriptions (all pGPs could be subject to certain age groups and sex. However, the magnitude of these differences seem to be rather small.

  8. Error detection in GPS observations by means of Multi-process models

    DEFF Research Database (Denmark)

    Thomsen, Henrik F.

    2001-01-01

    The main purpose of this article is to present the idea of using Multi-process models as a method of detecting errors in GPS observations. The theory behind Multi-process models, and double differenced phase observations in GPS is presented shortly. It is shown how to model cycle slips in the Mul...

  9. 77 FR 37660 - ICWG Meeting for the NAVSTAR GPS Public Signals in Space

    Science.gov (United States)

    2012-06-22

    ... in Space AGENCY: The United States Air Force. ACTION: Meeting Notice. SUMMARY: The Public Interface... Space (SiS) documents; IS-GPS-200 (Navigation User Interfaces), IS-GPS-705 (User Segment L5 Interfaces... resolve the comments against the public signals-in-space (SiS) documents with respect to the two issues...

  10. 75 FR 28318 - Eighty-Second Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2010-05-20

    ..., GPS/Inertial, Colson Board Room. Wednesday, June 9th All Day, Working Group 2, GPS/WAAS, Hilton-ATA...-NBAA Room & Hilton-ATA Room. Friday, June 11th Plenary Session--See Agenda Below Agenda--Plenary Session--Agenda June 11th, 2010--starting at 9 a.m. MacIntosh-NBAA & Hilton-ATA Rooms Chairman's...

  11. Estimering af bilers brændstofforbrug ved brug af eksisterende GPS data

    DEFF Research Database (Denmark)

    Andersen, Ove; Lahrmann, Harry; Torp, Kristian

    2012-01-01

    GPS data opsamles i mange sammenhænge f.eks. for at finde køretider i vejnettet. I denne artikel vises, hvorledes eksisterende GPS data kan bruges til at estimere brændstofforbruget for en tur. En metode til at estimere brændstofforbruget for en enkelt tur generaliseres til at kunne estimere...

  12. Using GPS instruments and GIS techniques in data management for insect pest control programs

    International Nuclear Information System (INIS)

    2006-01-01

    This interactive tutorial CD entitled 'Using GPS Instruments and GIS Techniques in Data Management for Insect Pest Control Programs' was developed by Micha silver of the Arava Development Co., Sapir, Israel, and includes step-by-step hands on lessons on the use of GPS/GIS in support of area-wide pest control operations

  13. Auditing GPs' prescribing habits : Cardiovascular prescribing frequently continues medication initiated by specialists

    NARCIS (Netherlands)

    de Vries, C.S; van Diepen, N.M; de Jong-van den Berg, L T W

    Objective: To determine to what extent general practitioners' (GPs) prescribing behaviour is a result of repeat prescribing of medication which has been initiated by specialists. Method: During a 4-week period, pharmacists identified GPs' prescriptions for a large group of cardiovascular drugs.

  14. Good end-of-life care according to patients and their GPs

    NARCIS (Netherlands)

    Borgsteede, Sander D.; Graafland-Riedstra, Corrie; Deliens, Luc; Francke, Anneke L.; van Eijk, Jacques ThM; Willems, Dick L.

    2006-01-01

    BACKGROUND: Most patients prefer to die at home, where a GP provides end-of-life care. A few previous studies have been directed at the GPs' values on good end-of-life care, yet no study combined values of patients and their own GP. AIM: To explore the aspects valued by both patients and GPs in

  15. Knowledge of Dutch GPs in caring for cancer patients using oral anticancer therapy at home

    NARCIS (Netherlands)

    van Roosmalen, Sanne L. C.; Pols, A. Jeannette; Willems, Dick L.

    2013-01-01

    The GP's role in cancer care is changing and will become increasingly important. One of the challenges for GPs in caring for cancer patients is their lack of specialized knowledge and the impossibility to keep up to date with developments in the field of oncology. We investigated GPs use of

  16. Feasibility study and technical proposal for long-term observations of bedrock stability with gps

    International Nuclear Information System (INIS)

    Ruizhi Chen; Kakkuri, J.

    1994-01-01

    In order to study the regional crustal deformation pattern in the territory of Finland, the Finnish Geodetic Institute is establishing the Finnish Permanent GPS Network, which is part of the Fennoscandian Permanent GPS Network. The Finnish GPS Network consists of a 12 stations located in different geological structures. The operation procedure of the network is described in the report. Feasibility study for monitoring the bedrock stability at local scale was performed. The study was carried out on the basis of an experiment on a baseline of 1041 metres. Twelve artificial movements ranging from 1 mm to 22 mm were generated with a precision-manufactured screw drive (with an accuracy of better than +-0.05 mm). The artificial movements were then detected with the GPS measurements. A preliminary analysis of the GPS data shows that the maximum difference between the GPS detected movements and the artificial movements is 0.9 mm with a standard deviation of +-0.46 mm. The observation time for reaching such accuracy is about 55 minutes. Three GPS networks were preliminarily designed for the radioactive waste disposal investigation sites of Olkiluoto, Kivetty and Romuvaara. Detailed research plan for achieving the best possible result from GPS measurements was proposed. (58 refs., 25 figs., 1 tab.)

  17. PosQ : Unsupervised Fingerprinting and Visualization of GPS Positioning Quality

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Weckemann, Kay

    2010-01-01

    GPS positioning does not provide pervasive coverage and the accuracy depends on the local environment. When deploying and managing position-based applications it is important to know when to depend on GPS and when to deploy supplementary means of positioning, such as local or inertial positioning...

  18. SMS-based time use research among Dutch GPs: an experiment.

    NARCIS (Netherlands)

    Batenburg, R.; Hassel, D. van; Velden, L. van der

    2013-01-01

    Context: It has become a critical challenge in many countries to ensure sufficient capacity of primary care providers, specifically the capacity of General Practitioners (GPs). In a number of countries, health workforce planning is specifically developed for GPs, increasing the need for reliable and

  19. Where on Earth am I? Don't Worry,. GPS Satellites will Guide you ...

    Indian Academy of Sciences (India)

    ordinate frame shown is the reference frame used by GPS, it is called earth .... the satellite clock offsets five monitoring stations are spread over the earth ..... (P 2) GPS receiver for armoured vehicles (on the right is auxiliary display). ( P 3) GPS ...

