Sample records for eisei gps seimitsu

  1. GPS

    African Journals Online (AJOL)


    ability, a stand-alone handheld GPS receiver (Garmin. II+) was used by LGU to record the position of the nests of as many of the 2001/02 cohort of wandering albatrosses in Albatross Valley as could be visited in the time available. To avoid unnecessary disturbance to the birds, observations were offset by 2 m to the east of.

  2. GPS Separator

    CERN Multimedia


    Footage of the 70 degree ISOLDE GPS separator magnet MAG70 as well as the switchyard for the Central Mass and GLM (GPS Low Mass) and GHM (GPS High Mass) beamlines in the GPS separator zone. In the GPS20 vacuum sector equipment such as the long GPS scanner 482 / 483 unit, faraday cup FC 490, vacuum valves and wiregrid piston WG210 and WG475 and radiation monitors can also be seen. Also the RILIS laser guidance and trajectory can be seen, the GPS main beamgate switch box and the actual GLM, GHM and Central Beamline beamgates in the beamlines as well as the first electrostatic quadrupoles for the GPS lines. Close up of the GHM deflector plates motor and connections and the inspection glass at the GHM side of the switchyard.

  3. Hacking GPS

    CERN Document Server

    Kingsley-Hughes, Kathie


    * 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

  4. GPS Composite Clock Analysis


    Wright, James R.


    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...

  5. GPS & Roadpricing

    DEFF Research Database (Denmark)

    Zabic, Martina


    normalt kun opnås under åben himmel samt hvor ingen eller meget få hindringer forstyrrer positionbestemmelsen. Derfor er GPS modtagelsen speciel følsom i tætte byområder, hvor signalproblemer ofte skyldes høje bygninger, der blokerer for signalerne. Signalproblemerne ses også i skovområder og ved kørsel...

  6. GPS for land surveyors

    CERN Document Server

    Van Sickle, Jan


    The GPS SignalGlobal Positioning System (GPS) Signal StructureTwo ObservablesPseudorangingCarrier Phase RangingBiases and SolutionsThe Error BudgetDifferencingThe FrameworkTechnological ForerunnersVery Long Baseline InterferometryTransitNavstar GPSGPS Segment OrganizationGPS ConstellationThe Control SegmentReceivers and MethodsCommon Features of GPS ReceiversChoosing a GPS ReceiverSome GPS Surveying MethodsCoordinatesA Few Pertinent Ideas About Geodetic Datums for GPSState Plane CoordinatesHeightsGPS Surveying TechniquesStatic GPS SurveyingReal-Time Kinematic (RTK) and Differential GPS (DGPS)T

  7. GPS Satellite Simulation Facility (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...

  8. GPS Separator HD

    CERN Multimedia


    Footage of the 70 degree ISOLDE GPS separator magnet MAG70 as well as the switchyard for the Central Mass and GLM (GPS Low Mass) and GHM (GPS High Mass) beamlines in the GPS separator zone. In the GPS20 vacuum sector equipment such as the long GPS scanner 482 / 483 unit, faraday cup FC 490, vacuum valves and wiregrid piston WG210 and WG475 and radiation monitors can also be seen. Also the RILIS laser guidance and trajectory can be seen, the GPS main beamgate switch box and the actual GLM, GHM and Central Beamline beamgates in the beamlines as well as the first electrostatic quadrupoles for the GPS lines. Close up of the GHM deflector plates motor and connections and the inspection glass at the GHM side of the switchyard.

  9. GPS Test Facility (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...

  10. Progress on GPS standardization (United States)

    Thomas, C.


    It has been clear for some time that a desirable and necessary step for improvement of the accuracy of GPS time comparisons is to establish GPS standards which may be adopted by receiver designers and users. For this reason, a formal body, the CCDS Group on GPS Time Transfer Standards (CGGTTS), was created in 1991. It operates under the auspices of the permanent CCDS Working Group on TAI, with the objective of recommending procedures and models for operational time transfer by the GPS common-view method. It works in close cooperation with the Subcommittee on Time of the Civil GPS Service Interface Committee. The members of the CGGTTS have met in December 1991 and in June 1992. Following these two formal meetings, a number of decisions were taken for unifying the treatment of GPS short-term data and for standardizing the format of GPS data files. A formal CGGTTS Recommendation is now being written concerning these points. This paper relates on the work carried out by the CGGTTS.

  11. GPS Metric Tracking Unit (United States)


    As Global Positioning Satellite (GPS) applications become more prevalent for land- and air-based vehicles, GPS applications for space vehicles will also increase. The Applied Technology Directorate of Kennedy Space Center (KSC) has developed a lightweight, low-cost GPS Metric Tracking Unit (GMTU), the first of two steps in developing a lightweight, low-cost Space-Based Tracking and Command Subsystem (STACS) designed to meet Range Safety's link margin and latency requirements for vehicle command and telemetry data. The goals of STACS are to improve Range Safety operations and expand tracking capabilities for space vehicles. STACS will track the vehicle, receive commands, and send telemetry data through the space-based asset, which will dramatically reduce dependence on ground-based assets. The other step was the Low-Cost Tracking and Data Relay Satellite System (TDRSS) Transceiver (LCT2), developed by the Wallops Flight Facility (WFF), which allows the vehicle to communicate with a geosynchronous relay satellite. Although the GMTU and LCT2 were independently implemented and tested, the design collaboration of KSC and WFF engineers allowed GMTU and LCT2 to be integrated into one enclosure, leading to the final STACS. In operation, GMTU needs only a radio frequency (RF) input from a GPS antenna and outputs position and velocity data to the vehicle through a serial or pulse code modulation (PCM) interface. GMTU includes one commercial GPS receiver board and a custom board, the Command and Telemetry Processor (CTP) developed by KSC. The CTP design is based on a field-programmable gate array (FPGA) with embedded processors to support GPS functions.

  12. GPS, su datum vertical.

    Directory of Open Access Journals (Sweden)

    Esteban Dörries


    Full Text Available La introducción de la metodología GPS en aplicaciones topográficas y geodésicas pone en notoria evidencia la clásica separación de sistemas de referencia en horizontal y vertical. Con GPS el posicionamiento es tridimensional, pero el concepto de altura difiere del clásico. Si se desea utilizar la información altimétrica debe contemplarse la ondulación del geoide.

  13. Bluetooth GPS logger


    Vymětal, Jan


    Tato práce pojednává o návrhu autonomního zařízení s nízkou spotřebou, které provádí záznam dat z externí GPS prostřednictvím integrovaného Bluetooth modulu se sériovým přenosem. This thesis deals with design of autonomous low-consumption device which is logging dates from external GPS throught Bluetooth serial transfering module. D

  14. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry


    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. 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


    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

  16. Update on GPS Modernization Efforts (United States)


    Space and Missile Systems Center Update on GPS Modernization Efforts 11 June 2015 Col Steve Whitney GPS User Equipment Division PUBLICALLY...DATE 11 JUN 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Update on GPS Modernization Efforts 5a...ORGANIZATION NAME(S) AND ADDRESS(ES) Air Force Space Command,Space and Missile Systems Center, GPS User Equipment Division ,Los Angeles AFB, El Segundo,CA

  17. Sensing Human Activity: GPS Tracking. (United States)

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


    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.

  18. Sensing Human Activity: GPS Tracking (United States)

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


    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

  19. A GPS coverage model (United States)

    Skidmore, Trent A.


    The results of several case studies using the Global Positioning System coverage model developed at Ohio University are summarized. Presented are results pertaining to outage area, outage dynamics, and availability. Input parameters to the model include the satellite orbit data, service area of interest, geometry requirements, and horizon and antenna mask angles. It is shown for precision-landing Category 1 requirements that the planned GPS 21 Primary Satellite Constellation produces significant outage area and unavailability. It is also shown that a decrease in the user equivalent range error dramatically decreases outage area and improves the service availability.

  20. Continuous professional development for GPs

    DEFF Research Database (Denmark)

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


    . The main motivation for choice of CPD activities included academic interest, experience of patient-related problems in their own surgeries and medical topics where the GPs felt insufficiently confident. CONCLUSIONS: Danish GPs are frequent users of voluntary accredited CPD. Their CPD choices are motivated...

  1. 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.

  2. GPS Position Time Series @ JPL (United States)

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


    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

  3. De GPS al mapa

    Directory of Open Access Journals (Sweden)

    Esteban Dörries


    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.

  4. The need for GPS standardization (United States)

    Lewandowski, Wlodzimierz W.; Petit, Gerard; Thomas, Claudine


    A desirable and necessary step for improvement of the accuracy of Global Positioning System (GPS) time comparisons is the establishment of common GPS standards. For this reason, the CCDS proposed the creation of a special group of experts with the objective of recommending procedures and models for operational time transfer by GPS common-view method. Since the announcement of the implementation of Selective Availability at the end of last spring, action has become much more urgent and this CCDS Group on GPS Time Transfer Standards has now been set up. It operates under the auspices of the permanent CCDS Working Group on TAI and works in close cooperation with the Sub-Committee on Time of the Civil GPS Service Interface Committee (CGSIC). Taking as an example the implementation of SA during the first week of July 1991, this paper illustrates the need to develop urgently at least two standardized procedures in GPS receiver software: monitoring GPS tracks with a common time scale and retaining broadcast ephemeris parameters throughout the duration of a track. Other matters requiring action are the adoption of common models for atmospheric delay, a common approach to hardware design and agreement about short-term data processing. Several examples of such deficiencies in standardization are presented.

  5. Hastighedskort for Danmark vha. GPS

    DEFF Research Database (Denmark)

    Andersen, Ove; Lahrmann, Harry; Torp, Kristian


    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...

  6. 75 FR 8928 - Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800 Interface Control Working Group (ICWG... (United States)


    ... Department of the Air Force Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800Interface Control Working Group... an Interface Control Working Group (ICWG) teleconference meeting for document/s IS-GPS-200E (NAVSTAR GPS Space Segment/Navigation User Interfaces), IS-GPS-705A (NAVSTAR GPS Space Segment/User Segment L5...

  7. Scintillation-Hardened GPS Receiver (United States)

    Stephens, Donald R.


    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.

  8. LADOTD GPS technology management plan. (United States)


    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....

  9. Evaluating elk habitat interactions with GPS collars (United States)

    Mark A. Rumble; Lakhdar Benkobi; Fredrick Lindzey; R. Scott Gamo


    Global positioning systems (GPS) are likely to revolutionize animal telemetry studies. GPS collars allow biologists to collect systematically scheduled data when VHF telemetry data is difficult or impossible to collect. Past studies have shown that the success of GPS telemetry is greater when animals are standing, or in open habitats. To make effective use of GPS...

  10. GPS/INS Sensor Fusion Using GPS Wind up Model (United States)

    Williamson, Walton R. (Inventor)


    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.

  11. 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

  12. Location - Global Positioning System (GPS) Photos (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...

  13. CLPX-Airborne: Airborne GPS Bistatic Radar (United States)

    National Aeronautics and Space Administration — This data set consists of measurements of GPS signals reflected from the Earth's surface and collected on an airborne platform. A modified GPS Delay Mapping Receiver...

  14. GPS Attitude Determination for Launch Vehicles Project (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...

  15. 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)


    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

  16. 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)


    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.

  17. Diagnosing dementia with confidence by GPs.

    NARCIS (Netherlands)

    Hout, H.P.J. van; Vernooij-Dassen, M.J.F.J.; Stalman, W.A.B.


    BACKGROUND: Earlier reports suggest limited clinical reasoning and substantial uncertainty of GPs in assessing patients suspected of dementia. OBJECTIVE: To explore the predictors of GPs to decide on the presence and absence of dementia as well as the predictors of diagnostic confidence of GPs.

  18. Case: The Global Positioning System (GPS) (United States)


    supporting four dedicated GPS Ground Antennas at Cape Canaveral Air Force Station in Florida, the Kwajalein Atoll, the Ascension Islands , and Diego earthquakes using GPS receivers placed along fault lines; and ... GPS also plays a major role in military combat, guiding missiles and bombs to

  19. The SMS-GPS-Trip-Method

    DEFF Research Database (Denmark)

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


    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...

  20. Integrated navigation of aerial robot for GPS and GPS-denied environment (United States)

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


    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.

  1. GPS in Travel and Activity Surveys

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder


    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...... 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. Software defined radio for GPS


    Solé Gaset, Marc


    Projecte realitzat en col.laboració amb el centre Centre Tecnològic de Telecomunicacions de Catalunya (CTTC) This project describes the implementation of a software defined radio (SDR) Global Navigation Satellite System (GNSS) receiver completely real-time. The receiver is based on Global Positioning System (GPS) L1 C/A receiver. Also, the project describes the implementation and shows the improvement of a Double Delta Correlator (DDDLL) respect a typical Delay Locked Loop (DLL) of a re...

  3. GPS Multipath in Urban Environments (United States)

    Bilich, A.; Sella, G.


    Multipath, where a GNSS signal arrives by more than one path, is considered one of the last unmodeled errors remaining in GNSS. Multipath is of great concern because the additional path length traveled by the incoming signal biases the satellite-receiver range and therefore determination of position. Siting a GNSS station in an urban area, in the immediate vicinity of large reflecting objects such as rooftops, buildings, asphalt and concrete parking lots, grassy fields, and chainlink fences, is both a multipath nightmare and a necessary evil. We note that continuously-operating GNSS stations are becoming increasingly common in urban areas, which makes sense as these stations are often installed in support of civil infrastructure (e.g. departments of transportation, strong motion monitoring of buildings in earthquake-prone areas, surveying networks). Urban stations are well represented in geodetic networks such as the CORS (United States) and GeoNet (Japan) networks, with more stations likely to be installed in the coming years. What sources and types of urban multipath are the most detrimental to geodetic GPS positioning? Which reflecting objects are assumed to be a major source of multipath error, but the GPS data show otherwise? Are certain reflecting environments worse for specific applications, i.e. kinematic vs. static positioning? If forced to install a GNSS station in a highly reflective environment, is it possible to rank objects for their multipath severity? To answer these questions, we provide multipath examples taken from continuously- operating GNSS stations sited in urban environments. We concentrate on some of the most common obstacles and reflecting objects for urban sites - rooftops, parking lots, and fences. We analyze the multipath signature of these objects as manifested in the GPS phase, pseudorange, and signal-to-noise ratio (SNR) observables, and also examine multipath impacts on the precision and accuracy of GPS-derived positions.

  4. GPS-Aided Video Tracking

    Directory of Open Access Journals (Sweden)

    Udo Feuerhake


    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.

  5. Applications of GPS technologies to field sports. (United States)

    Aughey, Robert J


    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.

  6. Testing of GPS devices for mobile mapping (mobile mapping with GPS)


    Blažek, Martin


    The diploma thesis studies accuracy of cheap GPS devices intended for mobile mapping in the landscape. Methodlogy for testing the accuracy of two GPS devices was established on the base of studied literature and apllied to two different GPS devices. The first device is PDA ASUS A639 connected by Bluetooth with external GPS reciever Navilock BT-338 and the second one is PDA ASUS A639 using its inbuilt GPS chipset. The result of testing is firstly comparison of accuracy of these two GPS devices...

  7. A civil complement to GPS and Glonass (United States)

    Rosetti, C.


    The difficulties faced by civilian users of the Navstar GPS and the Glonass military satellite navigation systems are discussed, and the solutions being studied in the ESA Navsat program are described. The problems addressed are the incompatibility of GPS and Glonass signal formats, the intentional degradation of GPS accuracy under the Selective Availability policy, and the lack of notification of satellite malfunction in either system. Navsat goals include quasi-real-time integrity monitoring and warning for GPS and Glonass, a signal bridge between GPS and Glonass, and a low-cost 'core' civil satellite system in GEO, under control of an international organization and capable of expansion to global coverage if needed. The GPS and Glonass signal structures are shown in diagrams and characterized in detail, and a procedure for time transfer between the two is outlined. The components of a lightweight Navsat transponder to be added to future communication satellite payloads are listed in tables.

  8. Miniaturized GPS/MEMS IMU integrated board (United States)

    Lin, Ching-Fang (Inventor)


    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.

  9. GPS/GNSS Antenna Characterization : GPS-ABC Workshop V RTCA Washington, DC October 14, 2016. (United States)


    One component of the Department of Transportations GPS Adjacent Band : Compatibility Study is the characterization of GPS/GNSS receiver antennas : Such characterization is needed to: : Compare radiated and conducted (wired) test result...

  10. Part 4: GPS Telemetry Detection Rates (GPS Test Collar Sites), GCS NAD 83 (2015) (United States)

    U.S. Geological Survey, Department of the Interior — Bias correction in GPS telemetry data-sets requires a strong understanding of the mechanisms that result in missing data. We tested wildlife GPS collars in a variety...

  11. The GPS Laser Retroreflector Array Project (United States)

    Merkowitz, Stephen M.


    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.



    Bokan, Samo


    Namen diplomske naloge je izdelati grafično aplikacijo, ki deluje kot kompas in iz signala GPS določi smer neba (sever). Aplikacija, imenovana GPS Kompas, teče na mobilnem aparatu z operacijskim sistemom android in vgrajenim GPS-sprejemnikom. Določa tudi smer gibanja do položaja, ki ga izbere uporabnik. V nalogi predstavimo operacijski sistem android in orodja, ki smo jih uporabili pri razvoju in testiranju aplikacije. Opišemo strukturo in funkcionalnosti GPS-kompasa ter prikažemo njegovo pr...

  13. 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...

  14. Stigma and GPs' perceptions of dementia

    NARCIS (Netherlands)

    Gove, D.; Downs, M.; Vernooij-Dassen, M.; Small, N.


    OBJECTIVES: General practitioners (GPs) are crucial to improving timely diagnosis, but little is reported about how they perceive dementia, and whether their perceptions display any elements of stigma. The aim of this study was to explore how GPs' perceptions of dementia map onto current

  15. Wave measurements using GPS velocity signals. (United States)

    Doong, Dong-Jiing; Lee, Beng-Chun; Kao, Chia Chuen


    This study presents the idea of using GPS-output velocity signals to obtain wave measurement data. The application of the transformation from a velocity spectrum to a displacement spectrum in conjunction with the directional wave spectral theory are the core concepts in this study. Laboratory experiments were conducted to verify the accuracy of the inversed displacement of the surface of the sea. A GPS device was installed on a moored accelerometer buoy to verify the GPS-derived wave parameters. It was determined that loss or drifting of the GPS signal, as well as energy spikes occurring in the low frequency band led to erroneous measurements. Through the application of moving average skill and a process of frequency cut-off to the GPS output velocity, correlations between GPS-derived, and accelerometer buoy-measured significant wave heights and periods were both improved to 0.95. The GPS-derived one-dimensional and directional wave spectra were in agreement with the measurements. Despite the direction verification showing a 10° bias, this exercise still provided useful information with sufficient accuracy for a number of specific purposes. The results presented in this study indicate that using GPS output velocity is a reasonable alternative for the measurement of ocean waves.

  16. GPS queues with heterogeneous traffic classes

    NARCIS (Netherlands)

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


    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

  17. VLBI Type Experimental Observation of GPS (United States)

    Kwak, Younghee; Tetsuro, Kondo; Jun, Amagai; Tadahiro Gotoh; Tetsuo, Sasao; Cho, Jungho; Kim, Tuhwan


    As a preparatory study for Global Positioning System-Very Long Baseline Interferometry (GPS-VLBI) hybrid system, we examined if VLBI type observation of the GPS signal is realizable through a test experiment. The test experiment was performed between Kashima and Koganei, Japan, with 110 km baseline. The GPS L1 and L2 signals were received by commercial GPS antennas, down-converted to video-band signals by specially developed GPS down converters, and then sampled by VLBI samplers. The sampled GPS data were recorded as ordinary VLBI data by VLBI recorders. The sampling frequency was 64 MHz and the observation time was 1 minute. The recorded data were correlated by a VLBI correlator. From correlation results, we simultaneously obtained correlation fringes from all 8 satellites above a cut-off elevation which was set to 15 degree. 87.5% of L1 fringes and 12.5% of L2 fringes acquired the Signal to Noise Ratios which are sufficient to achieve the group delay precision of 0.1nse! c that is typical in current geodetic VLBI. This result shows that VLBI type observation of GPS satellites will be readily realized in future GPS-VLBI hybrid system.