  20. How do GPs in Switzerland perceive their patients' satisfaction and expectations? An observational study.

    Science.gov (United States)

    Sebo, Paul; Herrmann, François R; Haller, Dagmar M

    2015-06-10

    To assess doctors' perceptions of their patients' satisfaction and expectations in primary care. Cross-sectional study using questionnaires completed by general practitioners (GPs) and their patients. Primary care practices in Geneva, Switzerland. 23 GPs from a random list of 75 GPs practising in the canton of Geneva (participation rate 31%), who each recruited between 50 and 100 consecutive patients coming to the practice for a scheduled medical consultation, leading to a total of 1637 patients (participation rate: 97%, women: 63%, mean age: 54 years). Patient exclusion criteria were: new patients, those consulting in an emergency situation or suffering from disorders affecting their ability to consent, and those who did not speak French. Patients satisfaction with and expectations from the care they received in this practice; GPs perceptions of their patient's satisfaction and expectations. GPs underestimated all patient satisfaction items (p<0.001 for all items) whereas they overestimated their expectations, except for equipment (laboratory and X-ray) and some accessibility items. In a multivariate analysis to assess which GP factors were associated with correct assessment of their patients' views, only GPs' certification status was a significant factor. GPs tend to underestimate patients' satisfaction but overestimate their expectations in primary care. These findings may help GPs to understand patients' views in order to adequately meet their expectations and concerns. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  1. Good end-of-life care according to patients and their GPs.

    NARCIS (Netherlands)

    Borgsteede, S.D.; Graafland-Riedstra, C.; Deliens, L.; Francke, A.L.; Eijk, J.T.M. van; Willems, D.L.

    2006-01-01

    Background: Most patients prefer to die at home, where a GP provides end-of-life care. A few previous studies have been directed at the GPs' values on good end-of-life care, yet no study combined values of patients and their own GP. Aim: To explore the aspects valued by both patients and GPs in

  2. Variation in diagnosis and management of common foot problems by GPs

    NARCIS (Netherlands)

    Gorter, K; de Melker, R; Kuyvenhoven, M; de Poel, S.

    2001-01-01

    Background. There are indications that the diagnosis and management of common foot problems vary widely in general practice. Objectives. Our aim was to explore the variation of GPs' diagnosis and management of common foot problems and the possible correlation between GPs' characteristics and their

  3. GPS-based household interview survey for the Cincinnati, Ohio Region.

    Science.gov (United States)

    2012-02-01

    Methods for Conducting a Large-Scale GPS-Only Survey of Households: Past Household Travel Surveys (HTS) in the United States have only piloted small subsamples of Global Positioning Systems (GPS) completes compared with 1-2 day self-reported travel i...

  4. Latitudinal variation in the occurrence of GPS L-band scintillations ...

    Indian Academy of Sciences (India)

    TEC (ROT) and the rate of change of TEC index. (ROTI) have been studied by several researchers to ... is also of interest to study the spatial and tempo- ral variabilities of the GPS L-band scintillations in ...... tional GPS Service for Geodynamics, Berne, Switzerland,. March 25–26, 351p. Weber E J, Basu S, Bullett T W, ...

  5. Drug reimbursement and GPs' prescribing decisions: a randomized case-vignette study about the pharmacotherapy of obesity associated with type 2 diabetes: how GPs react to drug reimbursement.

    Science.gov (United States)

    Verger, Pierre; Rolland, Sophie; Paraponaris, Alain; Bouvenot, Julien; Ventelou, Bruno

    2010-08-01

    This study sought to identify the effect of drug reimbursability--a decision made in France by the National Authority for Health--on physicians' prescribing practices for a diet drug such as rimonabant, approved for obese or overweight patients with type-2 diabetes. A cross-sectional survey of French general practitioners (GPs) presented a case-vignette about a patient for whom this drug is indicated in two alternative versions, differing only in its reimbursability, to two separate randomized subsamples of GPs in early 2007, before any decision was made about reimbursement. The results indicate that (i) more than 20% of GPs in private practice would be willing to prescribe a non-reimbursed diet drug for patients with obesity complicated by type 2 diabetes; (ii) the number of GPs willing to prescribe it would increase by 47.6% if the drug were reimbursed, and (iii) such a drug would be adopted at a higher rate by GPs who have regular contacts with pharmaceutical sales representatives. In France, unlike most other countries, drug reimbursement status is a signal of quality. However, our results suggest that a significant proportion of GPs would spontaneously adopt anti-obesity drugs even if they were not reimbursed. Decisions about reimbursement of pharmaceutical products should be made taking into account that reimbursement is likely to intensify prescription.

  6. On stochastic modeling of the modernized global positioning system (GPS) L2C signal

    International Nuclear Information System (INIS)

    Elsobeiey, Mohamed; El-Rabbany, Ahmed

    2010-01-01

    In order to take full advantage of the modernized GPS L2C signal, it is essential that its stochastic characteristics and code bias be rigorously determined. In this paper, long sessions of GPS measurements are used to study the stochastic characteristics of the modernized GPS L2C signal. As a byproduct, the stochastic characteristics of the legacy GPS signals, namely C/A and P2 codes, are also determined, which are used to verify the developed stochastic model of the modernized signal. The differential code biases between P2 and C2, DCB P2-C2 , are also estimated using the Bernese GPS software. It is shown that the developed models improved the precise point positioning (PPP) solution and convergence time

  7. Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS)

    Science.gov (United States)

    Truong, S. H.; Hartman, K. R.; Weidow, D. A.; Berry, D. L.; Oza, D. H.; Long, A. C.; Joyce, E.; Steger, W. L.

    1996-01-01

    The Goddard Space Flight Center Flight Dynamics and Mission Operations Divisions have jointly investigated the feasibility of engineering modular Global Positioning SYSTEM (GPS) navigation software to support both real time flight and ground postprocessing configurations. The goals of this effort are to define standard GPS data interfaces and to engineer standard, reusable navigation software components that can be used to build a broad range of GPS navigation support applications. The paper discusses the GPS modular software (GMOD) system and operations concepts, major requirements, candidate software architecture, feasibility assessment and recommended software interface standards. In additon, ongoing efforts to broaden the scope of the initial study and to develop modular software to support autonomous navigation using GPS are addressed,

  8. NONLINEAR FILTER METHOD OF GPS DYNAMIC POSITIONING BASED ON BANCROFT ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    ZHANGQin; TAOBen-zao; ZHAOChao-ying; WANGLi

    2005-01-01

    Because of the ignored items after linearization, the extended Kalman filter (EKF) becomes a form of suboptimal gradient descent algorithm. The emanative tendency exists in GPS solution when the filter equations are ill-posed. The deviation in the estimation cannot be avoided. Furthermore, the true solution may be lost in pseudorange positioning because the linearized pseudorange equations are partial solutions. To solve the above problems in GPS dynamic positioning by using EKF, a closed-form Kalman filter method called the two-stage algorithm is presented for the nonlinear algebraic solution of GPS dynamic positioning based on the global nonlinear least squares closed algorithm--Bancroft numerical algorithm of American. The method separates the spatial parts from temporal parts during processing the GPS filter problems, and solves the nonlinear GPS dynamic positioning, thus getting stable and reliable dynamic positioning solutions.

  9. Spread of ice mass loss into northwest Greenland observed by GRACE and GPS

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Wahr, John; Bevis, Michael

    2010-01-01

    Global Positioning System (GPS) measurements from three long-term sites on bedrock adjacent to the ice sheet. The GRACE results provide a direct measure of mass loss averaged over scales of a few hundred km. The GPS data are used to monitor crustal uplift caused by ice mass loss close to the sites....... The GRACE results can be used to predict crustal uplift, which can be compared with the GPS data. In addition to showing that the northwest ice sheet margin is now losing mass, the uplift results from both the GPS measurements and the GRACE predictions show rapid acceleration in southeast Greenland in late...... 2003, followed by a moderate deceleration in 2006. Because that latter deceleration is weak, southeast Greenland still appears to be losing ice mass at a much higher rate than it was prior to fall 2003. In a more general sense, the analysis described here demonstrates that GPS uplift measurements can...

  10. Lost to the NHS: a mixed methods study of why GPs leave practice early in England.

    Science.gov (United States)

    Doran, Natasha; Fox, Fiona; Rodham, Karen; Taylor, Gordon; Harris, Michael

    2016-02-01

    The loss of GPs in the early stages of their careers is contributing to the GP workforce crisis. Recruitment in the UK remains below the numbers needed to support the demand for GP care. To explore the reasons why GPs leave general practice early. A mixed methods study using online survey data triangulated with qualitative interviews. Participants were GPs aged pressures of increased patient demand and the negative media portrayal left many feeling unsupported and vulnerable to burnout and ill health, and, ultimately, to the decision to leave general practice. To improve retention of young GPs, the pace of administrative change needs to be minimised and the time spent by GPs on work that is not face-to-face patient care reduced. © British Journal of General Practice 2016.

  11. Operational aspects of CASA UNO '88-The first large scale international GPS geodetic network

    Science.gov (United States)

    Neilan, Ruth E.; Dixon, T. H.; Meehan, Thomas K.; Melbourne, William G.; Scheid, John A.; Kellogg, J. N.; Stowell, J. L.

    1989-01-01

    For three weeks, from January 18 to February 5, 1988, scientists and engineers from 13 countries and 30 international agencies and institutions cooperated in the most extensive GPS (Global Positioning System) field campaign, and the largest geodynamics experiment, in the world to date. This collaborative eperiment concentrated GPS receivers in Central and South America. The predicted rates of motions are on the order of 5-10 cm/yr. Global coverage of GPS observations spanned 220 deg of longitude and 125 deg of latitude using a total of 43 GPS receivers. The experiment was the first civilian effort at implementing an extended international GPS satellite tracking network. Covariance analyses incorporating the extended tracking network predicted significant improvement in precise orbit determination, allowing accurate long-baseline geodesy in the science areas.

  12. Radio-tracking large wilderness mammals: integration of GPS and Argos technologies

    Science.gov (United States)

    Schwartz, Charles C.; Arthur, Steve M.

    1999-01-01

    We tested 30 prototype global positioning system (GPS) radiocollars on brown bears (Ursus arctos) over a 3-year period on the Kenai Peninsula, Alaska. Collars were of 2 design types: GPS units with an Argos (Argos Data collection and Location System) satellite uplink (n = 19) and GPS units where the data were stored on board (n = 10) for retrieval at a later date. All units also contained a conventional VHF (very high frequency) transmitter and weighed 1.7 kg. GPS-Argos units obtained 10-82% of expected GPS fixes, and fix rate declined significantly (P bears varied more and were lower than fix rates for stationary collars placed in various vegetation types, suggesting that the bear, terrain, and movement all influence both fix and uplink success rate. Application of this new technology to grizzly and brown bear research and comparisons to studies with moose (Alces alces) are discussed.

  13. On the issues of probability distribution of GPS carrier phase observations

    Science.gov (United States)

    Luo, X.; Mayer, M.; Heck, B.

    2009-04-01

    In common practice the observables related to Global Positioning System (GPS) are assumed to follow a Gauss-Laplace normal distribution. Actually, full knowledge of the observables' distribution is not required for parameter estimation by means of the least-squares algorithm based on the functional relation between observations and unknown parameters as well as the associated variance-covariance matrix. However, the probability distribution of GPS observations plays a key role in procedures for quality control (e.g. outlier and cycle slips detection, ambiguity resolution) and in reliability-related assessments of the estimation results. Under non-ideal observation conditions with respect to the factors impacting GPS data quality, for example multipath effects and atmospheric delays, the validity of the normal distribution postulate of GPS observations is in doubt. This paper presents a detailed analysis of the distribution properties of GPS carrier phase observations using double difference residuals. For this purpose 1-Hz observation data from the permanent SAPOS

  14. FAA aircraft certification human factors and operations checklist for standalone GPS receivers (TSO C129 Class A)

    Science.gov (United States)

    1995-04-01

    This document is a checklist designed to assist Federal Aviation Administration(FAA) certification personnel and global : positioning system (GPS) receiver manufacturers in the evaluation of the pilot-system interface characteristlcs of GPS : recieve...

  15. Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver

    Science.gov (United States)

    Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.