  18. Application of real-time GPS to earthquake early warning

    National Research Council Canada - National Science Library

    Richard M. Allen; Alon Ziv


      Real-time GPS can provide static-offset observations during an earthquake Real-time GPS provides a robust constrain on magnitude for warnings GPS networks should be used as a companion to seismic...

  19. GPS Precision Timing at CERN

    CERN Document Server

    Beetham, C G


    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).

  20. Briefing highlights space weather risks to GPS (United States)

    Tretkoff, Ernie


    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.

  1. NASA's GPS tracking system for Aristoteles (United States)

    Davis, E. S.; Hajj, G.; Kursinski, E. R.; Kyriacou, C.; Meehan, T. K.; Melbourne, William G.; Neilan, R. E.; Young, L. E.; Yunck, Thomas P.


    NASA 's Global Positioning System (GPS) tracking system for Artistoteles receivers and a GPS flight receiver aboard Aristoteles is described. It will include a global network of GPS ground receivers and a GPS flight receiver aboard Aristoteles. The flight receiver will operate autonomously; it will provide real time navigation solutions for Aristoteles and tracking data needed by ESOC for operational control of the satellite. The GPS flight and ground receivers will currently and continuously track all visible GPS satellites. These observations will yield high accuracy differential positions and velocities of Aristoteles in a terrestrial frame defined by the locations of the globally distributed ground work. The precise orbits and tracking data will be made available to science investigators as part of the geophysical data record. The characteristics of the GPS receivers, both flight and ground based, that NASA will be using to support Aristoteles are described. The operational aspects of the overall tracking system, including the data functions and the resulting data products are summarized. The expected performance of the tracking system is compared to Aristoteles requirements and the need to control key error sources such as multipath is identified.

  2. Space Station GPS Multipath Analysis and Validation (United States)

    Hwu, Shian U.; Loh, Y. C.


    To investigate the multipath effects on the International Space Station (ISS) Global Positioning System (GPS) measurement accuracy, experimental and computational investigations were performed to estimate the carrier phase errors due to multipath. A new modeling approach is used to reduce the required computing time by separating the dynamic structure elements from the static structure elements in the multipath computations. This study confirmed that the multipath is a major error source to the ISS GPS performance and can possibly degrade the attitude determination solution. It is demonstrated that the GPS antenna carrier phase errors due to multipath can be analyzed using the electromagnetic modeling technique such as the Uniform Geometrical Theory of Diffraction (UTD).

  3. Mining significant semantic locations from GPS data

    DEFF Research Database (Denmark)

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


    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...

  4. Using GPS for studying pastoral mobility

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine


    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...... of the practical aspects of using GPS, taking the reader to the heart of some methodological issues that arose in the course of the research. The case sheds light on the particular challenges in using GPS for eliciting information about pastoral mobility. Thinking about such challenges leads to more general...

  5. GPS Radio Occultation as Part of the Global Observing System for Atmosphere (United States)

    Mannucci, Anthony J.; Ao, C. O.; Iijima, B. A.; Wilson, B. D.; Yunck, T. P.; Kursinski, E. R.


    Topics include: The Measurement (Physical retrievals based on time standards), GPS Retrieval Products, Retrievals and Radiances: CLARREO Mission, GPS RO and AIRS, GPS RO and Microwave, GPS RO and Radiosondes, GPS/GNSS Science, and Conclusions.

  6. Global Positioning System (GPS) Energetic Particle Data (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...

  7. LADOTD GPS technology management plan : tech summary. (United States)


    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...

  8. SMEX03 Airborne GPS Bistatic Radar Data (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...

  9. GPS: El sistema de posicionamiento global

    National Research Council Canada - National Science Library

    Juan Gilberto Serpas; Manuel Ramírez N; Franklin de Obaldía


    El Sistema de Posicionamiento Global (GPS, por sus siglas en inglés) se ha convertido, en la actualidad, en una herramienta invaluable para el posicionamiento de puntos sobre la superficie terrestre...

  10. NGA’s Relationship with GPS (United States)


    Infrared Radar Multispectral Hyperspectral Gravity Data Elevation Data Open Source Geology GPS Tracking and Coordinate Systems...Hydrographic Data Boundaries, Transportation and Infrastructure Vegetation Remotely Sensed Data Physical Geography Land Cover and Cultural Data

  11. Global Positioning Systems Directorate: GPS Update (United States)


    Evaluation of the Early CNAV Navigation Message", Pstre igenberger. 0 . Montenbruck, U. Hessels ; Study conducted in Europe. 2015 04 29 _ GPS Update Partnership c ounci12015 v6 UNCLASSIFIED/APPROVED FOR PUBLIC RELEASE 12

  12. GPS Enabled Semi-Autonomous Robot (United States)


    AUTONOMOUS ROBOT by Connor F. Bench September 2017 Thesis Advisor: Xiaoping Yun Second Reader: James Calusdian THIS PAGE INTENTIONALLY...AND SUBTITLE GPS ENABLED SEMI-AUTONOMOUS ROBOT 5. FUNDING NUMBERS 6. AUTHOR(S) Connor F. Bench 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...objective of this research is to integrate GPS and local sensory data to allow a robot to operate semi-autonomously outside of a laboratory environment

  13. En Billig GPS Data Analyse Platform

    DEFF Research Database (Denmark)

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


    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....

  14. Holes: Ionospheric Scintillation, GPS and Imputation (United States)


    by Klobuchar [Parkinson et al., 1996]. 2.3.2 Definition, Characteristics and Models. The situation for scintillation, sadly, is not so simple.Groves...and J. A. Klobuchar (2003), Ionospheric scintillation effects on single and dual frequency gps positioning, in Proceedings of ION GPS/GNSS 2003... Klobuchar (1996), Commercial ionospheric scintillation monitoring receiver development and test results, in Proceedings of the 52nd Annual Meeting of the

  15. GPS: Public Utility or Software Platform (United States)


    Ecosystem Aligning Architecture , Governance, and Strategy (Waltham, MA: Elsevier, 2014), 5. 9 false broadcasts.27 The second factor is how the U.S. has...used to help structure policy analysis on GPS’s vulnerabilities. Each theme assumes GPS serves national goals beyond its primary purpose of...surveying, earthquake monitoring, and other activities requiring extreme precise navigation accuracy.177 Similiarly, the Global Differential GPS system

  16. Global Positioning System III (GPS III) (United States)


    program provides Precise Positioning Service (PPS) to military operations and force enhancement. It also provides increased anti-jam power to the earth...meant to augment GPS services . Once implemented, the common civil signal will be jointly broadcast by up to 60 satellites from both GPS and Galileo ...31 Deliveries and Expenditures 34 Operating and Support Cost 35 Common Acronyms and Abbreviations for MDAP Programs Acq O&M - Acquisition

  17. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao


    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.

  18. Analysis list: GPS2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available GPS2 + hg19 http:...// ...

  19. Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities (United States)

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


    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

  20. Evaluation of solar radio bursts' effect on GPS receiver signal tracking within International GPS Service network (United States)

    Chen, Zhiyu; Gao, Yang; Liu, Zhizhao


    The direct interference from solar radio bursts (SRB) has not usually been considered as a potential threat to global positioning system (GPS) signal tracking, since the flux densities of most bursts are below 40,000 solar flux units (sfu), a threat threshold to GPS L1 frequency proposed by Klobuchar et al. (1999). Recent analysis indicated that a much lower threshold should be adopted for codeless or semicodeless dual-frequency GPS receivers. In this investigation, severe signal corruptions were found at dayside International GPS Service GPS receiver stations during a large solar radio burst that accompanied the super flare of 28 October 2003. Almost no GPS L2 signals were tracked during the solar flux peak time for areas near the subsolar point. Correlation analysis was performed between the rate of loss of lock on GPS L2 frequency and solar radio flux density at different bands, and a correlation index as high as 0.75 is revealed in the 1415 MHz solar radiation band, which is located between the two GPS operating frequencies L2 (1227.60 MHz) and L1 (1575.42 MHz). The correlation analysis indicates that GPS signal losses of lock were primarily caused by microwave in-band interference and that the threat threshold of SRB effects on the GPS system should be re-evaluated, since the flux density of the burst at 1415 MHz was just 4,000-12,000 sfu, which is far below the previously proposed threat threshold. The signal-tracking performance of different types of GPS receivers during such a super flare event is also presented.

  1. ionospheric effects on ionospheric effects on gps signal in low gps

    African Journals Online (AJOL)


    position at all different weather around the world [7]–. [9]. Using the GPS dual frequencies receiver system to eliminate ionospheric delays provides a useful tool for .... forecast for the occurrence of 1 - 2 GHz frequency scintillations in the equatorial and low latitude F region using the GPS TEC data [36, 37]. The ionospheric ...

  2. GPS Space Service Volume: Ensuring Consistent Utility Across GPS Design Builds for Space Users (United States)

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


    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.

  3. Physical applications of GPS geodesy: a review. (United States)

    Bock, Yehuda; Melgar, Diego


    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.

  4. Applying GPS to check horizontal control quality

    Directory of Open Access Journals (Sweden)

    Jakub Vincent


    Full Text Available GPS technologies can also be used for check quality in available horizontal point set with coordinates CJ of the frame S-JTSK. When survey and setting-out tasks should be performed in certain area, one can found in it allways some points of the fundamental and detail state controls. To use these points for some actual aims, it is necessary to investigate their compatibility (among the point mark positions and the point coordinate of control points. This can be done using GPS surveying that may be at the same time employed to determine the new point in the relevant area.Principle of quality investigatingf an existing control is founded on determination of point coordinates CJt from GPS measurements. Then, based on discrepancies among the "official" netpoint coordinates CJ and coordinates CJt "given by GPS", it can be estimated the degree and the real compatibility dislocations in the network structure of the existing points.Realisation procedure for the introduced investigation is demonstrated on GPS checking (by SOKKIA STRATUS receivers horizontal control for reconstruction of a railway bridge on river Bodrog in East Slovakia.It can be shown from the results in Table 3, that points P3 and P7 are useless due to their incompatibility (inconsistency in the inspected point set. For other 7 points (Table 7 the average measure of incompatibility reads 9.8 mm that make possible applying these points for precise setting-out


    Directory of Open Access Journals (Sweden)

    K. N. Tahar


    Full Text Available The establishment of ground control points is a critical issue in mapping field, especially for large scale mapping. The fast and rapid technique for ground control point’s establishment is very important for small budget projects. UAV onboard GPS has the ability to determine the point positioning. The objective of this research is to assess the accuracy of unmanned aerial vehicle onboard global positioning system in positioning determination. Therefore, this research used UAV onboard GPS as an alternative to determine the point positioning at the selected area. UAV is one of the powerful tools for data acquisition and it is used in many applications all over the world. This research concentrates on the error contributed from the UAV onboard GPS during observation. There are several points that have been used to study the pattern of positioning error. All errors were analyzed in world geodetic system 84- coordinate system, which is the basic coordinate system used by the global positioning system. Based on this research, the result of UAV onboard GPS positioning could be used in ground control point establishment with the specific error. In conclusion, accurate GCP establishment could be achieved using UAV onboard GPS by applying a specific correction based on this research.

  6. PBO Facility Construction: GPS Network Completed (United States)

    Feaux, F.; Jackson, M.; Blume, F.; Coyle, B.; Walls, C.; Friesen, B.; Austin, K.; Basset, A.; Williams, T.; Jenkins, F.; Kasmer, D.; Lawrence, S.; Enders, M.


    The Plate Boundary Observatory (PBO), part of the larger NSF-funded EarthScope project, will study the three-dimensional strain field resulting from active plate boundary deformation across the Western United States. The PBO construction phase is now completed, which involved the reconnaissance, permitting, installation, documentation, and maintenance of 891 permanent GPS stations and the upgrade of 209 existing stations in five years. Some of the GPS construction highlights from the project will be presented. These highlights include the San Simeon earthquake response, Mount Saint Helens volcano emergency response, the Magnitude 6.0 Parkfield earthquake emergency response, and GPS and tiltmeter installations on Augustine, Akutan, and Unimak Island in Alaska.

  7. Convective towers detection using GPS radio occultations

    DEFF Research Database (Denmark)

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

    The tropical deep convection affects the radiation balance of the atmosphere changing the water vapour mixing ratio and the temperature of the upper troposphere and lower stratosphere. To gain a better understanding of deep convective processes, the study of tropical cyclones could play...... 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...

  8. Dual RF Astrodynamic GPS Orbital Navigator Satellite (United States)

    Kanipe, David B.; Provence, Robert Steve; Straube, Timothy M.; Reed, Helen; Bishop, Robert; Lightsey, Glenn


    Dual RF Astrodynamic GPS Orbital Navigator Satellite (DRAGONSat) will demonstrate autonomous rendezvous and docking (ARD) in low Earth orbit (LEO) and gather flight data with a global positioning system (GPS) receiver strictly designed for space applications. ARD is the capability of two independent spacecraft to rendezvous in orbit and dock without crew intervention. DRAGONSat consists of two picosatellites (one built by the University of Texas and one built by Texas A and M University) and the Space Shuttle Payload Launcher (SSPL); this project will ultimately demonstrate ARD in LEO.

  9. Development of a GPS navigator with Matlab


    Badia Sole, Oriol


    During the autumn course 2007-2008 I was carring out the enterprise practices and the final project in “Centre Tecnològic per a la industria Aeronàutica i de l’Espai” (CTAE). The opportunity to work on CTAE cames up from the need of find a trainee engineer to develop a post-process GPS navigator using Matlab that may be a prototype of a real-time one implemented within a GPS software receiver. Recently, I just had studied RADARTEL and MATLAB, so I had fresh concepts about...

  10. 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...... 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. The GPS measurements are compared with the Arctic tidal model AOTIM-5, which assimilates tide...

  11. IceBridge L0 Raw Kinematics GPS Time Codes (United States)

    National Aeronautics and Space Administration — The NASA IceBridge L0 Raw Kinematics GPS Time Codes (ITKTC0) data set contains time codes generated during flights over Antarctica using the TrueTime 705-101 GPS...

  12. USGS Earthquake Program GPS Use Case : Earthquake Early Warning (United States)


    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...

  13. IceBridge GPS L0 Raw Satellite Navigation Data (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,...

  14. Is GPS telemetry location error screening beneficial? (United States)

    Ironside, Kirsten E.; Mattson, David J.; Arundel, Terry; Hansen, Jered R.


    The accuracy of global positioning system (GPS) locations obtained from study animals tagged with GPS monitoring devices has been a concern as to the degree it influences assessments of movement patterns, space use, and resource selection estimates. Many methods have been proposed for screening data to retain the most accurate positions for analysis, based on dilution of precision (DOP) measures, and whether the position is a two dimensional or three dimensional fix. Here we further explore the utility of these measures, by testing a Telonics GEN3 GPS collar's positional accuracy across a wide range of environmental conditions. We found the relationship between location error and fix dimension and DOP metrics extremely weak (r2adj ∼ 0.01) in our study area. Environmental factors such as topographic exposure, canopy cover, and vegetation height explained more of the variance (r2adj = 15.08%). Our field testing covered sites where sky-view was so limited it affected GPS performance to the degree fix attempts failed frequently (fix success rates ranged 0.00–100.00% over 67 sites). Screening data using PDOP did not effectively reduce the location error in the remaining dataset. Removing two dimensional fixes reduced the mean location error by 10.95 meters, but also resulted in a 54.50% data reduction. Therefore screening data under the range of conditions sampled here would reduce information on animal movement with minor improvements in accuracy and potentially introduce bias towards more open terrain and vegetation.

  15. GPS LifePlan--Leading Campus Change (United States)

    Litecky, Larry; Bruner, Mike; Hageman, Kristin


    The Goals + Plans = Success (GPS) LifePlan is a new and innovative approach to assist and support students in answering critical questions that give direction to their pursuit of success. The program has brought impressive cultural changes to Century College. It benefited new students by establishing a framework for critical decision making that…

  16. Discovering Hidden Treasures with GPS Technology (United States)

    Nagel, Paul; Palmer, Roger


    "I found it!" Addison proudly proclaimed, as she used an iPhone and Global Positioning System (GPS) software to find the hidden geocache along the riverbank. Others in Lisa Bostick's fourth grade class were jealous, but there would be other geocaches to find. With the excitement of movies like "Pirates of the Caribbean" and…

  17. Exploring female GPs' perceptions about medical leadership. (United States)

    Price, Karen; Clearihan, Lynette


    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.

  18. Integrating GPS with Dead Reckoning Sensors

    DEFF Research Database (Denmark)

    Cederholm, Jens Peter


    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...

  19. Ionospheric irregularities at Antarctic using GPS measurements

    Indian Academy of Sciences (India)

    The purpose of this work is to study the behaviour of the ionospheric scintillation at high latitude during geomagnetically quiet and disturbed conditions which is one of the most relevant themes in the space weather studies. Scintillation is a major problem in navigation application using GPS and in satellite communication at ...

  20. Ionospheric irregularities at Antarctic using GPS measurements

    Indian Academy of Sciences (India)

    The purpose of this work is to study the behaviour of the ionospheric scintillation at high latitude during geomagnetically quiet and disturbed conditions which is one of the most relevant themes in ... Severe amplitude fading and strong scintillation affect the reliability of GPS navigational system and satellite communication.

  1. Fundamentals of GPS Receivers A Hardware Approach

    CERN Document Server

    Doberstein, Dan


    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...

  2. GPS pseudolites: Theory, design, and applications (United States)

    Cobb, H. Stewart

    Pseudolites (ground-based pseudo-satellite transmitters) can initialize carrier-phase differential GPS (CDGPS) navigation systems in seconds to perform real-time dynamic positioning with one-sigma errors as low as 1 cm. Previous CDGPS systems were rarely used due to cumbersome initialization procedures requiring up to 30 minutes; initialization of the carrier-phase integer ambiguities via pseudolite removes these constraints. This work describes pseudolites optimized for this application which cost two orders of magnitude less than previous pseudolites. Synchrolites (synchronized pseudolites) which derive their timing from individual Global Positioning System (GPS) satellites are also described. Synchrolites can replace the CDGPS reference station and datalink, while simultaneously serving to initialize CDGPS navigation. A cluster of well-placed synchrolites could enable CDGPS navigation even if only one GPS satellite signal is available. A prototype CDGPS system initialized by pseudolites and synchrolites was designed and tested. The goal of this system, known as the Integrity Beacon Landing System (IBLS), was to provide navigation accurate and reliable enough to land aircraft in bad weather. Flight test results for prototype pseudolite and synchrolite systems, including results from 110 fully automatic landings of a Boeing 737 airliner controlled by IBLS, are presented. Existing pseudolite applications are described, including simulation of the GPS constellation for indoor navigation experiments. Synchrolite navigation algorithms are developed and analyzed. New applications for pseudolites and synchrolites are proposed. Theoretical and practical work on the near/far problem is presented.