    2012-01-01

    Global Positioning System (GPS)-based navigation has become common for low-Earth orbit spacecraft as the signal environment is similar to that on the Earth s surface. The situation changes abruptly, however, for spacecraft whose orbital altitudes exceed that of the GPS constellation. Visibility is dramatically reduced and signals that are present may be very weak and more susceptible to interference. GPS receivers effective at these altitudes require increased sensitivity, which often requires a high-gain antenna. Pointing such an antenna can pose a challenge. One efficient approach to mitigate these problems is the use of a digitally steered antenna array. Such an antenna can optimally allocate gain toward desired signal sources and away from interferers. This paper presents preliminary results in the development and test of a digitally steered antenna array for the Navigator GPS research program at NASA s Goddard Space Flight Center. In particular, this paper highlights the development of an array and front-end electronics, the development and test of a real-time software GPS receiver, and implementation of three beamforming methods for combining the signals from the array. Additionally, this paper discusses the development of a GPS signal simulator which produces digital samples of the GPS L1C/A signals as they would be received by an arbitrary antenna array configuration. The simulator models transmitter and receiver dynamics, near-far and multipath interference, and has been a critical component in both the development and test of the GPS receiver. The GPS receiver system was tested with real and simulated GPS signals. Preliminary results show that performance improvement was achieved in both the weak signal and interference environments, matching analytical predictions. This paper summarizes our initial findings and discusses the advantages and limitations of the antenna array and the various beamforming methods.

  16. Diagnosing skin disease in primary care: a qualitative study of GPs' approaches.

    Science.gov (United States)

    Rübsam, Marie-Luise; Esch, Maximilian; Baum, Erika; Bösner, Stefan

    2015-10-01

    Skin diseases are a common reason for consulting a GP. This regular occurrence happens despite most GPs' lack of knowledge and training in skin disease. We aimed to explore different diagnostic approaches of GPs in patients presenting with a dermatological problem. In addition, we aimed to identify strategies used by GPs to handle diagnostic uncertainty in these patients. We conducted interviews (20-40 minutes) with 14 GPs using a semi-structured guideline. Recalling encounters with patients with skin disease, GPs described their individual diagnostic strategies. Interviews were taped and transcribed verbatim. Qualitative analysis was conducted by two independent raters using a deductive-inductive approach. We identified several aspects of a complex decision-making process in GPs' diagnostic management of patients with dermatological problems. In the general diagnostic workup, GPs used a broad spectrum of different strategies such as spot diagnosis, stepwise refinement, pattern recognition trigger or test of treatment. GPs reduced diagnostic uncertainty through the identification of red flags, the application of the test of time, therapeutic trials and asking for further advice, including patient referral. GPs encounter a broad range of dermatological problems in their daily work using a variety of strategies in the workup of these patients. However, in a significant number of patients, there remains diagnostic uncertainty that is mainly reduced by specialist referral. Regular training in the diagnosis and treatment of common dermatological diseases should be offered to all GPs. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Seasonal Hydrological Loading in Southern Tibet Detected by Joint Analysis of GPS and GRACE.

    Science.gov (United States)

    Zou, Rong; Wang, Qi; Freymueller, Jeffrey T; Poutanen, Markku; Cao, Xuelian; Zhang, Caihong; Yang, Shaomin; He, Ping

    2015-12-04

    In southern Tibet, ongoing vertical and horizontal motions due to the collision between India and Eurasia are monitored by large numbers of global positioning system (GPS) continuous and campaign sites installed in the past decade. Displacements measured by GPS usually include tectonic deformation as well as non-tectonic, time-dependent signals. To estimate the regional long-term tectonic deformation using GPS more precisely, seasonal elastic deformation signals associated with surface loading must be removed from the observations. In this study, we focus on seasonal variation in vertical and horizontal motions of southern Tibet by performing a joint analysis of GRACE (Gravity Recovery and Climate Experiment) and GPS data, not only using continuous sites but also GPS campaign-mode sites. We found that the GPS-observed and GRACE-modeled seasonal oscillations are in good agreements, and a seasonal displacement model demonstrates that the main reason for seasonal variations in southern Tibet is from the summer monsoon and its precipitation. The biggest loading appears from July to August in the summer season. Vertical deformations observed by GPS and modeled by GRACE are two to three times larger than horizontal oscillations, and the north components demonstrate larger amplitudes than the east components. We corrected the GPS position time series using the GRACE-modeled seasonal variations, which gives significant reductions in the misfit and weighted root-mean-squares (WRMS). Misfit (χ2 divided by degree of freedom) reductions for campaign sites range between 20% and 56% for the vertical component, and are much smaller for the horizontal components. Moreover, time series of continuous GPS (cGPS) sites near the 2015 Nepal earthquakes must be corrected using appropriate models of seasonal loading for analyzing postseismic deformation to avoid biasing estimates of the postseismic relaxation.

  18. GPs' mental wellbeing and psychological resources: a cross-sectional survey.

    Science.gov (United States)

    Murray, Marylou Anna; Cardwell, Chris; Donnelly, Michael

    2017-08-01

    The negative impact of work has been the traditional focus of GP surveys. We know little about GP positive mental health and psychological resources. To profile and contextualise GP positive mental health and personal psychological resources. Cross-sectional survey of GPs working in Northern Ireland (NI). A questionnaire comprising the Warwick Edinburgh Mental Wellbeing Scale (WEMWBS) and measures of resilience, optimism, self-efficacy, and hope, and sociodemographic information was posted to 400 GPs randomly selected from a publicly available GP register. The response rate was 55% (n = 221 out of 400). Mean value for GP wellbeing (WEMWBS) was 50.2 (standard deviation [SD] 8) compared to UK vets 48.8 (SD 9), UK teachers 47.2 (SD 9), and the population of NI 50.8 (SD 9). After adjustment for confounding, mean WEMWBS was 2.4 units (95% CI = 0.02 to 4.7) higher in female GPs than males ( P = 0.05), and 4.0 units (95% CI = 0.8 to 7.3) higher in GPs ≥55 years than GPs ≤44 years ( P = 0.02). Optimism was 1.1 units higher in female GPs than male GPs (95% CI = 0.1 to 2.0), and 1.56 units higher in GPs ≥55 years (95% CI = 0.2 to 2.9) than in those ≤44 years. Hope was 3 units higher in GPs ≥55 years (95% CI = 0.4 to 5.7) than in those aged 45-54 years. Correlation between WEMWBS and psychological resources was highest with hope ( r = 0.65, P mental health that are comparable to the local population and better than other occupational groups, such as vets and teachers. Male and younger GPs may have most to gain from wellbeing interventions. © British Journal of General Practice 2017.