  3. Implementing a GPS Waveform Under the Software Communication Architecture (United States)


    or Modem RF front-end), GPS signal processing/correlation deployed on an FPGA or DSP (CAC), GPS (Receiver and Tracking) and Network- Assistance...processing/correlation in an FPGA or DSP (in the testbed this is the CAC board). GPS Receiver, Tracking and Network-Assistance software...application components are deployed on the Host GPP. The GPS applications running on the host GPP are coupled with the VHDL Modem Components through the CAC

  4. Why GPS makes distances bigger than they are

    NARCIS (Netherlands)

    Ranacher, P.; Brunauer, R.; Trutschnig, W; van der Spek, S.C.; Reich, S


    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

  5. 78 FR 67132 - GPS Satellite Simulator Control Working Group Meeting (United States)


    ... Department of the Air Force GPS Satellite Simulator Control Working Group Meeting AGENCY: Space and Missile Systems Center, Global Positioning Systems (GPS) Directorate, Air Force, DoD. ACTION: Meeting notice..., 2013 Vol. 78 No. 206. This new meeting notice is to inform GPS simulator manufacturers, who supply...

  6. 78 FR 63459 - GPS Satellite Simulator Control Working Group Meeting (United States)


    ... 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 and DoD contractors...

  7. 77 FR 70421 - GPS Satellite Simulator Control Working Group Meeting (United States)


    ... 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 simulator manufacturers, who supply products...

  8. Low-cost implementation of Differential GPS using Arduino


    Svaton, Martin


    The thesis proposes the low-cost solution of Differential GPS using Arduino as a Master Control Unit. The thesis provides the methods of GPS position augmentation, which is available for varied applications such as drones or autonomous lawnmowers operated in a private sector. Used methods of GPS positioning accuracy improvements are based on a Satellite-Based Augmentation System (SBAS) and pseudorange residuals.

  9. How does the workload and work activities of procedural GPs compare to non-procedural GPs? (United States)

    Russell, Deborah J; McGrail, Matthew R


    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.

  10. GPS, GNSS, and Ionospheric Density Gradients (United States)

    Kintner, P. M.; O'Hanlon, B.; Humphreys, T. E.


    Ionospheric density and density gradients affect GNSS signals in two ways. They can introduce ranging errors or irregularities that form on the density gradients producing scintillation. Here we focus on the issue of ranging errors. There are two approaches to mitigating ranging errors produced by ionospheric density gradients which can be 20-30 m during major magnetic storms. The first approach is to use a reference receiver(s) to determine the ionospheric contribution to ranging errors. The ranging error is then transmitted to the user for correction within the mobile receiver. This approach is frequently referred to as differential GPS and, when multiple reference receivers are used, the system is referred to as an augmentation system. This approach is vulnerable to ionospheric gradients depending on the reference receiver spacing(s) and latency in applying the correction within the mobile receiver. The second approach is to transmit navigation signals at two frequencies and then use the relative delay between the two signals to both estimate the ranging error and calculate the correct range. Currently the dual frequency technique is used by US military receivers with an encryption key and some civilian receivers which must be stationary and average over times long compared to those required for navigation. However, the technology of space based radio navigation is changing. GPS will soon be a system with three frequencies and multiple codes. Furthermore Europe, Russia, and China are developing independent systems to complement and compete with GPS while India and Japan are developing local systems to enhance GPS performance in their regions. In this talk we address two questions. How do density gradients affect augmentation systems including the social consequences and will the new GPS/GNSS systems with multiple civilian frequencies be able to remove ionospheric errors. The answers are not at all clear.

  11. Phase Calibration of a 2 by 2 GPS Antenna Array Using Real and Simulated Global Positioning System (GPS) Signals

    National Research Council Canada - National Science Library

    Liou, L


    .... A four-channel digital data collecting system was used in the experiment. For a simulated GPS signal, the experiment was conducted in an anechoic chamber in which a GPS simulation system was facilitated...

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

    DEFF Research Database (Denmark)

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


    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...... patient compliance, and (3) GPs' own risk management. There were substantial differences in the attitudes concerning all three themes. Conclusions. The substantial differences in the GPs' personal and professional risk perceptions may be a key to understanding why GPs do not always follow cardiovascular...

  13. Achievement report for fiscal 1998. Research and development project of regional consortiums (energy field in the regional consortiums / research and development of a precise autonomous operating system for large-scale farm use (the first year)); 1998 nendo chiiki consortium energy bun'ya. Daikibo nogyo muke seimitsu jiritsu soko sagyo shien system no kenkyu kaihatsu (dai 1 nendo)

    Energy Technology Data Exchange (ETDEWEB)



    A precise autonomous operating system is under development to commercialize new agricultural tractors that make possible the stable and safe food supply in Hokkaido in the future as the Japan's food base, and meet the regional needs. This paper describes the development achievements during fiscal 1998. A highly precise and robust automatic driving algorithm was developed by adopting RTK-GPS as a navigation sensor, optical fiber gyroscope and machine vision to have them perform active sensor fusion. Autonomous operation was possible with an error of about 15 cm at a speed as high as 3 m/s. Development and prototype fabrication were carried out on a prototype of the precision fertilizer application machine using GPS precise spatial mapping for farm fields, and a precision weeder. In developing the crawler type autonomous vehicle, the obstacle detecting method, the communication system between the base station and the mobile station, and the specifications of the working machine were established. A yield sensor, soil sensing and pasture sensing were discussed, and a method for collecting information required for precise work was proposed. Market size for agricultural machines in Hokkaido was investigated, and trends in America were analyzed. (NEDO)

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

    DEFF Research Database (Denmark)

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


    During the last decade, GPS tracking has become a key technology for data collection. In this chapter, the authors develop a practice-ready guideline for how to design and conduct GPS tracking investigations. They do so by first developing a V-model for GPS tracking, which describes the different...... 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....... phases of a GPS tracking data collection and the choices that have to be made in each phase. Thereafter, the authors show how this model can be applied in practice in a case study. The V-model is the first model that systematically combines methodological insights from the literature on GPS tracking...

  15. GPS: El sistema de posicionamiento global

    Directory of Open Access Journals (Sweden)

    Juan Gilberto Serpas


    Full Text Available El Sistema de Posicionamiento Global (GPS, por sus siglas en inglés se ha convertido, en la actualidad, en una herramienta invaluable para el posicionamiento de puntos sobre la superficie terrestre. Este artículo pretende dar al lector una descripción del GPS, así como la introducción al cálculo de coordenadas para ser usadas tanto en navegación como en labores de topografía y geodesia. Las características principales del sistema son descritas y se introducen los principios básicos para la determinación de coordenadas tanto en modo absoluto como en modo relativo.

  16. GPs perspectives on prescribing intrauterine contraceptive devices. (United States)

    Lodge, Gabrielle; Sanci, Lena; Temple-Smith, Meredith J


    Globally, 14% of women use intrauterine contraceptive devices (IUCDs) for prevention of unplanned pregnancy. In Australia, the use of IUCDs is negligible at METHODS: GPs participated in qualitative interviews in February-May 2016, exploring their knowledge, attitudes and practice around IUCDs. Data were thematically analysed. Overall, 17 GPs were interviewed. They identified key barriers to prescription of IUCDs as misconceptions brought to the consultation, lack of current GP inserters, and issues in referral of patients for insertion. Barriers to prescribing IUCDs create challenges for women in accessing all available contraceptive options. Potential solutions to increase IUCD uptake might include local directories of GP inserters and targeted promotion of IUCD use. Increased GP training is necessary to expand the number of current GP inserters.

  17. Ionospheric corrections for GPS time transfer (United States)

    Rose, Julian A. R.; Watson, Robert J.; Allain, Damien J.; Mitchell, Cathryn N.


    A real-time ionospheric mapping system is tested to investigate its ability to compensate for the ionospheric delay in single-frequency Global Positioning System (GPS) time transfer over Europe. This technique is compared with two other single-frequency systems: one that does not incorporate any ionospheric correction and one that uses the broadcast Klobuchar model. A dual-frequency technique is also shown as a benchmark. A period in March 2003, during a solar maximum, has been used to display results when the ionospheric delays are large and variable. Data from two European GPS monitoring centers were used to test the time-transfer methods. For averaging times between several minutes and a few hours, the instabilities in the time transfers were dominated by ionospheric effects. The instabilities at longer averaging times were found to be due to clock noise and hardware instabilities. Improvements in time-transfer instabilities are shown by using the ionospheric tomography system.

  18. GPS in Pedestrian and Spatial Behaviour Surveys

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder

    with an electronic questionnaire, for example in the shape of a Personal Digital Assistant (PDA) or cell phone, a whole new array of survey possibilities comes into being. Respondents can be asked to register their activities, evaluate or in other ways describe the attractiveness of places based on their actual....... 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...... position in the urban area. Thus a new form of integration between research into activity patterns and urban places will be possible.    The paper presents the possibilities in spatial behaviour and pedestrian surveys with GPS and electronic questionnaires. Demonstrative mapping of test data from passive...

  19. High dynamic GPS receiver validation demonstration (United States)

    Hurd, W. J.; Statman, J. I.; Vilnrotter, V. A.


    The Validation Demonstration establishes that the high dynamic Global Positioning System (GPS) receiver concept developed at JPL meets the dynamic tracking requirements for range instrumentation of missiles and drones. It was demonstrated that the receiver can track the pseudorange and pseudorange rate of vehicles with acceleration in excess of 100 g and jerk in excess of 100 g/s, dynamics ten times more severe than specified for conventional High Dynamic GPS receivers. These results and analytic extensions to a complete system configuration establish that all range instrumentation requirements can be met. The receiver can be implemented in the 100 cu in volume required by all missiles and drones, and is ideally suited for transdigitizer or translator applications.

  20. Family law matters - a guide for GPs. (United States)

    Minnery, Sarah


    General practitioners are regularly called upon to assist their patients in family law disputes. They are often served with a subpoena to produce their patient's file, or that of their children, and can be called upon to provide short reports regarding various health conditions of their patients. Doctors can also sometimes become witnesses in family law litigation and the time needed to participate is rarely compensated. OBJECTIVE This article aims to provide GPs with key information in relation to responding to a subpoena and the preparation of reports in family law matters. Careful preparation of subpoenas and reports by GPs who find themselves embroiled in the family law disputes of their patients can save significant time and costs to all involved.

  1. Saved by Iridium? An Alternative to GPS (United States)


    It receives its name from the Italian astronomer Galileo Galilei .51 The €20 billion European Union project launched the first two satellites on 21...98Grewal, Weill, and Andrews, Global Positioning System, Inertial Navigation, and Integration, 239. 99Goodreads, “ Galileo Galilei ...completes-high-integrity-gps-program-milestones-.html 39 Goodreads. “ Galileo Galilei quotes.” 14190

  2. Using GPS to Detect Imminent Tsunamis (United States)

    Song, Y. Tony


    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

  3. GPS-State of the Art and Application; GPS: Estado del Arte y Aplicacion

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Ceva, A.


    The Global Positioning System (GPS) is a world-wide satellite navigation system. It is formed by a constellation of satellites, ground stations and receivers. This paper describes: The components and functions of the different segments that constitute the system: space segment, control segment and user segment. The services provided by the GPS: precision and standard positioning. The five-step operation principle: triangulation, ranging, timing, and determination of the position of satellites and receivers. It also includes a description of signals and messages. In addition to the above, the article also: Explains measurements errors and how they are corrected and minimized, justifying the appearance of technologies such as the differential GPS. Evaluated and compares the resolutions that can be obtained with the different technologies. Contains cost estimates. Lists the main locations, navigation, follow-up, mapping and timing applications, with details of the fleet location application. (Author)

  4. Inzet RTK-GPS in de teelt van een gewas : met RTK-GPS schoffelen in cichorei na zaaien met RTK-GPS

    NARCIS (Netherlands)

    Bleeker, P.O.


    In juni 2008 werd op het proefbedrijf van PPO in Lelystad onderzoek gedaan naar de invloed van RTK-GPS stuursystemen op de rechtgeleiding van een werktuig. Met RTK-GPS (RTK staat voor Real Time Kinetic) kan op centimeters nauwkeurig gereden worden. De vraag die beantwoord moest worden was: is de

  5. The performance analysis of a real-time integrated INS/GPS vehicle navigation system with abnormal GPS measurement elimination. (United States)

    Chiang, Kai-Wei; Duong, Thanh Trung; Liao, Jhen-Kai


    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.

  6. MicroGPS for Low-Cost Orbit Determination (United States)

    Wu, S. C.; Bertiger, W. I.; Kuang, D.; Lichten, S. M.; Nandi, S.; Romans, L. J.; Srinivasan, J. M.


    This article presents a new technology for satellite orbit determination using a simple Global Positioning System (GPS) receiver (microGPS) with ultra-low cost, power, and mass. The capability of low-cost orbit determination with microGPS for a low Earth-orbiting satellite, Student Nitric Oxide Explorer (SNOE), is demonstrated using actual GPS data from the GPS/Meteorology (MET) satellite. The measurements acquired by the microGPS receiver will be snapshots of carrier Doppler and ambiguous pseudorange. Among the challenges in orbit determination are the resolution of the pseudorange ambiguity; the estimation of the measurement time tag drift, which effects the in-track orbit position solution; and the convergence of the orbit solution from a cold start with essentially no knowledge of the orbit. The effects of data gaps and Doppler data quality are investigated. An efficient data acquisition scenario for SNOE is derived.

  7. Continuing medical education and burnout among Danish GPs

    DEFF Research Database (Denmark)

    Brøndt, Anders; Sokolowski, Ineta; Olesen, Frede


    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...

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

    Directory of Open Access Journals (Sweden)

    IM. O. Widyantara


    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.

  9. Commissioning and GPs: to commit[tee] or not?


    Drake, Julie E.


    Clinical commissioning groups (CCGs), part of the National Health Service since April 2013, are complex organisations requiring buy-in by GPs for strategic success. CCG budgetary deficits and lack of sustained engagement by GPs have been reported. This article utilises evidence of GP experience in commissioning models to determine the factors that may influence engagement in the governance of CCGs by GPs, which is crucial if clinically led commissioning is to be part of a financially sustaina...

  10. Assessing GPS Constellation Resiliency in an Urban Canyon Environment (United States)


    family, future wife, friends, and dog who stood by me throughout the process. Their advice and continual support was pivotal in my successful completion...Analysis. analytics/resilience.htm. Date accessed: 29 September 2014. 17. Frisco, Eric. Urban Ops Vignette Flow Diagram v3...Executive Commit- tee. 2014. GPS and Galileo...Progress Through Partnership. http://www.gps. gov/policy/cooperation/ europe /2007/gps-galileo-fact-sheet.pdf

  11. Nuclear-Powered GPS Spacecraft Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Bernard


    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.

  12. Study of differential GPS system for UAVs


    Trujillo Martí, Oriol


    Objectius del Treball: Els drons o UAV (Unmanned Aerial Vehicles) tenen cada cop més aplicacions civils. En moltes d'aquestes fa falta una precisió en la posició del vehicle superior a la que pot proporcionar un sistema GPS (Global Positioning System) convencional. Es proposa desenvolupar un sistema de baix cost que permeti corregir la posició del vehicle a posteriori (post-processament) a partir de mesures acurades fetes per una estació base fixa receptora de senyals via satèl·lit. Posterior...

  13. GPS-Based AR Games Development Potential

    Directory of Open Access Journals (Sweden)

    Gregorius Alvin Raditya Santoso


    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



    Ravber, Miha


    Diplomska naloga opisuje razvoj Android aplikacije in strežnika ter vso uporabljeno tehnologijo. Predstavljen je koordiniran prenos GPS (ang. Global Positioning System) podatkov iz mobilne naprave do strežnika. Aplikacija pridobi GPS podatke naprave in jih pošlje strežniku, ki te podatke prejema. Strežnik bo tudi krmilil hitrost pošiljanja GPS podatkov s telefona na strežnik. Implementiran sistem tako omogoča uporabo GPS podatkov v različne namene.

  15. Phase Correction for GPS Antenna with Nonunique Phase Center (United States)

    Fink, Patrick W.; Dobbins, Justin


    A method of determining the position and attitude of a body equipped with a Global Positioning System (GPS) receiver includes an accounting for the location of the nonunique phase center of a distributed or wraparound GPS antenna. The method applies, more specifically, to the case in which (1) the GPS receiver utilizes measurements of the phases of GPS carrier signals in its position and attitude computations and (2) the body is axisymmetric (e.g., spherical or round cylindrical) and wrapped at its equator with a single- or multiple-element antenna, the radiation pattern of which is also axisymmetric with the same axis of symmetry as that of the body.

  16. Researches on Application of GPS to Earthquake Monitoring and Prediction

    Directory of Open Access Journals (Sweden)

    Wanju BO


    Full Text Available The earliest researches on application of GPS to earthquake monitoring and prediction in China began in 1980s, and it was limited to learn some relative technology from other countries and do some test with a few of equipments. As the improvement of software for data processing and the depreciating of hardware, several local GPS network had been gradually set up till the end of 1990s, and then more systematically GPS monitoring, data processing and its application research have been done gradually. In this paper, 3 research examples of the application of GPS to earthquake monitoring and prediction are presented.

  17. GENESIS: GPS Environmental and Earth Science Information System (United States)

    Hajj, George


    This presentation reviews the GPS ENvironmental and Earth Science Information System (GENESIS). The objectives of GENESIS are outlined (1) Data Archiving, searching and distribution for science data products derived from Space borne TurboRogue Space Receivers for GPS science and other ground based GPS receivers, (2) Data browsing using integrated visualization tools, (3) Interactive web/java-based data search and retrieval, (4) Data subscription service, (5) Data migration from existing GPS archived data, (6) On-line help and documentation, and (7) participation in the WP-ESIP federation. The presentation reviews the products and services of Genesis, and the technology behind the system.

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

    Directory of Open Access Journals (Sweden)

    Kenji Oguni


    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.

  19. Time Transfer Through GPS, and the Harmonization of GPS, GLONASS and Galileo for Timing (United States)


    stationary single-frequency receiver with the standard Klobuchar model. The upper plot is the receiver’s solution for time, as realized by its 1-pps... Klobuchar , Ionospheric Time-delay Algorithm for Single Frequency GPS users, IEEE Trans. Aerospace & Electrn. Sys., AES-23 (1987) 325-331. [12] J


    Directory of Open Access Journals (Sweden)

    O. N. Skrypnik


    Full Text Available Based on the application of hardware-software complex NI GPS Simulation Toolkit and aviation receiver CH-4312 proposed a method of constructing the fields of GPS precision according to the RAIM receiver (horizontal and vertical geometrical factor system data. By comparing with experimental data the reliability of the obtained results is assessed and limitations on the conditions of use of the complex for investigation of the characteristics of the GPS were found. Built fields precision GPS for two areas of airspace, located in mid-and high latitudes were constructed.

  1. Estimating waste transfer station delays using GPS. (United States)

    Wilson, Bruce Gordon; Vincent, Julie K


    This paper examines the use of on-board global positioning system (GPS) data recorders as a method to collect field data on the movements of solid waste collection vehicles at transfer stations. The movements of five waste collection vehicles using four different transfer facilities were compared over a period of 1 year. The spatial data were analyzed using geofences to determine the amount of time each truck spent on each of four activities: queuing for access to the weigh scale, sitting on the weigh scale, queuing for access to the tipping floor, and unloading waste. The study found that queuing delays can be identified and measured using GPS data. The average time at a facility for all trucks was 16.4 min per visit, with a standard deviation of 14.3 min. Time at the facility ranged between 2 and 111 min per visit and the distribution of time at the facility was positively skewed. Multi-compartment vehicles (co-collection and recycling trucks) spent significantly more time at unloading facilities. There were also significant differences in the length and the location of the queues at different facilities. At one facility, the longest delays were encountered while waiting for the weigh scale, at two facilities trucks experienced delays in obtaining access to the tipping floor, while at the fourth facility no significant delays developed.


    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  3. GPS and Injury Prevention in Professional Soccer. (United States)

    Ehrmann, Fabian E; Duncan, Craig S; Sindhusake, Doungkamol; Franzsen, William N; Greene, David A


    This study investigated the relationship between GPS variables measured in training and gameplay and injury occurrences in professional soccer. Nineteen professional soccer players competing in the Australian Hyundai A-League were monitored for 1 entire season using 5 Hz Global Positioning System (GPS) units (SPI-Pro GPSports) in training sessions and preseason games. The measurements obtained were total distance, high-intensity running distance, very-high-intensity running distance, new body load, and meters per minute. Noncontact soft tissue injuries were documented throughout the season. Players' seasons were averaged over 1- and 4-week blocks according to when injuries occurred. These blocks were compared with each other and with players' seasonal averages. Players performed significantly higher meters per minute in the weeks preceding an injury compared with their seasonal averages (+9.6 and +7.4% for 1- and 4-week blocks, respectively) (p Football Association regulations, the results of this study isolated 2 variables predicting soft tissue injuries for coaches and sports scientists to consider when planning and monitoring training.

  4. Robust GPS carrier tracking under ionospheric scintillation (United States)

    Susi, M.; Andreotti, M.; Aquino, M. H.; Dodson, A.


    Small scale irregularities present in the ionosphere can induce fast and unpredictable fluctuations of Radio Frequency (RF) signal phase and amplitude. This phenomenon, known as scintillation, can degrade the performance of a GPS receiver leading to cycle slips, increasing the tracking error and also producing a complete loss of lock. In the most severe scenarios, if the tracking of multiple satellites links is prevented, outages in the GPS service can also occur. In order to render a GPS receiver more robust under scintillation, particular attention should be dedicated to the design of the carrier tracking stage, that is the receiver's part most sensitive to these types of phenomenon. This paper exploits the reconfigurability and flexibility of a GPS software receiver to develop a tracking algorithm that is more robust under ionospheric scintillation. For this purpose, first of all, the scintillation level is monitored in real time. Indeed the carrier phase and the post correlation terms obtained by the PLL (Phase Locked Loop) are used to estimate phi60 and S4 [1], the scintillation indices traditionally used to quantify the level of phase and amplitude scintillations, as well as p and T, the spectral parameters of the fluctuations PSD. The effectiveness of the scintillation parameter computation is confirmed by comparing the values obtained by the software receiver and the ones provided by a commercial scintillation monitoring, i.e. the Septentrio PolarxS receiver [2]. Then the above scintillation parameters and the signal carrier to noise density are exploited to tune the carrier tracking algorithm. In case of very weak signals the FLL (Frequency Locked Loop) scheme is selected in order to maintain the signal lock. Otherwise an adaptive bandwidth Phase Locked Loop (PLL) scheme is adopted. The optimum bandwidth for the specific scintillation scenario is evaluated in real time by exploiting the Conker formula [1] for the tracking jitter estimation. The performance

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

    DEFF Research Database (Denmark)

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


    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. ...

  6. PDOP values for simulated GPS/Galileo positioning

    DEFF Research Database (Denmark)

    Cederholm, Jens Peter


    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...

  7. Outcome prediction in gastroschisis - The gastroschisis prognostic score (GPS) revisited. (United States)

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


    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.

  8. Coordinate Time and Proper Time in the GPS (United States)

    Matolcsi, T.; Matolcsi, M.


    The global positioning system (GPS) provides an excellent educational example of how the theory of general relativity is put into practice and becomes part of our everyday life. This paper gives a short and instructive derivation of an important formula used in the GPS, and is aimed at graduate students and general physicists. The authors…

  9. GPS Usage in a Population of Low-Vision Drivers. (United States)

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


    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.

  10. Status update on GPS integrity failure modes and effects analysis (United States)


    GPS integrity anomalies have long been of great concern to the civil and military GPS communities for safety-of- life operations. The FAA, USCG, and their international counterparts have focused on how to accomplish integrity monitoring for safety-of...

  11. Effect of forest canopy on GPS-based movement data (United States)

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


    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 (P<0.001) by effects of forest canopy. Global Positioning System error added an average of 27.5% additional...

  12. Operational real-time GPS-enhanced earthquake early warning

    National Research Council Canada - National Science Library

    R Grapenthin; I A Johanson; R M Allen


    .... Recently, a range of high-rate GPS strategies have been demonstrated on off-line data. Here we present the first operational system for real-time GPS-enhanced earthquake early warning as implemented at the Berkeley Seismological Laboratory (BSL...

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

    Indian Academy of Sciences (India)

    tudes were calculated. Ionospheric Pierce Point (IPP) trajectories of the dlft station (an IGS station located at the longitude of 4 ... mate Experiment (GRACE) is a typical low earth orbit (LEO) satellite system with GPS receiver .... of IPP trajectories for both ground and spaceborne. GPS users. The Klobuchar model for ground ...

  14. Backyard Botany: Using GPS Technology in the Science Classroom (United States)

    March, Kathryn A.


    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…

  15. 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 ...

  16. GPS based TEC measurements for a period August 2008 ...

    Indian Academy of Sciences (India)

    for geodesy (eds) Kleusberg A and Teunissen P (Berlin. Heidelberg New York: Springer), pp. 103–140. Langley R, Fedrizzi M, Paula E, Santos M and Komjathy. A 2002 Mapping the low latitude ionosphere with GPS;. GPS World 13(2) 41–46. Laštovicka J 2006 Forcing of the ionosphere by waves from below; J. Atmos. Sol.

  17. Crustal deformations at permanent GPS sites in Denmark

    DEFF Research Database (Denmark)

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


    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...

  18. 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 ...

  19. Derivation of Orthometric Heights from GPS Measured Heights ...

    African Journals Online (AJOL)

    In this study, geometric technique of deriving orthometric height from GPS survey along a profile and the use of EGM 96 geoid model for deriving orthometric height from GPS data (using GNSS solution software) are discussed. The main focus of the research is to critically examine the potentials of these methods with a view ...

  20. Factors affecting GPs workload in the period 1987-2001.

    NARCIS (Netherlands)

    Kolthof, E.D.; Berg, M.J. van den; Bakker, D.H. de


    Background: Like in other countries, Dutch general practitioners (GPs) perceive an increase in workload. Too much work pressure will affect the quality of care and threats the accessibility of health care provided by GPs. Factors on organisational-level, patient-level as well as on GP-level may

  1. An Interdisciplinary Approach at Studying the Earth-Sun System with GPS/GNSS and GPS-like Signals (United States)

    Zuffada, Cinzia; Hajj, George; Mannucci, Anthony J.; Chao, Yi; Ao, Chi; Zumberge, James


    The value of Global Positioning Satellites (GPS) measurements to atmospheric science, space physics, and ocean science, is now emerging or showing a potential to play a major role in the evolving programs of NASA, NSF and NOAA. The objective of this communication is to identify and articulate the key scientific questions that are optimally, or perhaps uniquely, addressed by GPS or GPS-like observations, and discuss their relevance to existing or planned national Earth-science research programs. The GPS-based ocean reflection experiments performed to date have demonstrated the precision and spatial resolution suitable to altimetric applications that require higher spatial resolution and more frequent repeat than the current radar altimeter satellites. GPS radio occultation is promising as a climate monitoring tool because of its benchmark properties: its raw observable is based on extremely accurate timing measurements. GPS-derived temperature profiles can provide meaningful climate trend information over decadal time scales without the need for overlapping missions or mission-to-mission calibrations. By acquiring data as GPS satellites occult behind the Earth's limb, GPS also provides high vertical resolution information on the vertical structure of electron density with global coverage. New experimental techniques will create more comprehensive TEC maps by using signals reflected from the oceans and received in orbit. This communication will discuss a potential future GNSS Earth Observing System project which would deploy a constellation of satellites using GPS and GPS-like measurements, to obtain a) topography measurements based on GPS reflections with an accuracy and horizontal resolution suitable for eddy monitoring, and h) climate-records quality atmospheric temperature profiles. The constellation would also provide for measurements of ionospheric elec tron density. This is a good example of an interdisciplinary mission concept, with broad science objectives

  2. Quantifying deformation in North Borneo with GPS (United States)

    Mustafar, Mohamad Asrul; Simons, Wim J. F.; Tongkul, Felix; Satirapod, Chalermchon; Omar, Kamaludin Mohd; Visser, Pieter N. A. M.


    The existence of intra-plate deformation of the Sundaland platelet along its eastern edge in North Borneo, South-East Asia, makes it an interesting area that still is relatively understudied. In addition, the motion of the coastal area of North-West Borneo is directed toward a frontal fold-and-thrust belt and has been fueling a long debate on the possible geophysical sources behind it. At present this fold-and-thrust belt is not generating significant seismic activity and may also not be entirely active due to a decreasing shelfal extension from south to north. Two sets of Global Positioning System (GPS) data have been used in this study; the first covering a time period from 1999 until 2004 (ending just before the Giant Sumatra-Andaman earthquake) to determine the continuous Sundaland tectonic plate motion, and the second from 2009 until 2011 to investigate the current deformations of North Borneo. Both absolute and relative positioning methods were carried out to investigate horizontal and vertical displacements. Analysis of the GPS results indicates a clear trend of extension along coastal regions of Sarawak and Brunei in North Borneo. On the contrary strain rate tensors in Sabah reveal that only insignificant and inconsistent extension and compression occurs throughout North-West Borneo. Moreover, station velocities and rotation rate tensors on the northern part of North Borneo suggest a clockwise (micro-block) rotation. The first analysis of vertical displacements recorded by GPS in North-West Borneo points to low subsidence rates along the western coastal regions of Sabah and inconsistent trends between the Crocker and Trusmadi mountain ranges. These results have not been able to either confirm or reject the hypothesis that gravity sliding is the main driving force behind the local motions in North Borneo. The ongoing Sundaland-Philippine Sea plate convergence may also still play an active role in the present-day deformation (crustal shortening) in North

  3. A maritime wireless communication primitive power-supplied by GPS (United States)

    Zhou, Youling; Liu, Angli; Du, Wencai; Zhang, Yonghui


    As global positioning systems (GPS) are becoming ubiquitous, GPS signals are populating the space. While such signals have exclusively been used in localization services in the first place, we take the first step in turning them to energy sources for maritime communication. Specifically, we leverage antennas deployed on ships to harvest energy from such ambient GPS signals, which are also fed into encoders to carry information bits. This way, maritime communication can be built completely battery-free all day long. Also, it it because the communication takes place on the ocean, where no interference is introduced, except for the original GPS signals to the backscattered GPS signals, the design of the transceiver under certain energy budget is simplified. In this paper, we show the theoretical promise that the system would work using electromagnetic theories, and introduce our prototype which proves the concept in real world settings.

  4. Estimering af brændstofforbrug vha. GPS Data

    DEFF Research Database (Denmark)

    Andersen, Ove; Lahrmann, Harry; Torp, Kristian


    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...

  5. How and Why to Do VLBI on GPS (United States)

    Dickey, J. M.


    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.

  6. Autonomous Spacecraft Navigation Using Above-the-Constellation GPS Signals (United States)

    Winternitz, Luke


    GPS-based spacecraft navigation offers many performance and cost benefits, and GPS receivers are now standard GNC components for LEO missions. Recently, more and more high-altitude missions are taking advantage of the benefits of GPS navigation as well. High-altitude applications pose challenges, however, because receivers operating above the GPS constellations are subject to reduced signal strength and availability, and uncertain signal quality. This presentation will present the history and state-of-the-art in high-altitude GPS spacecraft navigation, including early experiments, current missions and receivers, and efforts to characterize and protect signals available to high-altitude users. Recent results from the very-high altitude MMS mission are also provided.

  7. Energy efficient LoRa GPS tracker for dementia patients. (United States)

    Hadwen, Tim; Smallbon, Vanessa; Qing Zhang; D'Souza, Matthew


    Continuous GPS tracking devices always suffer short battery life when used by caregivers to reduce the risk of wandering to dangerous areas by dementia patients. Currently the best existing tracker for dementia patients on the market only supports less than 10 hours battery life with a gigantic battery. It not only requires daily battery charging from patients/caregivers, but also becomes a very restrictive device. In this paper we inspected individual energy consumption of the components in a GPS tracker and proposed a novel energy efficient, small wristband by integrating the latest LoRa communication and GPS duty cycling technologies. We verify our prototype's communication distance and energy efficiency through extensive experiments in the real world. Our model and data show the GPS wristband is able to support up to 40 hours continuous GPS tracking with a frequent 60 seconds location update rate. Its range also spans 3km, effectively monitoring patient locations.

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

    DEFF Research Database (Denmark)

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


    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...... signal statistics. To help both users as well as application systems in understanding and mitigating body and environment-induced effects, we propose a method for sensing the current sources of GPS reception impairment in terms of body, urban and indoor conditions. We present results that show...... degradation on modern smart phones for different hand grip styles and body placements can cause signal strength drops as high as 10-16 dB and double the positioning error. Furthermore, existing phone applications designed to help users identify sources of GPS performance impairment are restricted to show raw...

  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)


    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. Ulipristal acetate: An update for Australian GPs. (United States)

    Mazza, Danielle


    In Australia, use and understanding of emergency contraception among women remains relatively low. This is despite the introduction of levonorgestrel emergency contraceptive pills (ECPs) more than a decade ago. In April 2016, a new ECP with the active ingredient ulipristal acetate became available in Australia. The aims of this article are to increase understanding of the recently introduced ulipristal acetate ECP, including its safety profile, effi-cacy and special considerations; dispel common myths and misconceptions about emergency contraception; and to provide guidance on emergency contraceptive management in general practice, considering the recent advances. Women are more receptive to information about emergency contraception that has been provided by a general practitioner (GP). As such, the availability of the ulipristal acetate ECP in Australia provides an important opportunity for GPs to help women prevent unplanned pregnancies.

  11. GPS Software Packages Deliver Positioning Solutions (United States)


    "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. True or false GPS-derived deformations?

    Directory of Open Access Journals (Sweden)

    M. Anzidei


    Full Text Available In this paper we focus on the question whether GPS networks born with cartographic aims can be safely used in crustal deformation control. We carried out a test on a network of five vertices located in the Rome district, comparing two data sets, the first coming from the adjustment of the survey carried out in 1994 in the frame of the IGM95 project, the second coming from the surveys carried out in 1996 and 1999 by the DITS of the "La Sapienza" University of Rome. Our analysis shows how the detection of crustal deformation becomes extremely critical in absence of significant seismicity or when deformation events are limited. In other words, it is possible to find false deformations due to residual systematic effects affecting the coordinate estimates

  13. CASA Uno GPS orbit and baseline experiments (United States)

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


    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.

  14. Navigating the human hippocampus without a GPS. (United States)

    Zucker, Halle R; Ranganath, Charan


    The award of the Nobel Prize to Professors John O'Keefe, May-Britt Moser, and Edvard Moser brings global recognition to one of the most significant success stories in modern neuroscience. Here, we consider how their findings, along with related studies of spatial cognition in rodents, have informed our understanding of the human hippocampus. Rather than identifying a "GPS" in the brain, we emphasize that these researchers helped to establish a fundamental role for cortico-hippocampal networks in the guidance of behavior based on a representation of the current place, time, and situation. We conclude by highlighting the major questions that remain to be addressed in future research. © 2015 Wiley Periodicals, Inc.

  15. High dynamic, low volume GPS receiver (United States)

    Hurd, W. J.


    A new GPS receiver concept and design are presented to meet the high dynamic and low volume requirements for range applications in missiles and drones. The receiver has the potential to satisfy all range requirements with one basic receiver, which has significant potential economic benefit over the alternate approach of using a family of receivers, each tailored for specific applications. The main new concept is to use approximate maximum likelihood estimates of pseudo range and range-rate, rather than tracking with carrier phase locked loops and code delay locked loops. Preliminary analysis indicates that receivers accelerating at 50 g or more can track with position errors due to acceleration of approximately 0.2 m/g, or 10 m at 50 g. Implementation is almost entirely digital to meet the low volume requirements.

  16. GPS-ABC radiated chamber testing overview and results : GPS-ABC Workshop VI : RTCA Washington, DC, March 30, 2017. (United States)


    This presentation, which was given during the GPS-ABC Workshop VI in Washington, DC on March 30, 2017 details the authors' radiated testing protocols and results. GPS receiver testing was carried out April 25-29, 2016 at the Army : Research Laborator...

  17. GPS Imaging of Sierra Nevada Uplift (United States)

    Hammond, W. C.; Blewitt, G.; Kreemer, C.


    Recent improvements in the scope and precision of GPS networks across California and Nevada have allowed for uplift of the Sierra Nevada to be observed directly. Much of the signal, in the range of 1 to 2 mm/yr, has been attributed to lithospheric scale rebound following massive groundwater withdrawal in the San Joaquin Valley in southern California, exacerbated by drought since 2011. However, natural tectonic deformation associated with long term uplift of the range may also contribute to the observed signal. We have developed new algorithms that enhance the signal of Sierra Nevada uplift and improve our ability to interpret and separate natural tectonic signals from anthropogenic contributions. We apply our new Median Interannual Difference Adjusted for Skewness (MIDAS) algorithm to the vertical times series and a inverse distance-weighted median spatial filtering and Delaunay-based interpolation to despeckle the rate map. The resulting spatially continuous vertical rate field is insensitive to outliers and steps in the GPS time series, and omits isolated features attributable to unstable stations or unrepresentative rates. The resulting vertical rate field for California and Nevada exhibits regionally coherent signals from the earthquake cycle including interseismic strain accumulation in Cascadia, postseismic relaxation of the mantle from recent large earthquakes in central Nevada and southern California, groundwater loading changes, and tectonic uplift of the Sierra Nevada and Coast Ranges. Uplift of the Sierra Nevada extends from the Garlock Fault in the south to an indefinite boundary in the north near the latitude of Mt. Lassen to the eastern Sierra Nevada range front in Owen's Valley. The rates transition to near zero in the southern Walker Lane. The eastern boundary of uplift coincides with the highest strain rates in the western Great Basin, suggesting higher normal fault slip rates and a component of tectonic uplift of the Sierra Nevada.

  18. Termination of pregnancy: attitudes and clinical experiences of Irish GPs and GPs-in-training. (United States)

    Murphy, Mark; Vellinga, Akke; Walkin, Scott; MacDermott, Maeve


    Termination of pregnancy (ToP) is currently illegal in Ireland. In 2010, more than 4000 women travelled from Ireland to the UK for a ToP. The aims of this study were to assess the attitudes and clinical experiences of Irish General Practitioners (GPs) and GPs-in-training (GPRs) towards ToP. A postal survey was sent to 500 GPs in Ireland. An internet-based survey was sent to 244 GPRs. Quantitative and qualitative analysis was performed. Overall response was 44%. Four groups of doctor's opinions could be identified: (A) abortion can never be allowed (10%); (B) abortion can be allowed in limited circumstances (25%); (C) abortion should be available to all women (51%); and (D) no definite opinion (14%). Doctors in groups (A) and (B) were older and more often Catholic. Of doctors in group (C), 66% indicated an upper gestational limit of maximum 16 weeks. More than 40% of all respondents had at least one consultation specifically dealing with ToP within the past six months and 43% agreed with the statement that women's health suffers due to the travel related to ToP. Most responding GPs and GPRs (75%) support the provision of ToP in Ireland in certain circumstances. The qualitative analysis of this survey showed that the terms pro-life and pro-choice inappropriately describe the spectrum of opinions. This study highlights clinical situations in which women's health may be adversely affected due to the requirement to travel for ToP.