  19. Review of current GPS methodologies for producing accurate time series and their error sources

    Science.gov (United States)

    He, Xiaoxing; Montillet, Jean-Philippe; Fernandes, Rui; Bos, Machiel; Yu, Kegen; Hua, Xianghong; Jiang, Weiping

    2017-05-01

    The Global Positioning System (GPS) is an important tool to observe and model geodynamic processes such as plate tectonics and post-glacial rebound. In the last three decades, GPS has seen tremendous advances in the precision of the measurements, which allow researchers to study geophysical signals through a careful analysis of daily time series of GPS receiver coordinates. However, the GPS observations contain errors and the time series can be described as the sum of a real signal and noise. The signal itself can again be divided into station displacements due to geophysical causes and to disturbing factors. Examples of the latter are errors in the realization and stability of the reference frame and corrections due to ionospheric and tropospheric delays and GPS satellite orbit errors. There is an increasing demand on detecting millimeter to sub-millimeter level ground displacement signals in order to further understand regional scale geodetic phenomena hence requiring further improvements in the sensitivity of the GPS solutions. This paper provides a review spanning over 25 years of advances in processing strategies, error mitigation methods and noise modeling for the processing and analysis of GPS daily position time series. The processing of the observations is described step-by-step and mainly with three different strategies in order to explain the weaknesses and strengths of the existing methodologies. In particular, we focus on the choice of the stochastic model in the GPS time series, which directly affects the estimation of the functional model including, for example, tectonic rates, seasonal signals and co-seismic offsets. Moreover, the geodetic community continues to develop computational methods to fully automatize all phases from analysis of GPS time series. This idea is greatly motivated by the large number of GPS receivers installed around the world for diverse applications ranging from surveying small deformations of civil engineering structures (e

  20. Accuracy of velocities from repeated GPS surveys: relative positioning is concerned

    Science.gov (United States)

    Duman, Huseyin; Ugur Sanli, D.

    2016-04-01

    Over more than a decade, researchers have been interested in studying the accuracy of GPS positioning solutions. Recently, reporting the accuracy of GPS velocities has been added to this. Researchers studying landslide motion, tectonic motion, uplift, sea level rise, and subsidence still report results from GPS experiments in which repeated GPS measurements from short sessions are used. This motivated some other researchers to study the accuracy of GPS deformation rates/velocities from various repeated GPS surveys. In one of the efforts, the velocity accuracy was derived from repeated GPS static surveys using short observation sessions and Precise Point Positioning mode of GPS software. Velocities from short GPS sessions were compared with the velocities from 24 h sessions. The accuracy of velocities was obtained using statistical hypothesis testing and quantifying the accuracy of least squares estimation models. The results reveal that 45-60 % of the horizontal and none of the vertical solutions comply with the results from 24 h solutions. We argue that this case in which the data was evaluated using PPP should also apply to the case in which the data belonging to long GPS base lengths is processed using fundamental relative point positioning. To test this idea we chose the two IGS stations ANKR and NICO and derive their velocities from the reference stations held fixed in the stable EURASIAN plate. The University of Bern's GNSS software BERNESE was used to produce relative positioning solutions, and the results are compared with those of GIPSY/OASIS II PPP results. First impressions indicate that it is worth designing a global experiment and test these ideas in detail.

  1. GPs' views on managing advanced chronic kidney disease in primary care: a qualitative study.

    Science.gov (United States)

    Tonkin-Crine, Sarah; Santer, Miriam; Leydon, Geraldine M; Murtagh, Fliss E M; Farrington, Ken; Caskey, Fergus; Rayner, Hugh; Roderick, Paul

    2015-07-01

    Chronic kidney disease (CKD) has become a significant part of the GP's workload since the introduction of the National Institute for Health and Care Excellence guidelines in 2008. Patients with advanced CKD (stages G4 and G5) often have comorbidities, varied disease progression, and are likely to be older. GPs may experience difficulties with management decisions for patients with advanced CKD, including when to refer to nephrology. To explore GPs' views of managing patients with advanced CKD and referral to secondary care. Qualitative study with GPs in four areas of England: London, Bristol, Birmingham, and Stevenage. Semi-structured interviews with 19 GPs. Transcribed interviews were thematically analysed. GPs had little experience of managing patients with advanced CKD, including those on dialysis or having conservative care (treatment without dialysis or a transplant), and welcomed guidance. Some GPs referred patients based on renal function alone and some used wider criteria including age and multimorbidity. GPs reported a tension between national guidance and local advice, and some had learnt from experience that patients were discharged back to primary care. GPs with more experience of managing CKD referred patients later, or sometimes not at all, if there were no additional problems and if dialysis was seen as not in the patient's interests. GPs want guidance on managing older patients with advanced CKD and comorbidities, which better incorporates agreement between local and national recommendations to clarify referral criteria. GPs are not generally aware of conservative care programmes provided by renal units, however, they appear happy to contribute to such care or alternatively, lead conservative management with input from renal teams. © British Journal of General Practice 2015.

  2. High-precision coseismic displacement estimation with a single-frequency GPS receiver

    Science.gov (United States)

    Guo, Bofeng; Zhang, Xiaohong; Ren, Xiaodong; Li, Xingxing

    2015-07-01

    To improve the performance of Global Positioning System (GPS) in the earthquake/tsunami early warning and rapid response applications, minimizing the blind zone and increasing the stability and accuracy of both the rapid source and rupture inversion, the density of existing GPS networks must be increased in the areas at risk. For economic reasons, low-cost single-frequency receivers would be preferable to make the sparse dual-frequency GPS networks denser. When using single-frequency GPS receivers, the main problem that must be solved is the ionospheric delay, which is a critical factor when determining accurate coseismic displacements. In this study, we introduce a modified Satellite-specific Epoch-differenced Ionospheric Delay (MSEID) model to compensate for the effect of ionospheric error on single-frequency GPS receivers. In the MSEID model, the time-differenced ionospheric delays observed from a regional dual-frequency GPS network to a common satellite are fitted to a plane rather than part of a sphere, and the parameters of this plane are determined by using the coordinates of the stations. When the parameters are known, time-differenced ionospheric delays for a single-frequency GPS receiver could be derived from the observations of those dual-frequency receivers. Using these ionospheric delay corrections, coseismic displacements of a single-frequency GPS receiver can be accurately calculated based on time-differenced carrier-phase measurements in real time. The performance of the proposed approach is validated using 5 Hz GPS data collected during the 2012 Nicoya Peninsula Earthquake (Mw 7.6, 2012 September 5) in Costa Rica. This shows that the proposed approach improves the accuracy of the displacement of a single-frequency GPS station, and coseismic displacements with an accuracy of a few centimetres are achieved over a 10-min interval.