  19. A Matlab Implementation of Differential GPS for Low-cost GPS Receivers

    Directory of Open Access Journals (Sweden)

    Qasim Ali


    Full Text Available A number of public codes exist for GPS positioning and baseline determination in off-line mode. However, no software code exists for DGPS exploiting correction factors at base stations, without relying on double difference information. In order to accomplish it, a methodology is introduced in MATLAB environment for DGPS using C/A pseudoranges on single frequency L1 only to make it feasible for low-cost GPS receivers. Our base station is at accurately surveyed reference point. Pseudoranges and geometric ranges are compared at base station to compute the correction factors. These correction factors are then handed over to rover for all valid satellites observed during an epoch. The rover takes it into account for its own true position determination for corresponding epoch. In order to validate the proposed algorithm, our rover is also placed at a pre-determined location. The proposed code is an appropriate and simple to use tool for post-processing of GPS raw data for accurate position determination of a rover e.g. Unmanned Aerial Vehicle during post-mission analysis.

  20. 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


    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.

  1. Integrating GPS with GLONASS for high-rate seismogeodesy (United States)

    Geng, Jianghui; Jiang, Peng; Liu, Jingnan


    High-rate GPS is a precious seismogeodetic tool to capture coseismic displacements unambiguously and usually improved by sidereal filtering to mitigate multipath effects dominating the periods of tens of seconds to minutes. We further introduced GLONASS (Globalnaya navigatsionnaya sputnikovaya sistema) data into high-rate GPS to deliver over 2000 24 h displacements at 99 stations in Europe. We find that the major displacement errors induced by orbits and atmosphere on the low-frequency band that are not characterized by sidereal repeatabilities can be amplified markedly by up to 40% after GPS sidereal filtering. In contrast, integration with GLONASS can reduce the noise of high-rate GPS significantly and near uniformly over the entire frequency band, especially for the north components by up to 40%, suggesting that this integration is able to mitigate more errors than only multipath within high-rate GPS. Integrating GPS with GLONASS outperforms GPS sidereal filtering substantially in ameliorating displacement noise by up to 60% over a wide frequency band (e.g., 2 s-0.5 days) except a minor portion between 100 and 1000 s. High-rate multi-GNSS (Global Navigation Satellite System) can be enhanced further by sidereal filtering, which should however be carefully implemented to avoid adverse complications of the noise spectrum of displacements.

  2. Accuracy of High-Rate GPS for Seismology (United States)

    Elosegui, P.; Davis, J. L.; Oberlander, D.; Baena, R.; Ekstrom, G.


    We built a device for translating a GPS antenna on a positioning table to simulate the ground motions caused by an earthquake. The earthquake simulator is accurate to better than 0.1 mm in position, and provides the "ground truth" displacements for assessing the technique of high-rate GPS. We found that the root-mean-square error of the 1-Hz GPS position estimates over the 15-min duration of the simulated seismic event was 2.5 mm, with approximately 96% of the observations in error by less than 5 mm, and is independent of GPS antenna motion. The error spectrum of the GPS estimates is approximately flicker noise, with a 50% decorrelation time for the position error of approx.1.6 s. We that, for the particular event simulated, the spectrum of dependent error in the GPS measurements. surface deformations exceeds the GPS error spectrum within a finite band. More studies are required to determine whether a generally optimal bandwidth exists for a target group of seismic events.

  3. Geomagnetic Storm Impact On GPS Code Positioning (United States)

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


    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

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

    National Research Council Canada - National Science Library

    Leejoice, Robert


    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...

  5. Pilot GPS/LORAN Receiver Programming Performance: A Laboratory Evaluation (United States)


    surrounding each error indicated that specific display design and system logic attributes contributed to the errors. In addition, examination of...Global positioning system (GPS), Long range navigation (LORAN), Error recognition, Error recovery, Menu structure, Display design , Human factors.

  6. DOTD standards for GPS data collection accuracy : research project capsule. (United States)


    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...

  7. PODAAC-J2ODR-GPS00 (United States)

    National Aeronautics and Space Administration — Similar to the OSTM/Jason-2 OGDR, but also includes a GPS based orbit and SSHA calculated from that orbit, as supposed to the DORIS based orbit that is already...

  8. OSTM_L2_OST_OGDR_GPS:1 (United States)

    National Aeronautics and Space Administration — Similar to the OSTM/Jason-2 OGDR, but also includes a GPS based orbit and SSHA calculated from that orbit, as supposed to the DORIS based orbit that is already...

  9. GPS source solution of the 2004 Parkfield earthquake

    CERN Document Server

    Houlie, N; Kim, A


    We compute a series of finite-source parameter inversions of the fault rupture of the 2004 Parkfield earthquake based on 1 Hz GPS records only. We confirm that some of the co-seismic slip at shallow depth (<5 km) constrained by InSAR data processing results from early post-seismic deformation. We also show 1) that if located very close to the rupture, a GPS receiver can saturate while it remains possible to estimate the ground velocity (~1.2 m/s) near the fault, 2) that GPS waveforms inversions constrain that the slip distribution at depth even when GPS monuments are not located directly above the ruptured areas and 3) the slip distribution at depth from our best models agree with that recovered from strong motion data. The 95th percentile of the slip amplitudes for rupture velocities ranging from 2 to 5 km/s is, 55 +/- 6 cm.

  10. GPS source solution of the 2004 Parkfield earthquake. (United States)

    Houlié, N; Dreger, D; Kim, A


    We compute a series of finite-source parameter inversions of the fault rupture of the 2004 Parkfield earthquake based on 1 Hz GPS records only. We confirm that some of the co-seismic slip at shallow depth (GPS receiver can saturate while it remains possible to estimate the ground velocity (~1.2 m/s) near the fault, 2) that GPS waveforms inversions constrain that the slip distribution at depth even when GPS monuments are not located directly above the ruptured areas and 3) the slip distribution at depth from our best models agree with that recovered from strong motion data. The 95(th) percentile of the slip amplitudes for rupture velocities ranging from 2 to 5 km/s is ~55 ± 6 cm.

  11. Cooperative Localization in GPS-Limited Urban Environments (United States)

    Hemmes, Jeffrey; Thain, Douglas; Poellabauer, Christian

    Existing localization techniques such as GPS have fundamental limitations which preclude deployment in urban canyons or areas with inconsistent network availability. Augmenting GPS requires specialized infrastructure or tedious calibration tasks which limit general purpose applications. In this paper, we examine the utility of cooperatively sharing location data among connected nodes in order to correct positions with high measurement error in GPS-limited environments. Using simple data sharing and filtering techniques, collaborating users can substantially reduce overall localization error in dead reckoning systems where nodes may have a broad spectrum of location quality. We examine system parameters necessary to fully exploit cooperative localization based on empirical error models and show that mean position error can be reduced by up to 50 percent for given application scenarios. If distance measurement is available, filtering location information based on estimated error and confidence can improve accuracy of pedestrian dead reckoning techniques to approximately that of GPS using trilateration.

  12. A New Indoor Positioning System Architecture Using GPS Signals. (United States)

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


    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.

  13. Evaluation of GPS/BDS indoor positioning performance and enhancement

    DEFF Research Database (Denmark)

    He, Zhe; Petovello, Mark; Pei, Ling


    This paper assesses the potential of using BDS and GPS signals to position in challenged environments such as indoors. Traditional assisted GNSS approaches that use code phase as measurements (i.e., coarse-time solutions) are shown to be prone to multipath and noise. An enhanced approach that has...... superior sensitivity and positioning performance—the so-called direct positioning receiver architecture—has been implemented and evaluated using live indoor BDS and/or GPS signals. Real indoor experiments have been conducted in Shanghai and significant improvement has been observed with enhanced approaches......: results with BDS constellation show better horizontal positioning performance (biases are less than 10m) than using GPS alone, but are slightly worse in the vertical axis; when using the enhanced approach with BDS and GPS, both horizontal and vertical axes show promising results for the environments...

  14. Evaluation of GPS/BDS indoor positioning performance and enhancement (United States)

    He, Zhe; Petovello, Mark; Pei, Ling; Olesen, Daniel M.


    This paper assesses the potential of using BDS and GPS signals to position in challenged environments such as indoors. Traditional assisted GNSS approaches that use code phase as measurements (i.e., coarse-time solutions) are shown to be prone to multipath and noise. An enhanced approach that has superior sensitivity and positioning performance-the so-called direct positioning receiver architecture-has been implemented and evaluated using live indoor BDS and/or GPS signals. Real indoor experiments have been conducted in Shanghai and significant improvement has been observed with enhanced approaches: results with BDS constellation show better horizontal positioning performance (biases are less than 10 m) than using GPS alone, but are slightly worse in the vertical axis; when using the enhanced approach with BDS and GPS, both horizontal and vertical axes show promising results for the environments considered herein; the coarse-time state converges faster and is more reliable compared to other solutions.

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

    CERN Document Server

    Hofmann-Wellenhof, Bernhard; Wasle, Elmar


    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.

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

    National Research Council Canada - National Science Library

    Joseph, Kurt


    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...

  17. ISOLDE target zone GPS robot Camera B Part1

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements mainly in close up moving a target along the corridor and onto a shelf position and vice versa. Close up GPS robot handling at exchange point. Movement GPS robot with target through the corridor. Close up robot cable guidance system. Close up posing target on the shelf position. Close up picking up a target from the shelf position and passing through corridor. Picking up a target from a shelf position seen from the target front end towards the zone entrance and taking it to the exchange point and vice versa. Checking activation: GPS robot picking up a target from the shelf and moving it in front of the radiation monitor and close up.

  18. ISOLDE target zone GPS robot, Camera B Part2

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements mainly in close up moving a target along the corridor and onto a shelf position and vice versa. Close up GPS robot handling at exchange point. Movement GPS robot with target through the corridor. Close up robot cable guidance system. Close up posing target on the shelf position. Close up picking up a target from the shelf position and passing through corridor. Picking up a target from a shelf position seen from the target front end towards the zone entrance and taking it to the exchange point and vice versa. Checking activation: GPS robot picking up a target from the shelf and moving it in front of the radiation monitor and close up.

  19. ISOLDE target zone GPS robot, Camera B Part2 HD

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements mainly in close up moving a target along the corridor and onto a shelf position and vice versa. Close up GPS robot handling at exchange point. Movement GPS robot with target through the corridor. Close up robot cable guidance system. Close up posing target on the shelf position. Close up picking up a target from the shelf position and passing through corridor. Picking up a target from a shelf position seen from the target front end towards the zone entrance and taking it to the exchange point and vice versa. Checking activation: GPS robot picking up a target from the shelf and moving it in front of the radiation monitor and close up.

  20. ISOLDE target zone GPS robot Camera B Part1 HD

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements mainly in close up moving a target along the corridor and onto a shelf position and vice versa. Close up GPS robot handling at exchange point. Movement GPS robot with target through the corridor. Close up robot cable guidance system. Close up posing target on the shelf position. Close up picking up a target from the shelf position and passing through corridor. Picking up a target from a shelf position seen from the target front end towards the zone entrance and taking it to the exchange point and vice versa. Checking activation: GPS robot picking up a target from the shelf and moving it in front of the radiation monitor and close up.

  1. SMEX02 Airborne GPS Bistatic Radar Data, Iowa (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...

  2. GPS Ice Flow Measurements, Allan Hills, Antarctica, Version 1 (United States)

    National Aeronautics and Space Administration — This data set includes includes high-precision GPS measurements of steel poles within the Allan Hills Main Ice Field, Near Western Ice Field, and extending to the...

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

    Directory of Open Access Journals (Sweden)

    E. Zuccheretti


    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.

  4. 77 FR 23668 - GPS Satellite Simulator Working Group Notice of Meeting (United States)


    ... Department of the Air Force GPS Satellite Simulator Working Group Notice of Meeting AGENCY: The United States... Global Positioning Systems (GPS) Directorate will be hosting an open GPS Satellite Simulator Working Group (SSWG) meeting for manufacturers of GPS constellation simulators utilized by the federal...

  5. Use of Technology Global Positioning System (GPS) Receiver Garmin Etrex Vista as a Tool Navigation


    Paul Jabesh Supit Kilis; Fivtatianti H., SKom. MM Fivtatianti H., SKom. MM


    Global Positioning System (GPS) is a radio system navigation and positioningusing satellites. By using a GPS receiver, we can determine the position of ourexistence. The purpose of this paper is to use a GPS receiver as a navigational tool,which in this study used a GPS receiver is the Garmin eTrex Vista.

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

    Directory of Open Access Journals (Sweden)

    N. Jakowski

    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.

  7. GPs' perceptions of workload in England: a qualitative interview study. (United States)

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


    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.

  8. Using Transponders on the Moon to Increase Accuracy of GPS (United States)

    Penanen, Konstantin; Chui, Talso


    It has been proposed to place laser or radio transponders at suitably chosen locations on the Moon to increase the accuracy achievable using the Global Positioning System (GPS) or other satellite-based positioning system. The accuracy of GPS position measurements depends on the accuracy of determination of the ephemerides of the GPS satellites. These ephemerides are determined by means of ranging to and from Earth-based stations and consistency checks among the satellites. Unfortunately, ranging to and from Earth is subject to errors caused by atmospheric effects, notably including unpredictable variations in refraction. The proposal is based on exploitation of the fact that ranging between a GPS satellite and another object outside the atmosphere is not subject to error-inducing atmospheric effects. The Moon is such an object and is a convenient place for a ranging station. The ephemeris of the Moon is well known and, unlike a GPS satellite, the Moon is massive enough that its orbit is not measurably affected by the solar wind and solar radiation. According to the proposal, each GPS satellite would repeatedly send a short laser or radio pulse toward the Moon and the transponder(s) would respond by sending back a pulse and delay information. The GPS satellite could then compute its distance from the known position(s) of the transponder(s) on the Moon. Because the same hemisphere of the Moon faces the Earth continuously, any transponders placed there would remain continuously or nearly continuously accessible to GPS satellites, and so only a relatively small number of transponders would be needed to provide continuous coverage. Assuming that the transponders would depend on solar power, it would be desirable to use at least two transponders, placed at diametrically opposite points on the edges of the Moon disk as seen from Earth, so that all or most of the time, at least one of them would be in sunlight.

  9. GPS Technology for the Development of Business Information Systems


    Muresan, Mihaela


    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 d...

  10. Directional Networking in GPS Denied Environments - Time Synchronization (United States)


    Directional Networking in GPS Denied Environments—Time Synchronization Derya Cansever and Gilbert Green Army CERDEC Aberdeen Proving Ground MA...when GPS is not available. We show that the Fast RTSR algorithm allows the entire network to achieve time synchronization with convergence time of...RF-based measurements to synchronize time and measure node range.  Satellite Doppler: Using Doppler measurements from multiple satellites along

  11. GPs' approaches to documenting stigmatising information: a qualitative study. (United States)

    Dossa, Almas; Welch, Lisa C


    Complete medical documentation is essential for continuity of care, but the competing need to protect patient confidentiality presents an ethical dilemma. This is particularly poignant for GPs because of their central role in facilitating continuity. To examine how GPs manage medical documentation of stigmatising mental health (MH) and non-MH information. A qualitative sub-study of a factorial experiment with GPs practising in Massachusetts, US. Semi-structured interviews (n = 128) were audiorecorded and transcribed verbatim. Transcripts were coded and analysed for themes. GPs expressed difficulties with and inconsistent strategies for documenting stigmatising information. Without being asked directly about stigmatising information, 44 GPs (34%) expressed difficulties documenting it: whether to include clinically relevant but sensitive information, how to word it, and explaining to patients the importance of including it. Additionally, 75 GPs (59%) discussed strategies for managing documentation of stigmatising information. GPs reported four strategies that varied by type of information: to exclude stigmatising information to respect patient confidentiality (MH: 26%, non-MH: 43%); to include but restrict access to information (MH: 13%, non-MH: 25%); to include but neutralise information to minimise potential stigma (MH: 26%, non-MH: 29%); and to include stigmatising information given the potential impact on care (MH: 68%, non-MH: 32%). Lack of consistency undermines the potential of medical documentation to efficiently facilitate continuous, coordinated health care because providers cannot be certain how to interpret what is or is not in the chart. A proactive consensus process within the field of primary care would provide much needed guidance for GPs and, ultimately, could enhance quality of care. © British Journal of General Practice 2015.


    Directory of Open Access Journals (Sweden)

    D. Pandey


    Full Text Available With the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs, satellite navigation is undergoing drastic changes. Presently, more than 70 satellites are already available and nearly 120 more satellites will be available in the coming years after the achievement of complete constellation for all four systems- GPS, GLONASS, Galileo and BeiDou. The significant improvement in terms of satellite visibility, spatial geometry, dilution of precision and accuracy demands the utilization of combining multi-GNSS for Precise Point Positioning (PPP, especially in constrained environments. Currently, PPP is performed based on the processing of only GPS observations. Static and kinematic PPP solutions based on the processing of only GPS observations is limited by the satellite visibility, which is often insufficient for the mountainous and open pit mines areas. One of the easiest options available to enhance the positioning reliability is to integrate GPS and GLONASS observations. This research investigates the efficacy of combining GPS and GLONASS observations for achieving static PPP solution and its sensitivity to different processing methodology. Two static PPP solutions, namely standalone GPS and combined GPS-GLONASS solutions are compared. The datasets are processed using the open source GNSS processing environment gLAB 2.2.7 as well as magicGNSS software package. The results reveal that the addition of GLONASS observations improves the static positioning accuracy in comparison with the standalone GPS point positioning. Further, results show that there is an improvement in the three dimensional positioning accuracy. It is also shown that the addition of GLONASS constellation improves the total number of visible satellites by more than 60% which leads to the improvement of satellite geometry represented by Position Dilution of Precision (PDOP by more than 30%.

  13. GPS and Glonass Combined Static Precise Point Positioning (ppp) (United States)

    Pandey, D.; Dwivedi, R.; Dikshit, O.; Singh, A. K.


    With the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs), satellite navigation is undergoing drastic changes. Presently, more than 70 satellites are already available and nearly 120 more satellites will be available in the coming years after the achievement of complete constellation for all four systems- GPS, GLONASS, Galileo and BeiDou. The significant improvement in terms of satellite visibility, spatial geometry, dilution of precision and accuracy demands the utilization of combining multi-GNSS for Precise Point Positioning (PPP), especially in constrained environments. Currently, PPP is performed based on the processing of only GPS observations. Static and kinematic PPP solutions based on the processing of only GPS observations is limited by the satellite visibility, which is often insufficient for the mountainous and open pit mines areas. One of the easiest options available to enhance the positioning reliability is to integrate GPS and GLONASS observations. This research investigates the efficacy of combining GPS and GLONASS observations for achieving static PPP solution and its sensitivity to different processing methodology. Two static PPP solutions, namely standalone GPS and combined GPS-GLONASS solutions are compared. The datasets are processed using the open source GNSS processing environment gLAB 2.2.7 as well as magicGNSS software package. The results reveal that the addition of GLONASS observations improves the static positioning accuracy in comparison with the standalone GPS point positioning. Further, results show that there is an improvement in the three dimensional positioning accuracy. It is also shown that the addition of GLONASS constellation improves the total number of visible satellites by more than 60% which leads to the improvement of satellite geometry represented by Position Dilution of Precision (PDOP) by more than 30%.

  14. A New Geometric Trilateration Scheme for GPS-Style Localization (United States)

    Cheung, K.-M.; Lee, C.


    In this article, we introduce a new trilateration method for GPS-style localization. We show by simulations that the localization accuracy of the new method is indistinguishable from that of the traditional GPS approach. On the user segment side, the new scheme is computationally more efficient. This has the potential to translate into lower cost, and to enable faster location acquisition in the more challenging and dynamic operation environments.