  3. Railway automatic safety protection system based on GPS

    Directory of Open Access Journals (Sweden)

    Fu Hai Juan

    2016-01-01

    Full Text Available The automatic protection system of railway safety is designed for the railway construction workers to protect alarm, and the safety protection device by using GPS satellite positioning system to acquire location information of the operating point, through the CTC/TDCS system and computer monitoring system for the running of the train position and the arithmetic distance. Achieving timely and continuously forecasts about the distance of the train which is apart from the operating point to prompt the voice alarm of the approaching train. Using digital technology to realize the function of the traditional analog interphone, eliminates the quality problems of the call. With the GSM-R, mobile wireless transmission channel and terminal technology, it overcomes the restrictions of the analog interphone which influenced by communication distance and more problems of blind areas. Finally to achieve practical, convenient, applicable and adaptable design goals.

  4. Inkjet printed circularly polarized antennas for GPS applications

    KAUST Repository

    Farooqui, Muhammad Fahad

    2014-07-01

    Two novel, inkjet printed circularly polarized antenna designs are presented for GPS applications. First antenna design comprises a planar monopole which has been made circularly polarized by the introduction of an L-shaped slit. The antenna shows a gain of 0.2 dBi at 1.575 GHz with 3-dB axial ratio bandwidth of 3.8%. The second antenna design comprises a modified monopole in the form of an inverted L and has been termed as circularly polarized inverted L antenna (CILA). The antenna shows a gain of -2 dBi at 1.575 GHz with 3-dB axial ratio bandwidth of 4.1%. Both the antenna designs are attractive for mobile applications.

  5. Thermospheric neutral densities derived from Swarm accelerometer and GPS data

    DEFF Research Database (Denmark)

    Doornbos, Eelco; Encarnacao, Joao; van den IJss, Jose

    Over the past years, a lot of effort has been put into characterising and correcting the various disturbance signals that were found in the accelerometer data provided by the Swarm satellites. This effort was first and foremost aimed at the Swarm C along-track axis data, which seems to be the least...... affected and most promising data for scientific use. The goal to make the Swarm C accelerometer along-track axis data ready for further processing into level 2 thermosphere density data has now been accomplished, with the help of information on the satellite motion from the GPS tracking as well...... approach, affects the possibility of determining densities from the accelerometer measurements of the Swarm A and B satellites. We also investigate the possibility of determining crosswind speeds from Swarm data.In the meantime, we have investigated the possibility of deriving thermosphere neutral density...

  6. GPS/DR Error Estimation for Autonomous Vehicle Localization.

    Science.gov (United States)

    Lee, Byung-Hyun; Song, Jong-Hwa; Im, Jun-Hyuck; Im, Sung-Hyuck; Heo, Moon-Beom; Jee, Gyu-In

    2015-08-21

    Autonomous vehicles require highly reliable navigation capabilities. For example, a lane-following method cannot be applied in an intersection without lanes, and since typical lane detection is performed using a straight-line model, errors can occur when the lateral distance is estimated in curved sections due to a model mismatch. Therefore, this paper proposes a localization method that uses GPS/DR error estimation based on a lane detection method with curved lane models, stop line detection, and curve matching in order to improve the performance during waypoint following procedures. The advantage of using the proposed method is that position information can be provided for autonomous driving through intersections, in sections with sharp curves, and in curved sections following a straight section. The proposed method was applied in autonomous vehicles at an experimental site to evaluate its performance, and the results indicate that the positioning achieved accuracy at the sub-meter level.

  7. Exploring Urban Taxi Drivers’ Activity Distribution Based on GPS Data

    Directory of Open Access Journals (Sweden)

    Xiaowei Hu

    2014-01-01

    Full Text Available With the rapid development of information communication technology and data mining technology, we can obtain taxi vehicle’s real time operation status through the large-scale taxi GPS trajectories data and explore the drivers’ activity distribution characteristics. Based on the 204 continuous hours of 3198 taxi vehicles’ operation data of Shenzhen, China, this paper analyzed the urban taxi driver’s activity distribution characteristics from different temporal and spatial levels. In the time level, we identified the difference with taxi daily operation pattern (weekday versus weekends, continuous time in one day, passengers in vehicle time, and taxi drivers’ operation frequency; in the space level, we explored the taxi driver’s searching pattern, including searching activity space distribution and the relationship between the pick-up locations and the drop-off locations. This research can be helpful for urban taxi drivers’ operation and behavior pattern identification, as well as the contribution to the geographical activity space analysis.

  8. A low-power CMOS frequency synthesizer for GPS receivers

    International Nuclear Information System (INIS)

    Yu Yunfeng; Xiao Shimao; Zhuang Haixiao; Ma Chengyan; Ye Tianchun; Yue Jianlian

    2010-01-01

    A low-power frequency synthesizer for GPS/Galileo L1/E1 band receivers implemented in a 0.18 μm CMOS process is introduced. By adding clock-controlled transistors at latch outputs to reduce the time constant at sensing time, the working frequency of the high-speed source-coupled logic prescaler supplying quadrature local oscillator signals has been increased, compared with traditional prescalers. Measurement results show that this synthesizer achieves an in-band phase noise of -87 dBc/Hz at 15 kHz offset, with spurs less than -65 dBc. The whole synthesizer consumes 6 mA in the case of a 1.8 V supply, and its core area is 0.6 mm 2 . (semiconductor integrated circuits)

  9. Low-cost digital GPS receiver with software carrier detection

    Science.gov (United States)

    Wolf, M. H.

    1988-08-01

    The satellite navigation system global positioning system (GPS) will play a major role in the field of navigation. It will be able to compete with all previously existing radio navigation systems. Low-cost receivers will be built for a number of civilian users, such as general aviation, sea and land navigation. To permit production at low cost for the civil market, a new technique for a C/A (course and acquisition) code receiver has been developed. All the signal detecting and processing is carried out with the digital signal processing software in a Texas Instruments TMS 320C10. The advantage of this method is that complex functions can be effected in a computer program instead of in analog or digital circuits. This reduces the costs of the parts used in the receiver and also avoids calibration. Taken together, these two features greatly reduce the price of a navigation set. This paper discusses the underlying principles leading to this new receiver.