  15. ISOLDE target zone GPS robot, Camera A Part1

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements along the corridor picking up an ISOLDE target from one of the shelfs behind the lead shielding doors and moving it to the exchange point. Several movements of the ISOLDE GPS robot from different angles with and without target along the corridor as well as posing and taking the target from the shelf and posing it onto the exchange point.

  16. ISOLDE target zone GPS robot, Camera A Part2 HD

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements along the corridor picking up an ISOLDE target from one of the shelfs behind the lead shielding doors and moving it to the exchange point. Several movements of the ISOLDE GPS robot from different angles with and without target along the corridor as well as posing and taking the target from the shelf and posing it onto the exchange point.

  17. ISOLDE target zone GPS robot, Camera A Part2

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements along the corridor picking up an ISOLDE target from one of the shelfs behind the lead shielding doors and moving it to the exchange point. Several movements of the ISOLDE GPS robot from different angles with and without target along the corridor as well as posing and taking the target from the shelf and posing it onto the exchange point.

  18. ISOLDE target zone GPS robot, Camera A Part1 HD

    CERN Multimedia


    Sequences of the ISOLDE GPS robot movements along the corridor picking up an ISOLDE target from one of the shelfs behind the lead shielding doors and moving it to the exchange point. Several movements of the ISOLDE GPS robot from different angles with and without target along the corridor as well as posing and taking the target from the shelf and posing it onto the exchange point.

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

    Directory of Open Access Journals (Sweden)

    N. Jakowski


    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.

  20. GPS Estimates of Integrated Precipitable Water Aid Weather Forecasters (United States)

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


    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.

  1. Inferring Directed Road Networks from GPS Traces by Track Alignment

    Directory of Open Access Journals (Sweden)

    Xingzhe Xie


    Full Text Available This paper proposes a method to infer road networks from GPS traces. These networks include intersections between roads, the connectivity between the intersections and the possible traffic directions between directly-connected intersections. These intersections are localized by detecting and clustering turning points, which are locations where the moving direction changes on GPS traces. We infer the structure of road networks by segmenting all of the GPS traces to identify these intersections. We can then form both a connectivity matrix of the intersections and a small representative GPS track for each road segment. The road segment between each pair of directly-connected intersections is represented using a series of geographical locations, which are averaged from all of the tracks on this road segment by aligning them using the dynamic time warping (DTW algorithm. Our contribution is two-fold. First, we detect potential intersections by clustering the turning points on the GPS traces. Second, we infer the geometry of the road segments between intersections by aligning GPS tracks point by point using a “stretch and then compress” strategy based on the DTW algorithm. This approach not only allows road estimation by averaging the aligned tracks, but also a deeper statistical analysis based on the individual track’s time alignment, for example the variance of speed along a road segment.

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

    Directory of Open Access Journals (Sweden)

    Koichiro Doi


    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.

  3. Kinematic GPS survey as validation of LIDAR strips accuracy

    Directory of Open Access Journals (Sweden)

    C. Gordini


    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.

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

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    Hasanuddin Z. Abidin


    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.

  5. Soil Moisture Retrieval Based on GPS Signal Strength Attenuation

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    Franziska Koch


    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.

  6. GPs' perceptions of resilience training: a qualitative study. (United States)

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


    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.

  7. Co-location of VLBI reference point and GPS permanent station using rapid static and kinematic GPS (United States)

    Negusini, M.; Sarti, P.; Sillard, P.; Tomasi, P.; Vittuari, L.


    During a one day measurement campaign carried out in 2001 and 2002, we used rapid static and kinematic GPS techniques in order to determine the reference point of the VLBI antenna situated at the radioastronomical observatory of Medicina. Triangulation and trilateration using high precision total stations have demonstrated millimetre accuracy but can be very time consuming. This latter approach also requires a complete inactivity of the VLBI antenna. We have therefore pursued the same task using GPS measurements, expecting lower precisions with respect to classical measurements, but allowing the determination in much shorter time. The use of absolute calibration of GPS antennae (GEO++ GNPCV DB) is tested and thanks to the statistical approach developed for classical measurements treatment (described in an a separate presentation) co-location between VLBI reference point and GPS permanent station was rigorously computed.

  8. Observation of landslide movement by GPS static survey; GPS sokuryo ni yoru jisuberi ido kansoku

    Energy Technology Data Exchange (ETDEWEB)

    Fukuoka, H. [Kyoto Univ., Kyoto (Japan). Disaster Prevention Research Inst.; Ezaki, T.; Kodama, N. [Fuken Co. Ltd., Hiroshima (Japan)


    This paper introduces results of mobile observations on landslides by using static GPS surveys in the Nuta{center_dot}Youne landslide area inKochi Prefecture and the Taguchi landslide area in Okayama Prefecture. Because the base line analysis was performed by using one frequency only although some receivers were of two-frequency corresponding type, all the analysis data are based on one frequency. Time bands in which signals can be received from more than four GPS satellites were selected in each observation, and the observations have lasted for 3 to 4 hours per session. The number of receivers used was four to six, although the number is not the same in each observation. Nominal accuracy for the receivers used was 5 mm + 2 ppm times the base line length. However, since the base line lengths used in the present observations were all less than 2 km, the error is about 9 mm at maximum. At the Nuta{center_dot}Youne landslide area, displacements of greater than 1.5 cm were observed at all the observation points. At the Taguchi landslide area, displacements from 2 to 3.5 cm were observed at all points. At bankings built relatively newly, it was observed that displacement of 5.5 cm was cumulated during the same observation time period, disclosing the necessity that some measures should be provided urgently. 8 refs., 7 figs.

  9. Optimization of GPS Interferometric Reflectometry for Remote Sensing (United States)

    Chen, Qiang

    GPS Interferometric Reflectometry (GPS-IR), a passive microwave remote sensing technique utilizing GPS signal as a source of opportunity, characterizes the Earth's surface through a bistatic radar configuration. The key idea of GPS-IR is utilizing a ground-based antenna to coherently receive the direct, or line-of-sight (LOS), signal and the Earth's surface reflected signal simultaneously. The direct and reflected signals create an interference pattern of the Signal-to-Noise Ratio (SNR), which contains the information about the Earth's surface environment. GPS-IR has proven its utility in a variety of environmental remote sensing applications, including the measurements of near-surface soil moisture, coastal sea level, snow depth and snow water equivalent, and vegetation biophysical parameters. A major approach of the GPS-IR technique is using the SNR data provided by the global network of the geodetic GPS stations deployed for tectonic and surveying applications. The geodetic GPS networks provide wide spatial coverage and have no additional cost for this capability expansion. However, the geodetic GPS instruments have intrinsic limitations: the geodetic-quality GPS antennas are designed to suppress the reflected signals, which is counter to the requirement of GPS-IR. As a result, it is desirable to refine and optimize the instrument and realize the full potential of the GPS-IR technique. This dissertation first analyzes the signal characteristics of four available polarizations of the GPS signal, and then discusses how these characteristics are related to and can be used for remote sensing applications of GPS-IR. Two types of antennas, a half-wavelength dipole antenna and a patch antenna, are proposed and fabricated to utilize the desired polarizations. Four field experiments are conducted to assess the feasibility of the design criteria and the performance of the proposed antennas. Three experiments are focused on snow depth measurement. The Table Mountain

  10. Status of Precise Orbit Determination for Jason-2 Using GPS (United States)

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Ludwig Combrinck


    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.

  12. Can RTK GPS be Used to Improve Cadastral Infrastructure?

    Directory of Open Access Journals (Sweden)

    Craig Roberts


    Full Text Available Cadastral surveying is concerned with the process of gathering evidence in the form of position information that is used to define the location of objects or land boundaries for the purposes of identifying ownership and/or the value of land parcels. The advent of Global Navigation Satellite Systems (GNSS, such as the Global Positioning System (GPS, has revolutionised the way 3-dimensional positions are determined and GPS surveying techniques, particularly Real Time Kinematic (RTK, are increasingly being adopted by cadastral surveyors. This paper presents a methodology for using RTK GPS observations to improve the existing cadastral survey control infrastructure, based on an extensive survey carried out in New South Wales, Australia. It is shown that accuracies (RMS of 11 mm in the horizontal and 34 mm in the vertical component (1? can be achieved for this dataset. Calculated bearings and distances agree very well with the official values derived from the state’s survey control database, easily meeting accuracy specifications and survey regulation requirements. 55% of the unestablished marks surveyed were able to be upgraded to cadastral survey control quality. Enhancements in the GPS survey design would have enabled an even higher percentage of marks to be classified as established, showing that the RTK GPS technique is well suited to improving survey control infrastructure for cadastral surveyors.

  13. Impacts of Stochastic Modeling on GPS-derived ZTD Estimations

    CERN Document Server

    Jin, Shuanggen


    GPS-derived ZTD (Zenith Tropospheric Delay) plays a key role in near real-time weather forecasting, especially in improving the precision of Numerical Weather Prediction (NWP) models. The ZTD is usually estimated using the first-order Gauss-Markov process with a fairly large correlation, and under the assumption that all the GPS measurements, carrier phases or pseudo-ranges, have the same accuracy. However, these assumptions are unrealistic. This paper aims to investigate the impact of several stochastic modeling methods on GPS-derived ZTD estimations using Australian IGS data. The results show that the accuracy of GPS-derived ZTD can be improved using a suitable stochastic model for the GPS measurements. The stochastic model using satellite elevation angle-based cosine function is better than other investigated stochastic models. It is noted that, when different stochastic modeling strategies are used, the variations in estimated ZTD can reach as much as 1cm. This improvement of ZTD estimation is certainly c...

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

    Directory of Open Access Journals (Sweden)

    Pedro S. A. Wolf


    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

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

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    WU Dongdong


    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.

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

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    T. Schöne


    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.

  17. Ethics support for GPs: what should it look like? (United States)

    Clark-Grill, Monika


    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.

  18. Using the GPS SNR Technique to Detect Volcanic Plumes (United States)

    Naik, S. R.; Mattia, M.; Larson, K. M.; Rossi, M.; Bruno, V.; Coltelli, M.; Ohta, Y.; Schneider, D. J.


    Detection of volcanic plumes, especially ash-laden ones, is important both for public health and aircraft safety. A variety of geophysical tools and satellite data are used to monitor volcanic eruptions and to predict the movement of ash. However, satellite-based methods are restricted by time of day and weather, while radars are often unavailable because of cost/ portability. GPS instruments are frequently deployed near volcanos, but typically they have only been used to measure deformation. Here a method is proposed to detect volcanic plumes using GPS signal to noise ratio (SNR) data. The strengths and limitations of the method are assessed using GPS data collected during eruptions at Mt. Redoubt (2009) and Mt. Etna (2013). Plume detections are compared with independently collected seismic and radar data.


    Directory of Open Access Journals (Sweden)

    W. A. W. Aris


    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.

  20. How GPs implement clinical guidelines in everyday clinical practice

    DEFF Research Database (Denmark)

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


    . 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......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...

  1. Enjoying a healthy pregnancy: GPs' essential role in health promotion. (United States)

    Frayne, Jacqueline; Hauck, Yvonne

    For many women, a major pregnancy goal is to achieve an enjoyable, healthy pregnancy. The continuum of care from preconception counselling, management of early pregnancy, referral or continued pregnancy care and management into the postpartum period places general practitioners (GPs) in a unique position to meaningfully contribute on many levels to this realisation. The aim of this article is to explore the determinants of a healthy and enjoyable pregnancy, and asks how GPs can facilitate an optimum experience for women in pregnancy, regardless of risk. GPs can play a key role with prospective parents in health promotion, directing them to appropriate resources and services; addressing disease prevention by targeting modifiable lifestyle risks; and managing chronic health concerns in the optimisation of pregnancy care.

  2. Reduction Vehicle Speed Using GPS Android Smart Phone Programming

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    Sameer Sami Hassan


    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.

  3. Global GPS Ionospheric Modelling Using Spherical Harmonic Expansion Approach

    Directory of Open Access Journals (Sweden)

    Byung-Kyu Choi


    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.

  4. GPS based three-dimensional ionospheric monitoring: procedure and assessment (United States)

    Stolle, C.; Schlüter, S.; Heise, S.; Jacobi, Ch.; Jakowski, N.; Raabe, A.

    Integrated TEC measurements derived from ground- and space-based GPS observations are used to image the ionospheric electron density distribution through three-dimensional tomographic reconstruction. Here, the reconstruction procedure is presented, that has been applied for ionospheric mapping especially during perturbed geomagnetic conditions. The monitoring technique including tomographic algorithm and external constraints is described and discussed in detail. The procedure is based on an iterative MART algorithm and is initialised by a combined IRI/GCPM model. Input data are GPS TEC measured from ground-based networks as well as from the scientific Low Earth Orbiting (LEO) satellite CHAMP. The problem of spaceborne GPS instrumental biases is addressed, and the approach applied for bias estimation by using calibrated zenith antenna TEC data is presented. Statistical validations of tomographic results with independent data are shown.

  5. Validation of GPS and accelerometer technology in swimming. (United States)

    Beanland, Emma; Main, Luana C; Aisbett, Brad; Gastin, Paul; Netto, Kevin


    To evaluate the validity of an integrated accelerometer and Global Positioning System (GPS) device to quantify swimming kinematics variables in swimming. Criterion validation study. Twenty-one sub-elite swimmers completed three 100 m efforts (one butterfly, breaststroke and freestyle) in an outdoor 50 m Olympic pool. A GPS device with an integrated tri-axial accelerometer was used to obtain mid-pool velocity and stroke count of each effort. This data was compared to velocity and stroke count data obtained from concurrently recorded digital video of the performance. A strong relationship was detected between the accelerometer stroke count and the video criterion measure for both breaststroke (r>0.98) and butterfly (r>0.99). Also, no significant differences were detected between the GPS velocity and video obtained velocity for both freestyle and breaststroke. There was a significant difference between the GPS velocity and criterion measure for butterfly. Acceptable standard error and 95% limits of agreement were obtained for freestyle (0.13 m s(-1), 0.36 m s(-1)) and breaststroke (0.12 m s(-1), 0.33 m s(-1)) compared to butterfly (0.18 m s(-1), 0.50 m s(-1)). Relative error measurements ranged between 10.2 and 13.4% across the three strokes. The integrated accelerometer and GPS device offers a valid and accurate tool for stroke count quantification in breaststroke and butterfly as well as measuring mid-pool swimming velocity in freestyle and breaststroke. The application of GPS technology in the outdoor training environment suggests advantageous practical benefits for swimmers, coaches and sports scientists. Copyright © 2013 Sports Medicine Australia. All rights reserved.

  6. Investigating Atmospheric Rivers using GPS PW from Ocean Transits (United States)

    Almanza, V.; Foster, J. H.; Businger, S.


    Atmospheric Rivers (AR) can be described as a long narrow feature within a warm conveyor belt where anomalous precipitable water (PW) is transported from low to high latitudes. Close monitoring of ARs is heavily reliant on satellites, which are limited both in space and time, to capture the fluctuations PW particularly over the ocean. Ship-based Global Positioning System (GPS) receivers have been successful in obtaining millimeter PW accuracy within 100 km from the nearest ground-based reference receiver at a 30 second sampling rate. We extended this capability with a field experiment using ship-based GPS PW on board a cargo ship to traverse over the Eastern Pacific Ocean. In one 14-day cruise cycle, between the periods of February 3-16, 2014, the ship-based GPS captured PW spikes >50 mm during the early development of two ARs, which lead to moderate to heavy rainfall events for Hawaii and flood conditions along the West Coast of the United States. Comparisons between PW solutions processed using different GPS reference sites at distances 100-2000 km provided an internal validation for the ship-based GPS PW with errors typically less than 5 mm. Land-based observations provided an external validation and are in good agreement with ship-based GPS PW at distances cost-effective approach for acquiring continuous meteorological observations over the oceans, which can provide important calibration/validation data for satellite retrieval algorithms. Ship-based systems could be particularly useful for augmenting our meteorological observing networks to improve weather prediction and nowcasting, which in turn provide critical support for hazard response and mitigation efforts in coastal regions.

  7. [Good Practice of Secondary Data Analysis (GPS): guidelines and recommendations]. (United States)

    Swart, E; Gothe, H; Geyer, S; Jaunzeme, J; Maier, B; Grobe, T G; Ihle, P


    In 2005, the Working Group for the Survey and Utilisation of Secondary Data (AGENS) of the German Society for Social Medicine and Prevention (DGSMP) and the German Society for Epidemiology (DGEpi) first published "Good Practice in Secondary Data Analysis (GPS)" formulating a standard for conducting secondary data analyses. GPS is intended as a guide for planning and conducting analyses and can provide a basis for contracts between data owners. The domain of these guidelines does not only include data routinely gathered by statutory health insurance funds and further statutory social insurance funds, but all forms of secondary data. The 11 guidelines range from ethical principles and study planning through quality assurance measures and data preparation to data privacy, contractual conditions and responsible communication of analytical results. They are complemented by explanations and practical assistance in the form of recommendations. GPS targets all persons directing their attention to secondary data, their analysis and interpretation from a scientific point of view and by employing scientific methods. This includes data owners. Furthermore, GPS is suitable to assess scientific publications regarding their quality by authors, referees and readers. In 2008, the first version of GPS was evaluated and revised by members of AGENS and the Epidemiological Methods Working Group of DGEpi, DGSMP and GMDS including other epidemiological experts and had then been accredited as implementation regulations of Good Epidemiological Practice (GEP). Since 2012, this third version of GPS is on hand and available for downloading from the DGEpi website at no charge. Especially linguistic specifications have been integrated into the current revision; its internal consistency was increased. With regards to contents, further recommendations concerning the guideline on data privacy have been added. On the basis of future developments in science and data privacy, further revisions will

  8. Thermospheric neutral densities derived from Swarm accelerometer and GPS data

    DEFF Research Database (Denmark)

    Doornbos, Eelco; Encarnacao, Joao; van den IJss, Jose

    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...... data from the Swarm GPS observations only, with a much lower temporal resolution. We analyse the differences in the data between the three Swarm satellites as well as between the accelerometer-derived and GPS-only-derived densities for Swarm C....

  9. GPS as local geological control and national geodetic control (United States)

    Cross, P. A.; Sellers, P. C.

    In June 1987 GPS surveys were carried out around six Greek SLR sites. These sites are part of the WEGENER/MEDLAS network in the Eastern Mediterranean region. In a three week campaign six small fiducial networks, typically 5-10 km, were successfully surveyed. Results show that the local geological stability of a SLR site can easily be monitored at the (sub)centimetre level. Since the fiducial networks included Greek national triangulation pillars, GPS also proved to be an efficient tool for tying the zero-order SLR (baseline) network to the national control network.

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

    Directory of Open Access Journals (Sweden)

    S. Gandolfi


    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.

  11. Ionospheric corrections to precise time transfer using GPS (United States)

    Snow, Robert W.; Osborne, Allen W., III; Klobuchar, John A.; Doherty, Patricia H.


    The free electrons in the earth's ionosphere can retard the time of reception of GPS signals received at a ground station, compared to their time in free space, by many tens of nanoseconds, thus limiting the accuracy of time transfer by GPS. The amount of the ionospheric time delay is proportional to the total number of electrons encountered by the wave on its path from each GPS satellite to a receiver. This integrated number of electrons is called Total Electron Content, or TEC. Dual frequency GPS receivers designed by Allen Osborne Associates, Inc. (AOA) directly measure both the ionospheric differential group delay and the differential carrier phase advance for the two GPS frequencies and derive from this the TEC between the receiver and each GPS satellite in track. The group delay information is mainly used to provide an absolute calibration to the relative differential carrier phase, which is an extremely precise measure of relative TEC. The AOA Mini-Rogue ICS-4Z and the AOA TurboRogue ICS-4000Z receivers normally operate using the GPS P code, when available, and switch to cross-correlation signal processing when the GPS satellites are in the Anti-Spoofing (A-S) mode and the P code is encrypted. An AOA ICS-Z receiver has been operated continuously for over a year at Hanscom AFB, MA to determine the statistics of the variability of the TEC parameter using signals from up to four different directions simultaneously. The 4-channel ICS-4Z and the 8-channel ICS-4000Z, have proven capabilities to make precise, well calibrated, measurements of the ionosphere in several directions simultaneously. In addition to providing ionospheric corrections for precise time transfer via satellite, this dual frequency design allows full code and automatic codeless operation of both the differential group delay and differential carrier phase for numerous ionospheric experiments being conducted. Statistical results of the data collected from the ICS-4Z during the initial year of

  12. Latest trends in the GPS measurements technologies - twilight of geodesy ?

    Directory of Open Access Journals (Sweden)

    Martin Kalafut


    Full Text Available Nowadays, more and more sophisticated GPS measurement technologies offer, on one side, a straightforward simplification, robust integrated surveying and a large scale automatization of measurement methods in the field. On the other side, they become a new challenge for the qualified geodetical public that are faced with consequencies derived from this fact. First of all - the real danger of loss of the importancy of qualified geodetical education in conjunction with the practical use of latest GPS measurement technologies is the most crucial consequency. The main goal of the paper is to stimulate a serious discussion on this topic.

  13. GPS (Global Positioning System) Data Link for Test and Training (United States)


    exercisej. Virst, because GPS -ill be world-wide, the range need I not be tied to a specific piece of real estate ; variety in training is thus; muc...terminal as well. The data bus thus provides a menas for solving two prcblems associated with the use of operational aircraft in tests and instrýA... real -time or near real -time player positions would p..obably be required; this, in turn, would "probably require a GPS set at the range receiving station

  14. Glasgow Prognostic Score (GPS) can be a useful indicator to determine prognosis of patients with colorectal carcinoma. (United States)

    Nozoe, Tadahiro; Matono, Rumi; Ijichi, Hideki; Ohga, Takefumi; Ezaki, Takahiro


    The Glasgow Prognostic Score (GPS), an inflammation-based score, has been used to predict the biologic behavior of malignant tumors. The aim of the current study was to elucidate a further significance of GPS in colorectal carcinoma. Correlation of GPS and modified GPS (mGPS), which are composed of combined score provided for serum elevation of C-reactive protein and hypoalbuminemia examined before surgical treatment, with clinicopathologic features was investigated in 272 patients with colorectal carcinoma. Survival of GPS 1 patients was significantly worse than that of GPS 0 patients (P= 0.009), and survival of GPS 2 patients was significantly worse than that of GPS 1 patients (P GPS (P GPS and mGPS could classify outcome of patients with a clear stratification, and could be applied as prognostic indicators in colorectal carcinoma.

  15. 77 FR 16860 - Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of... (United States)


    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain GPS Navigation Products, Components Thereof, and Related Software; Termination of... within the United States after importation of certain GPS navigation products, components thereof, and...

  16. IceBridge GPS L0 Raw Satellite Navigation Data, Version 1 (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,...

  17. 77 FR 13350 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same... (United States)


    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same... importation of certain automotive GPS navigation systems, components thereof, and products containing the same...

  18. 77 FR 35428 - Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same... (United States)


    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Automotive GPS Navigation Systems, Components Thereof, and Products Containing Same... importation of certain automotive GPS navigation systems, components thereof, and products containing the same...

  19. Influences on GPs' decision to prescribe new drugs-the importance of who says what

    National Research Council Canada - National Science Library

    Prosser, Helen; Almond, Solomon; Walley, Tom


    The aim of this study was to understand the range of factors that influence GPs' uptake of new drugs A total of 107 GPs selected purposively from high, medium and low new drug prescribing practices...

  20. Part 3: GPS Telemetry Detection Rates (Probability), GCS NAD83 (2015) (United States)

    U.S. Geological Survey, Department of the Interior — Bias correction in GPS telemetry datasets requires a strong understanding of the mechanisms that result in missing data. We tested wildlife GPS collars in a variety...

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

    Index Scriptorium Estoniae

    Filippov, Madis


    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

  2. IceBridge L0 Raw Kinematics GPS Time Codes, Version 1 (United States)

    National Aeronautics and Space Administration — The NASA IceBridge L0 Raw Kinematics GPS Time Codes (ITKTC0) data set contains time codes generated during flights over Antarctica using the TrueTime 705-101 GPS...

  3. Effects of GPS sampling intensity on home range analyses (United States)

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


    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...

  4. GPS/MEMS IMU/Microprocessor Board for Navigation (United States)

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


    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.

  5. 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 ...

  6. Jason-1 and Jason-2 POD Using GPS (United States)

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


    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.

  7. GPS: Shaping Student Success One Conversation at a Time (United States)

    Star, Mikhael; Collette, Lanita


    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…

  8. IMU/GPS System Provides Position and Attitude Data (United States)

    Lin, Ching Fang


    A special navigation system is being developed to provide high-quality information on the position and attitude of a moving platform (an aircraft or spacecraft), for use in pointing and stabilization of a hyperspectral remote-sensing system carried aboard the platform. The system also serves to enable synchronization and interpretation of readouts of all onboard sensors. The heart of the system is a commercially available unit, small enough to be held in one hand, that contains an integral combination of an inertial measurement unit (IMU) of the microelectromechanical systems (MEMS) type, Global Positioning System (GPS) receivers, a differential GPS subsystem, and ancillary data-processing subsystems. The system utilizes GPS carrier-phase measurements to generate time data plus highly accurate and continuous data on the position, attitude, rotation, and acceleration of the platform. Relative to prior navigation systems based on IMU and GPS subsystems, this system is smaller, is less expensive, and performs better. Optionally, the system can easily be connected to a laptop computer for demonstration and evaluation. In addition to airborne and spaceborne remote-sensing applications, there are numerous potential terrestrial sensing, measurement, and navigation applications in diverse endeavors that include forestry, environmental monitoring, agriculture, mining, and robotics.

  9. A New Indoor Positioning System Architecture Using GPS Signals

    Directory of Open Access Journals (Sweden)

    Rui Xu


    Full Text Available 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.

  10. A Comparative Study on Position Fixing with GPS to Ascertain ...

    African Journals Online (AJOL)

    Ghana Mining Journal ... Continuous Observation Reference Station (CORS) is one of the latest techniques employed in differential GPS positioning. ... Eastings coordinates obtained from the temporarily occupied reference station compares favourably with those of the conventional method and the CORS with variations in ...

  11. Utilization of GPS Tropospheric Delays for Climate Research (United States)

    Suparta, Wayan


    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.

  12. Characterization of Periodic Variations in the GPS Satellite Clocks (United States)


    Transfer and Time Scale Formation,” Metrologia 40, S270-S288. Ray, J.R., and K.L. Senior, 2005, “Geodetic Techniques for Time and Frequency...Comparisons Using GPS Phase and Code Measurements,” Metrologia 42, 215-232. Rochat, P., F. Droz, P. Mosset, G. Barmaverain, Q. Wang, D. Boving, L

  13. Time and Frequency Transfer Combining GLONASS and GPS Data (United States)


    USA (IEEE), pp. 334-356. [2] D. W. Allan and C. Thomas, 1994, “Technical directives for standardization of GPS time receiver software,” Metrologia ...Defraigne and G. Petit, 2003, “Time Transfer to TAI Using Geodetic Receivers,” Metrologia , 40, 184-188. [5] P. Defraigne and G. Petit, 2001, “Proposal

  14. Time Transfer from Combined Analysis of GPS and TWSTFT Data (United States)


    Koudelka, 2008, “Time transfer with nanosecond accuracy for the realization of International Atomic Time,” Metrologia , 45, 185- 198. [6] G. Petit and Z...K. Senior, 2005, “Geodetic techniques for time and frequency comparisons using GPS phase and code measurements,” Metrologia , 42, 215-232. [11] J

  15. Troposphere Modeling and Filtering for Precise GPS Leveling

    NARCIS (Netherlands)

    Kleijer, F.


    Precise height differences (5--10 mm standard deviation) are of interest for applications such as maintenance of the Amsterdam Ordnance Datum and deformation analysis. For these applications the Global Positioning System (GPS) is a cost-effective alternative for classic leveling techniques. However,

  16. Software for a GPS-Reflection Remote-Sensing System (United States)

    Lowe, Stephen


    A special-purpose software Global Positioning System (GPS) receiver designed for remote sensing with reflected GPS signals is described in Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System (NPO-30385), which appears elsewhere in this issue of NASA Tech Briefs. The input accepted by this program comprises raw (open-loop) digitized GPS signals sampled at a rate of about 20 MHz. The program processes the data samples to perform the following functions: detection of signals; tracking of phases and delays; mapping of delay, Doppler, and delay/Doppler waveforms; dual-frequency processing; coherent integrations as short as 125 s; decoding of navigation messages; and precise time tagging of observable quantities. The software can perform these functions on all detectable satellite signals without dead time. Open-loop data collected over water, land, or ice and processed by this software can be further processed to extract geophysical information. Possible examples include mean sea height, wind speed and direction, and significant wave height (for observations over the ocean); bistatic-radar terrain images and measures of soil moisture and biomass (for observations over land); and estimates of ice age, thickness, and surface density (for observations over ice).

  17. Value of histopathologic analysis of skin excisions by GPs

    NARCIS (Netherlands)

    Buis, P.A.J.; Chorus, R.M.; van Diest, P.J.


    The clinical diagnoses of skin lesions in general practice may sometimes not be very accurate. The aim of this study was to compare clinical versus final histopathological diagnosis status (benign, pre-malignant/malignant) in 4595 consecutive submissions by GPs. The final diagnosis was pre-malignant

  18. Android App Based Vehicle Tracking Using GPS And GSM

    Directory of Open Access Journals (Sweden)

    Jessica Saini


    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.

  19. Evaluation of EGM2008 by means of GPS Levelling Uganda

    African Journals Online (AJOL)


    frame using IGS orbit product precise ephemeris. GAMIT is a collection of programs to process GPS phase data to estimate three-dimensional relative positions of ground stations and satellite orbits, atmospheric zenith delays, and earth orientation parameters ( To control processing, the software ...

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

    Indian Academy of Sciences (India)

    resolve the dependence on the initial values for those voxels without any GPS rays traversing them. ... the integral of IED between satellite-receiver ray paths. ... when the ith voxel does not lie the same layer with the jth voxel, so wi = 0, on the contrary, the weight coefficient can be computed using the following equation wi =.

  1. Airborne Pseudolites in a Global Positioning System (GPS) Degraded Environment (United States)


    of the ION GPS 2000 Meeting. School of Geomatic Engineering University of New South Wales, Sydney, NSW 2052, Australia, September 2000. 95 12...56, July 2002. 35. Wang, Jinling and Hung-Kyu Lee. “Impact of Pseudolite Location Errors in Positioning”. Geomatics Research Australasia, 81–94

  2. Prophylactic treatment of migraine by GPs: a qualitative study

    NARCIS (Netherlands)

    Dekker, F.; Neven, A.K.; Andriesse, B.; Kernick, D.; Ferrari, M.D.; Assendelft, W.J.J.


    BACKGROUND: Despite the considerable impact of migraine, the use of preventive medication in primary care is limited. Only about 5% of migraine patients who qualify for prophylaxis actually receive it, and adherence is far from optimal. AIM: To explore the opinions of GPs regarding preventive

  3. 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


    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

  4. Which literature retrieval method is most effective for GPs?

    NARCIS (Netherlands)

    Verhoeven, A.A.H.; Boerma, E.J.; Meyboom-de Jong, B.

    Background. Evidence-based medicine requires new skills of physicians, including literature searching. Objective. To determine which literature retrieving method is most effective for GPs: the printed Index Medicus; Medline through Grateful Med; or Medline on CD-ROM. Methods. The design was a

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

    Directory of Open Access Journals (Sweden)

    Weiming Kuang


    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.

  6. A note on the delay distribution in GPS

    NARCIS (Netherlands)

    P.M.D. Lieshout (Pascal); M.R.H. Mandjes (Michel)


    textabstractIn this note a two-class Generalized Processor Sharing (GPS) system is considered. We analyze the probability that the virtual delay of a particular class exceeds some threshold. We apply Schilder's theorem to calculate the logarithmic many-sources asymptotics of this probability in the

  7. A note on the delay distribution in GPS

    NARCIS (Netherlands)

    Lieshout, P.; Mandjes, M.


    In this note a two-class generalized processor sharing (GPS) system is considered. We analyze the probability that the virtual delay of a particular class exceeds some threshold. We apply Schilder's theorem to calculate the logarithmic many-sources asymptotics of this probability in the important

  8. Cell jammers, GPS jammers, and other jamming devices. (United States)


    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...

  9. Arctic Tides from GPS on sea-ice

    DEFF Research Database (Denmark)

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


    ) placed on sea-ice, at six different sites north of Greenland for the preliminary study of sea surface height (SSH), and tidal analysis to improve tide models in the Central Arctic. The GPS measurements are compared with the Arctic tide model AOTIM-5, which assimilates tide-gauges and altimetry data...

  10. GPS based TEC measurements for a period August 2008 ...

    Indian Academy of Sciences (India)

    To study the variation in ionospheric TEC, we used the data obtained from GPS Ionospheric Scintillation and TEC monitoring (GISTM) system which is in operation at SVNIT, Surat, India (21.16°N, 72.78°E) located at the northern crest of equatorial anomaly region. The data collected (for the low sunspot activity period from ...

  11. A comparison of Google Earth extracted points with GPS surveyed ...

    African Journals Online (AJOL)

    Google Earth, virtual globe uses World Geodetic Coordinate System 1984 WGS84 as a global coordinate system. However, in this research, the transformations made from those data obtained using Global Positioning Systems (GPS) and those obtained from Google Earth were made and analyzed. The same points were ...

  12. DOC questionnaire : measuring how GPs and medical specialists rate collaboration

    NARCIS (Netherlands)

    Berendsen, A.J.; Benneker, W.H.; Groenier, K.H.; Schuling, J.; Grol, R.P.; Meyboom-de Jong, B.


    PURPOSE: This paper aims to assess the validity of a questionnaire aimed at assessing how general practitioners (GPs) and specialists rate collaboration. DESIGN/METHODOLOGY/APPROACH: Primary data were collected in The Netherlands during March to September 2006. A cross-sectional study was conducted

  13. DOC questionnaire: measuring how GPs and medical specialists rate collaboration.

    NARCIS (Netherlands)

    Berendsen, A.J.; Benneker, W.H.; Groenier, K.H.; Schuling, J.; Grol, R.P.T.M.; Meyboom-de Jong, B.


    PURPOSE: This paper aims to assess the validity of a questionnaire aimed at assessing how general practitioners (GPs) and specialists rate collaboration. DESIGN/METHODOLOGY/APPROACH: Primary data were collected in The Netherlands during March to September 2006. A cross-sectional study was conducted

  14. GPS scintillations associated with cusp dynamics and polar cap patches (United States)

    Jin, Yaqi; Moen, Jøran I.; Oksavik, Kjellmar; Spicher, Andres; Clausen, Lasse B. N.; Miloch, Wojciech J.


    This paper investigates the relative scintillation level associated with cusp dynamics (including precipitation, flow shears, etc.) with and without the formation of polar cap patches around the cusp inflow region by the EISCAT Svalbard radar (ESR) and two GPS scintillation receivers. A series of polar cap patches were observed by the ESR between 8:40 and 10:20 UT on December 3, 2011. The polar cap patches combined with the auroral dynamics were associated with a significantly higher GPS phase scintillation level (up to 0.6 rad) than those observed for the other two alternatives, i.e., cusp dynamics without polar cap patches, and polar cap patches without cusp aurora. The cusp auroral dynamics without plasma patches were indeed related to GPS phase scintillations at a moderate level (up to 0.3 rad). The polar cap patches away from the active cusp were associated with sporadic and moderate GPS phase scintillations (up to 0.2 rad). The main conclusion is that the worst global navigation satellite system space weather events on the dayside occur when polar cap patches enter the polar cap and are subject to particle precipitation and flow shears, which is analogous to the nightside when polar cap patches exit the polar cap and enter the auroral oval.

  15. Development and Validation of the Game Perception Scale (GPS) (United States)

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


    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,…

  16. On processing GPS tracking data of spatiotemporal car movements : a case study


    Zhao, Xiaoyun


    The advancement of GPS technology has made it possible to use GPS devices as orientation and navigation tools, but also as tools to track spatiotemporal information. GPS tracking data can be broadly applied in location-based services, such as spatial distribution of the economy, transportation routing and planning, traffic management and environmental control. Therefore, knowledge of how to process the data from a standard GPS device is crucial for further use. Previous studies have considere...

  17. Prevalence and predictors of occupational violence and aggression towards GPs: a cross-sectional study


    Koritsas, Stella; Coles, Jan; Boyle, Malcolm; Stanley, Janet


    Occupational violence and aggression are common in general practice. This study examined occupational violence and aggression against GPs in terms of prevalence and predictive factors, such as sex of GP and practice location. Over half of the GPs sampled had experienced at least one form of violence and aggression; more female than male GPs experienced sexual harassment; and there was no difference in the number of metropolitan and rural GPs who had experienced violence and aggression. Predic...

  18. The Lorca Earthquake observed by GPS: a Test Case for GPS Seismology

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, L.; Kehm, A.; Koppert, A.; Martin Dvaila, J.; Garate, J.; Becker, M.


    1 Hz GPS data recorded by the GNSS network of the Consejeria de Agricultura y Agua of the Murcia Region during the Mw 5.1 Lorca earthquake on May 11th 2011 is used as a test case. A Precise Point Positioning (PPP) approach is applied to analyse the earthquake-induced motion of the station LORC, located close to the epicenter. The results are validated using a conventional Double Differences (DD) processing. After applying sidereal and regional filters, the detected transient motion is about 20 millimeters in each component and clearly above noise level. The results from the two different processings are compared in view of the accuracy and applicability. The PPP approach described here can potentially be used for real-time analysis e.g. based on NTRIP streaming data. It may be used to set up an early warning system, as well as to gain real-time knowledge of ongoing earthquakes, extending the already-existing seismic information obtained from classical measurements. (Author) 33 refs.