  10. SunDial: embodied informal science education using GPS

    Directory of Open Access Journals (Sweden)

    Megan K. Halpern

    2011-06-01

    Full Text Available Science centers serve a number of goals for visitors, ideally providing experiences that are educational, social, and meaningful. This paper describes SunDial, a handheld application developed for families to use at a science center. Inspired by the idea of geocaching, the high-tech treasure hunting game that utilizes GPS technologies, SunDial asks families to use a single handheld device to locate and participate in a series of learning modules around the museum. Observations of 10 families suggest that it supports rich informal science education experiences, provides insights about families’ interaction patterns around and with single handheld devices, and demonstrates the value of navigation as an educational experience. Further, using recently released guidelines for Informal Science Education (ISE experiences to inform the design process proved valuable, tying features of the technology to educational and social goals, and giving evidence that explicit reference to these guidelines can improve ISE experiences and technologies.

  11. GPS/DR Error Estimation for Autonomous Vehicle Localization

    Directory of Open Access Journals (Sweden)

    Byung-Hyun Lee

    2015-08-01

    Full Text Available Autonomous vehicles require highly reliable navigation capabilities. For example, a lane-following method cannot be applied in an intersection without lanes, and since typical lane detection is performed using a straight-line model, errors can occur when the lateral distance is estimated in curved sections due to a model mismatch. Therefore, this paper proposes a localization method that uses GPS/DR error estimation based on a lane detection method with curved lane models, stop line detection, and curve matching in order to improve the performance during waypoint following procedures. The advantage of using the proposed method is that position information can be provided for autonomous driving through intersections, in sections with sharp curves, and in curved sections following a straight section. The proposed method was applied in autonomous vehicles at an experimental site to evaluate its performance, and the results indicate that the positioning achieved accuracy at the sub-meter level.

  12. Handbook of satellite orbits from Kepler to GPS

    CERN Document Server

    Capderou, Michel

    2014-01-01

    Fifty years after Sputnik, artificial satellites have become indispensable monitors in many areas, such as economics, meteorology, telecommunications, navigation and remote sensing. The specific orbits are important for the proper functioning of the satellites. This book discusses the great variety of satellite orbits, both in shape (circular to highly elliptical) and properties (geostationary, Sun-synchronous, etc.). This volume starts with an introduction into geodesy. This is followed by a presentation of the fundamental equations of mechanics to explain and demonstrate the properties for all types of orbits. Numerous examples are included, obtained through IXION software developed by the author. The book also includes an exposition of the historical background that is necessary to help the reader understand the main stages of scientific thought from Kepler to GPS. This book is intended for researchers, teachers and students working in the field of satellite technology. Engineers, geographers and all those...

  13. Can education of GPs be a waste of time

    DEFF Research Database (Denmark)

    Eliasson, Gösta; Kjær, Niels Kristian

    Background and aim In general practice, care quality and patient security rests to a great extent upon doctor´s knowledge, skills and attitudes. Throughout their career, doctors continuously learn, maintaining and developing their professional ability. Contrary to what many of us believe, the main...... and for professionals to come together in formal small groups. Many countries have elaborated educational programs for GP:s. of which some are optional and some compulsive. In many countries CME credits are used to ascertain relevant competence and hence to allow for further practicing as a specialist. It has been...... argued (Janet Grant and others) that isolated learning activities like sporadic clinical courses are ineffective, unless they are reflected on and coherently managed as a part of a personal learning plan. This workshop will address two questions: 1. What constitutes a national educational policy designed...

  14. Using GPS Data to Study Neighborhood Walkability and Physical Activity.

    Science.gov (United States)

    Rundle, Andrew G; Sheehan, Daniel M; Quinn, James W; Bartley, Katherine; Eisenhower, Donna; Bader, Michael M D; Lovasi, Gina S; Neckerman, Kathryn M

    2016-03-01

    Urban form characteristics intended to support pedestrian activity, collectively referred to as neighborhood walkability, are thought to increase total physical activity. However, little is known about how neighborhood walkability influences utilization of neighborhood space by residents and their overall physical activity. Sociodemographic information and data on mobility and physical activity over 1-week periods measured by GPS loggers and accelerometers were collected from 803 residents of New York City between November 2010 and November 2011. Potentially accessible neighborhood areas were defined as land area within a 1-kilometer distance of the subject's home (radial buffer) and within a 1-kilometer journey on the street network from the home (network buffer). To define actual areas utilized by subjects, a minimum convex polygon was plotted around GPS waypoints falling within 1 kilometer of the home. A neighborhood walkability scale was calculated for each neighborhood area. Data were analyzed in 2014. Total residential neighborhood space utilized by subjects was significantly associated with street intersection density and was significantly negatively associated with residential density and subway stop density within 1 kilometer of the home. Walkability scale scores were significantly higher within utilized as compared with non-utilized neighborhood areas. Neighborhood walkability in the utilized neighborhood area was positively associated with total weekly physical activity (32% [95% CI=17%, 49%] more minutes of moderate-equivalent physical activity across the interquartile range of walkability). Neighborhood walkability is associated with neighborhood spaces utilized by residents and total weekly physical activity. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Simplex GPS and InSAR Inversion Software

    Science.gov (United States)

    Donnellan, Andrea; Parker, Jay W.; Lyzenga, Gregory A.; Pierce, Marlon E.

    2012-01-01

    Changes in the shape of the Earth's surface can be routinely measured with precisions better than centimeters. Processes below the surface often drive these changes and as a result, investigators require models with inversion methods to characterize the sources. Simplex inverts any combination of GPS (global positioning system), UAVSAR (uninhabited aerial vehicle synthetic aperture radar), and InSAR (interferometric synthetic aperture radar) data simultaneously for elastic response from fault and fluid motions. It can be used to solve for multiple faults and parameters, all of which can be specified or allowed to vary. The software can be used to study long-term tectonic motions and the faults responsible for those motions, or can be used to invert for co-seismic slip from earthquakes. Solutions involving estimation of fault motion and changes in fluid reservoirs such as magma or water are possible. Any arbitrary number of faults or parameters can be considered. Simplex specifically solves for any of location, geometry, fault slip, and expansion/contraction of a single or multiple faults. It inverts GPS and InSAR data for elastic dislocations in a half-space. Slip parameters include strike slip, dip slip, and tensile dislocations. It includes a map interface for both setting up the models and viewing the results. Results, including faults, and observed, computed, and residual displacements, are output in text format, a map interface, and can be exported to KML. The software interfaces with the QuakeTables database allowing a user to select existing fault parameters or data. Simplex can be accessed through the QuakeSim portal graphical user interface or run from a UNIX command line.