  19. Vibrations of an ice-tongue using GPS records (United States)

    Lescarmontier, Lydie; Legrésy, Benoit; Coleman, Richard; Young, Neal; Testut, Laurent


    In November 2007, during the IPEV R0 Astrolabe voyage, we deployed a network of year-round GPS beacons along a flow line of the Mertz glacier in East Antarctica (CRAC-ICE project, Legrésy et al.). Two months of GPS data were collected at the end of the field season from 2 stations (GPS4 & GPS5) around the main rift on the Mertz floating ice tongue. We investigate sub daily time scales of motion of the two sites using the GPS records. The observed vertical signal includes tides, but also more rapid signals at sub-hourly time scales. With GPS processing using Gins-PC software and Precise Point Positioning processing (PPP); we are able to confirm getting the sub hourly scale oscillations of the ice tongue with few centimeters amplitude from two different part of the floating ice tongue. One mechanism in calving events is ocean wave energy, which leads to the movement of the ice tongue. The glacier then acts like a filter, with filtering characteristics depending mainly of the ice thickness (Holsworth and Gynn 1981). If a dominant frequency of the ocean wave spectrum coincides with one of the fundamental vibration modes of the ice-tongue, cyclic bending stresses may lead to fatigue of the ice and hence to crack propagation. This kind of event is a good candidate to explain a part of a calving process of an ice-tongue. Therefore, we focused of these oscillations using Harmonic analysis, short term FFT and wavelets. We identified a main energetic mode of vibrations around 10-40 minutes (23% of the total energy of the signal) that we compared with simple modeling of the fundamental vibrations of a beam. The model has been run in different cases of ice thickness, ice-tongue length and directions of the observed vibrations. The most visible oscillations correspond to a main mode of vibration propagating in the across flow direction of the ice tongue, driven mostly by ocean forcing. Both GPS sites are recording these vibrations. Given that each beacon is situated on from

  20. Characteristics and Limitations of Submerged GPS L1 Observations (United States)

    Steiner, Ladina; Geiger, Alain


    Extensive amount of water stored in snow covers has a high impact on flood development during snow melting periods. Early assessment of these parameters in mountain environments enhance early-warning and thus prevention of major impacts. Sub-snow GNSS techniques are lately suggested to determine liquid water content, snow water equivalent or considered for avalanche rescue. This technique is affordable, flexible, and provides accurate and continuous observations independent on weather conditions. However, the characteristics of GNSS observations for applications within a snow-pack still need to be further investigated. The magnitude of the main interaction processes involved for the GPS wavelength propagating through different layers of snow, ice or water is theoretically examined. Liquid water exerts the largest influence on GPS signal propagation through a snow-pack. Therefore, we focus on determining the characteristics of GNSS observables under water. An experiment was set-up to investigate the characteristics and limitations of submerged GPS observations using a pool, a level control by communicating pipes, a geodetic and a low-cost GPS antenna, and a water level sensor. The GPS antennas were placed into the water. The water level was increased daily by a step of two millimeters up to thirty millimeters above the antenna. Based on this experiment, the signal penetration depth, satellite availability, the attenuation of signal strength and the quality of solutions are analyzed. Our experimental results show an agreement with the theoretically derived attenuation parameter and signal penetration depth. The assumption of water as the limiting parameter for GPS observations within a snow-pack can be confirmed. Higher wetness in a snow-pack leads to less transmission, higher refraction, higher attenuation and thus a decreased penetration depth as well as a reduced quality of the solutions. In consequence, GPS applications within a snow-pack are heavily impacted by

  1. Retained satellite information influences performance of GPS devices in a forested ecosystem (United States)

    Katie M. Moriarty; Clinton W. Epps


    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...

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

    NARCIS (Netherlands)

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


    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

  3. 76 FR 27744 - Eighty-Fifth Meeting: RTCA Special Committee 159: Global Positioning System (GPS) (United States)


    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning 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). DATES: The meeting...

  4. 75 FR 61818 - Eighty-Third Meeting: RTCA Special Committee 159: Global Positioning System (GPS). (United States)


    ... System (GPS). AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning 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). DATES: The...

  5. 76 FR 67019 - Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS) (United States)


    ... Federal Aviation Administration Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS... RTCA Special Committee 159 meeting: Global Positioning 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...

  6. 76 FR 33022 - Eighty-Sixth Meeting: RTCA Special Committee 159: Global Positioning System (GPS) (United States)


    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning 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). DATES: The meeting...

  7. 77 FR 25150 - GPS Satellite Simulator Working Group; Notice of Meeting (United States)


    ... 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 published on April 20, 2012...

  8. 75 FR 2581 - Eighty-First Meeting: RTCA Special Committee 159: Global Positioning System (GPS) (United States)


    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning 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). DATES: The meeting...

  9. 77 FR 56254 - 89th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS) (United States)


    ... Federal Aviation Administration 89th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS... Notice of RTCA Special Committee 159, RTCA Special Committee 159, Global Positioning Systems (GPS... Special Committee 159, Global Positioning Systems (GPS). DATES: The meeting will be held October 5, 2012...

  10. 76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS) (United States)


    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of intent to cancel... Positioning System (GPS), and request for public comment. SUMMARY: This notice announces the FAA's intent to cancel TSO-C129a, Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS...

  11. 77 FR 12106 - 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS) (United States)


    ... Federal Aviation Administration 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS... RTCA Special Committee 159, Global Positioning System (GPS). SUMMARY: The FAA is issuing this notice to advise the public of the 88th meeting of RTCA Special Committee 159, Global Positioning System (GPS...

  12. 78 FR 13396 - 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS) (United States)


    ... Federal Aviation Administration 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS... Notice of RTCA Special Committee 159, RTCA Special Committee 159, Global Positioning Systems (GPS... Special Committee 159, Global Positioning Systems (GPS). DATES: The meeting will be held March 12-15, 2013...

  13. 75 FR 28318 - Eighty-Second Meeting: RTCA Special Committee 159: Global Positioning System (GPS) (United States)


    ... System (GPS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of RTCA Special Committee 159 meeting: Global Positioning 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). DATES: The meeting...

  14. Interdisciplinary cooperation of GPs in palliative care at home: a nationwide survey in The Netherlands

    NARCIS (Netherlands)

    Borgsteede, Sander D.; Deliens, Luc; van der Wal, Gerrit; Francke, Anneke L.; Stalman, Wim A. B.; van Eijk, Jacques T. M.


    OBJECTIVE: To investigate the occurrence and predictors of interdisciplinary cooperation of GPs with other caregivers in palliative care at home. DESIGN: In a prospective study among 96 general practices, the GPs involved identified all dying patients during the study period of 12 months. The GPs

  15. 77 FR 25510 - GPS Funds I, et al.; Notice of Application (United States)


    ... From the Federal Register Online via the Government Publishing Office ] SECURITIES AND EXCHANGE COMMISSION GPS Funds I, et al.; Notice of Application April 24, 2012. AGENCY: Securities and Exchange... 12d1-2 under the Act to invest in certain financial instruments. Applicants: GPS Funds I, GPS Funds II...

  16. 75 FR 51481 - In the Matter of Certain GPS Devices and Products Containing Same; Modification Proceeding (United States)


    ... COMMISSION In the Matter of Certain GPS Devices and Products Containing Same; Modification Proceeding Notice... within the United States after importation of certain GPS (Global Positioning System) devices and... within the United States after importation of certain GPS devices and products containing the same. The...

  17. GPS radio collar 3D performance as influenced by forest structure and topography (United States)

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


    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...

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


    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...

  19. GPS/Galileo Interoperability: GGTO, Timing Biases, and Giove-A Experience (United States)


    GPS Time EGST EGGTO RX GD1 RXC USER RX ISB user clock RX ED1 GPS Time Klobuchar model NeQuick model Figure 11. User solution for a single...delay can be corrected by the user receiver software by using the broadcast parameters for the Klobuchar model (GPS) and the NeQuick model (Galileo

  20. Road Charging in Copenhagen: A Comparative Study of the GPS Performance

    DEFF Research Database (Denmark)

    Zabic, Martina


    The paper presents results from a comparative study on the GPS performance based on experiments carried out in Copenhagen, Denmark in both 2003 and 2008. GPS data from 40 vehicles were collected to re-evaluate the GPS performance in a Danish environment and thereby assess the level of performance...

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

    Directory of Open Access Journals (Sweden)

    Felicity Goodyear-Smith


    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.

  2. On the reduction and analysis for GPS common view data (United States)

    Wang, Z. M.


    It is necessary for an atomic time scale consisting of many atomic clocks distributed at remote time labs to have a time link network. Though a few baselines of the Two Way Satellite Time Transfer have been introduced into TAI computation, GPS Common View (GPS CV) will still be the main means for TAI as well as other time scales such as the Joint Atomic Time of China (JATC). The reduction and analysis on the data of GPS CV are important for improving the precision and accuracy of the time links. The GPS CV data of CRL-CSAO for about 18 months as well as those with different lengths of baselines in the world have been analyzed. The errors in the adopted coordinates of the antenna (?Ucoor) were the main source of errors for CSAO before the end of May 2000. The noisy receiver at CSAO causes a larger RMS in the data of CRL-CSAO than those for CRL-NAO and CRL-KRIS. The way for calculating the statistical corrections is described and the methods for obtaining the corrections for the systematic errors caused by the inaccuracy of the satellite ephemeris (?UE) and the ionosphere model (?UION) are explained. It is expectable that the uncertainty of the GPS CV could reach 2~3 ns for both short and long baselines if the main systematic errors ?Ucoor???UE and ?UION can be removed and the low noise receiver with temperature stabilized antenna as well as the choke ring for anti-multi-path interference can be used.

  3. Monitoring accelerations with GPS in football: time to slow down? (United States)

    Buchheit, Martin; Al Haddad, Hani; Simpson, Ben M; Palazzi, Dino; Bourdon, Pitre C; Di Salvo, Valter; Mendez-Villanueva, Alberto


    The aims of the current study were to examine the magnitude of between-GPS-models differences in commonly reported running-based measures in football, examine between-units variability, and assess the effect of software updates on these measures. Fifty identical-brand GPS units (15 SPI-proX and 35 SPIproX2, 15 Hz, GPSports, Canberra, Australia) were attached to a custom-made plastic sled towed by a player performing simulated match running activities. GPS data collected during training sessions over 4 wk from 4 professional football players (N = 53 files) were also analyzed before and after 2 manufacturer-supplied software updates. There were substantial differences between the different models (eg, standardized difference for the number of acceleration >4 m/s2 = 2.1; 90% confidence limits [1.4, 2.7], with 100% chance of a true difference). Between-units variations ranged from 1% (maximal speed) to 56% (number of deceleration >4 m/s2). Some GPS units measured 2-6 times more acceleration/deceleration occurrences than others. Software updates did not substantially affect the distance covered at different speeds or peak speed reached, but 1 of the updates led to large and small decreases in the occurrence of accelerations (-1.24; -1.32, -1.15) and decelerations (-0.45; -0.48, -0.41), respectively. Practitioners are advised to apply care when comparing data collected with different models or units or when updating their software. The metrics of accelerations and decelerations show the most variability in GPS monitoring and must be interpreted cautiously.

  4. Survey and research on precision polymerization polymeric materials; Seimitsu jugo kobunshi zairyo ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)



    Survey and research on the precision control of primary structure of polymeric materials and the precision evaluation technology have been conducted to develop advanced polymeric materials. It is proposed that the three basic processes of polymer synthesis, i.e., addition, condensation, and biomimesis, in forming the precision polymerization skeleton are to be covered through a centralized joint research effort with participation of industry, academia, and the government institute and under the leadership of researchers from academic institutions as the team leaders. For the study of technology trends, international conferences held in UK, Germany, and Hawaii are introduced, and domestic meetings, i.e., Annual Polymer Congress and Polymer Conference, are summarized. In addition, Precision Polymerization Forum and International Workshop on Precision Polymerization were held. The basic studies include a quantum-chemical elucidation of the elementary process in polymerization reaction, time-resolved analysis of polymerization process and polymer properties, synthesis of polymers with controlled microstructures by coordination polymerization using metal complexes, synthesis of polymer with controlled microstructures by precision polycondensation, molecular recognition in catalyst-reaction site, and synthesis of imprinting polymers. 246 refs., 117 figs., 14 tabs.

  5. Development of precision casting in high speed steel; Seimitsu chuzo haisu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, H.; Fujii, T. [Daido Steel Co. Ltd., Nagoya (Japan)


    As to the high speed steel manufactured by precision casting process, effect of decarbonization technology and low temperature casting, and difference between the characteristics of a steel and a high speed steel were examined. The high speed steel was cast by vacuum casing process using a mold manufactured by the lost wax process. Effect of superheating in casting on the product structure and the bending strength was examined. Decarbonization can be prevented by the vacuum casting process. By low temperature casting, the high speed steel structure becomes fine, and the bending strength or toughness is improved; 80% of the T-direction bending strength of the steel can be secured in the high speed steel. The high speed steel exceeds the steel by a little bit in abrasion resistance. When the high speed steel was applied to a spiral cutter, the high speed steel product exceeded 1.2 times the machined steel in the tool life. In the high speed steel, the cutting process is drastically reduced, and reduction of the material cost is also possible compared with the machined steel. The high speed steel is considered to show good results because of excellent abrasion resistance since the tool life depended more on abrasion than on toughness because of the machining conditions. 4 refs., 8 figs., 2 tabs.

  6. Wireless inertial measurement unit with GPS (WIMU-GPS)--wearable monitoring platform for ecological assessment of lifespace and mobility in aging and disease. (United States)

    Boissy, Patrick; Brière, Simon; Hamel, Mathieu; Jog, Mandar; Speechley, Mark; Karelis, Antony; Frank, James; Vincent, Claude; Edwards, Rodrick; Duval, Christian


    This paper proposes an innovative ambulatory mobility and activity monitoring approach based on a wearable datalogging platform that combines inertial sensing with GPS tracking to assess the lifespace and mobility profile of individuals in their home and community environments. The components, I/O architecture, sensors and functions of the WIMU-GPS are presented. Outcome variables that can be measured with it are described and illustrated. Data on the power usage, operating autonomy of the WIMU-GPS and the GPS tracking performances and time to first fix of the unit are presented. The study of lifespace and mobility with the WIMU-GPS can potentially provide unique insights into intrapersonal and environmental factors contributing to mobility restriction. On-going studies are underway to establish the validity and reliability of the WIMU-GPS in characterizing the lifespace and mobility profile of older adults.

  7. Airborne Antenna System for Minimum-Cycle-Slip GPS Reception (United States)

    Wright, C. Wayne


    A system that includes a Global Positioning System (GPS) antenna and associated apparatus for keeping the antenna aimed upward has been developed for use aboard a remote-sensing-survey airplane. The purpose served by the system is to enable minimum- cycle-slip reception of GPS signals used in precise computation of the trajectory of the airplane, without having to restrict the airplane to maneuvers that increase the flight time needed to perform a survey. Cycle slip signifies loss of continuous track of the phase of a signal. Minimum-cycle-slip reception is desirable because maintaining constant track of the phase of the carrier signal from each available GPS satellite is necessary for surveying to centimeter or subcentimeter precision. Even a loss of signal for as short a time as a nanosecond can cause cycle slip. Cycle slips degrade the quality and precision of survey data acquired during a flight. The two principal causes of cycle slip are weakness of signals and multipath propagation. Heretofore, it has been standard practice to mount a GPS antenna rigidly on top of an airplane, and the radiation pattern of the antenna is typically hemispherical, so that all GPS satellites above the horizon are viewed by the antenna during level flight. When the airplane must be banked for a turn or other maneuver, the reception hemisphere becomes correspondingly tilted; hence, the antenna no longer views satellites that may still be above the Earth horizon but are now below the equatorial plane of the tilted reception hemisphere. Moreover, part of the reception hemisphere (typically, on the inside of a turn) becomes pointed toward ground, with a consequent increase in received noise and, therefore, degradation of GPS measurements. To minimize the likelihood of loss of signal and cycle slip, bank angles of remote-sensing survey airplanes have generally been limited to 10 or less, resulting in skidding or slipping uncoordinated turns. An airplane must be banked in order to make

  8. Mapping Multi-Day GPS Data: A Cartographic Study in NYC. (United States)

    Duncan, Dustin T; Regan, Seann D

    Multi-day GPS data is increasingly being used in research-including in the field of spatial epidemiology. We present several maps as ways to present multi-day GPS data. Data come from the NYC Low-Income Housing, Neighborhoods and Health Study (n=120). Participants wore a QStarz BT-Q1000XT GPS device for about a week (mean: 7.44, SD= 2.15). Our maps show various ways to visualize multi-day GPS data; these data are presented by overall GPS data, by weekday/weekend and by day of the week. We discuss implications for each of the maps.

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


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


    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...

  10. Noise in GPS position time series from Taiwan (United States)

    Rau, Ruey-Juin; Hung, Huang-Kai


    Position time series of 393 continuous GPS (CGPS) stations with durations of 5-10 years are generated and analyzed for the noise model and seasonal motions in Taiwan. The noise parameters obtained are also used to evaluate the reliability of GPS velocity uncertainties. GPS data are processed by GAMIT/GLOBK to obtain the position time series. To obtain the seasonal properties in the CGPS time series, we modeled each GPS position time series to derive the secular velocity, seasonal variations in annual and semi-annual periods, offsets due to the antenna changing and co-seismic deformations using the weighted least square method. Uncertainties of the residual position time series after removing the modeling motions for each CGPS station are evaluated by the weighted root mean square (WRMS). The average WRMS of position time series for all CGPS stations are 1.8-2.5 mm and 3.9-7.7 mm in the horizontal and vertical components, respectively. GPS daily position time series are considered to be the signal pattern of the white plus flicker noise. The overall seasonal amplitudes for all the GPS stations are 1.8-3.3 mm in horizontal and 3.2-8.8 mm in the vertical component. Areas of strongest annual amplitudes in both horizontal and vertical components are concentrated in the west and southwest coastal plain in Taiwan which suffers severe ground subsidence from water over-pumping. The motions shown here appear to be elastic and are most likely induced by the effective stress in the regional aquifer changing between expansion and contraction. Stations located just east of the Longitudinal Valley in eastern Taiwan show high correlation between the horizontal seasonal motions and rainfall and groundwater levels. This may be resulted from the periodic contraction and extension motions of the Longitudinal Valley fault due to variations in hydrological loadings. Uncertainty of CGPS velocities estimated by the noise patterns of the Power Law noise series indicated that the

  11. Application of GPS Measurements for Ionospheric and Tropospheric Modelling (United States)

    Rajendra Prasad, P.; Abdu, M. A.; Furlan, Benedito. M. P.; Koiti Kuga, Hélio

    military navigation. The DOD's primary purposes were to use the system in precision weapon delivery and providing a capability that would help reverse the proliferation of navigation systems in military. Subsequently, it was very quickly realized that civil use and scientific utility would far outstrip military use. A variety of scientific applications are uniquely suited to precise positioning capabilities. The relatively high precision, low cost, mobility and convenience of GPS receivers make positioning attractive. The other applications being precise time measurement, surveying and geodesy purposes apart from orbit and attitude determination along with many user services. The system operates by transmitting radio waves from satellites to receivers on the ground, aircraft, or other satellites. These signals are used to calculate location very accurately. Standard Positioning Services (SPS) which restricts access to Coarse/Access (C/A) code and carrier signals on the L1 frequency only. The accuracy thus provided by SPS fall short of most of the accuracy requirements of users. The upper atmosphere is ionized by the ultra violet radiation from the sun. The significant errors in positioning can result when the signals are refracted and slowed by ionospheric conditions, the parameter of the ionosphere that produces most effects on GPS signals is the total number of electrons in the ionospheric propagation path. This integrated number of electrons, called Total Electron Content (TEC) varies, not only from day to night, time of the year and solar flux cycle, but also with geomagnetic latitude and longitude. Being plasma the ionosphere affects the radio waves propagating through it. Effects of scintillation on GPS satellite navigation systems operating at L1 (1.5754 GHz), L2 (1.2276 GHz) frequencies have not been estimated accurately. It is generally recognized that GPS navigation systems are vulnerable in the polar and especially in the equatorial region during the

  12. Transport on prescription: How can GPs contribute to the promotion of active transport? (United States)

    Pistoll, Chance; Furler, John


    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.

  13. To make a difference – how GPs conceive consultation outcomes. A phenomenographic study

    Directory of Open Access Journals (Sweden)

    Andersson Sven-Olof


    Full Text Available Abstract Background Outcomes from GPs' consultations have been measured mainly with disease specific measures and with patient questionnaires about health, satisfaction, enablement and quality. The aim of this study was to explore GPs' conceptions of consultation outcomes. Methods Interviews with 17 GPs in groups and individually about consultation outcomes from recently performed consultations were analysed with a phenomenographic research approach. Results The GPs conceived outcomes in four ways: patient