  16. Why do GPs leave direct patient care and what might help to retain them? A qualitative study of GPs in South West England.

    Science.gov (United States)

    Sansom, Anna; Terry, Rohini; Fletcher, Emily; Salisbury, Chris; Long, Linda; Richards, Suzanne H; Aylward, Alex; Welsman, Jo; Sims, Laura; Campbell, John L; Dean, Sarah G

    2018-01-10

    To identify factors influencing general practitioners' (GPs') decisions about whether or not to remain in direct patient care in general practice and what might help to retain them in that role. Qualitative, in-depth, individual interviews exploring factors related to GPs leaving, remaining in and returning to direct patient care. South West England, UK. 41 GPs: 7 retired; 8 intending to take early retirement; 11 who were on or intending to take a career break; 9 aged under 50 years who had left or were intending to leave direct patient care and 6 who were not intending to leave or to take a career break. Plus 19 stakeholders from a range of primary care-related professional organisations and roles. Reasons for leaving direct patient care were complex and based on a range of job-related and individual factors. Three key themes underpinned the interviewed GPs' thinking and rationale: issues relating to their personal and professional identity and the perceived value of general practice-based care within the healthcare system; concerns regarding fear and risk, for example, in respect of medical litigation and managing administrative challenges within the context of increasingly complex care pathways and environments; and issues around choice and volition in respect of personal social, financial, domestic and professional considerations. These themes provide increased understanding of the lived experiences of working in today's National Health Service for this group of GPs. Future policies and strategies aimed at retaining GPs in direct patient care should clarify the role and expectations of general practice and align with GPs' perception of their own roles and identity; demonstrate to GPs that they are valued and listened to in planning delivery of the UK healthcare; target GPs' concerns regarding fear and risk, seeking to reduce these to manageable levels and give GPs viable options to support them to remain in direct patient care. © Article author(s) (or their

  17. The use of the AOA TTR-4P GPS receiver in operation at the BIPM for real-time restitution of GPS time

    Science.gov (United States)

    Thomas, Claudine

    1994-01-01

    The Global Positioning System is an outstanding tool for the dissemination of time. Using mono-channel C/A-code GPS time receivers, the restitution of GPS time through the satellite constellation presents a peak-to-peak discrepancy of several tens of nanoseconds without SA but may be as high as several hundreds of nanoseconds with SA. As a consequence, civil users are more and more interested in implementing hardware and software methods for efficient restitution of GPS time, especially in the framework of the project of a real-time prediction of UTC (UTCp) which could be available in the form of time differences (UTCp - GPS time). Previous work, for improving the real-time restitution of GPS time with SA, to the level obtained without SA, focused on the implementation of a Kalman filter based on past data and updated at each new observation. An alternative solution relies upon the statistical features of the noise brought about by SA; it has already been shown that the SA noise is efficiently reduced by averaging data from numerous satellites observed simultaneously over a sufficiently long time. This method was successfully applied to data from a GPS time receiver, model AOA TTR-4P, connected to the cesium clock kept at the BIPM. This device, a multi-channel, dual frequency, P-code GPS time receiver, is one of the first TTR-4P units in operation in a civil laboratory. Preliminary comparative studies of this new equipment with conventional GPS time receivers are described in this paper. The results of an experimental restitution of GPS time, obtained in June 1993, are also detailed: 3 to 6 satellites were observed simultaneously with a sample interval of 15 s, an efficient smoothing of SA noise was realized by averaging data on all observed satellites over more than 1 hour. When the GPS system is complete in 1994, 8 satellites will be observable continuously from anywhere in the world and the same level of uncertainty will be obtained using a shorter averaging

  18. A System to Produce Precise Global GPS Network Solutions for all Geodetic GPS Stations in the World

    Science.gov (United States)

    Blewitt, G.; Kreemer, C. W.

    2010-12-01

    We have developed an end-to-end system that automatically seeks and routinely retrieves geodetic GPS data from ~5000 stations (currently) around the globe, reduces the data into unique, daily global network solutions, and produces high precision time series for station coordinates ready for time-series analysis, geophysical modeling and interpretation. Moreover, “carrier range” data are produced for all stations, enabling epoch-by-epoch tracking of individual station motions by precise point positioning for investigation of sub-daily processes, such as post-seismic after-slip and ocean tidal loading. Solutions are computed in a global reference frame aligned to ITRF, and optionally in user-specified continental-scale reference frames that can filter out common-mode signals to enhance regional strain anomalies. We describe the elements of this system, the underlying signal processing theory, the products, operational statistics, and scientific applications of our system. The system is fundamentally based on precise point positioning using JPL's GIPSY OASIS II software, coupled with ambiguity resolution and a global network adjustment of ~300,000 parameters per day using our newly developed Ambizap3 software. The system is designed to easily and efficiently absorb stations that deliver data very late, by recycling prior computations in the network adjustment, such that the resulting network solution is identical to starting from scratch. Thus, it becomes possible to trawl continuously the Internet for late arriving data, or for newly discovered data, and seamlessly update all GPS station time series using the new information content. As new stations are added to the processing archive, automated e-mail requests are made to H.-G. Scherneck's server at Chalmers University to compute ocean loading coefficients used by the station motion model. Rinex file headers are parsed and compared with alias tables in order to infer the correct receiver type and antenna

  19. A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

    Science.gov (United States)

    Seo, Jiwon; Chen, Yu-Hsuan; De Lorenzo, David S.; Lo, Sherman; Enge, Per; Akos, Dennis; Lee, Jiyun

    2011-01-01

    Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities. PMID:22164116

  20. A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

    Directory of Open Access Journals (Sweden)

    Dennis Akos

    2011-09-01

    Full Text Available Due to their weak received signal power, Global Positioning System (GPS signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs. However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU coupled with a new generation Graphics Processing Unit (GPU having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities.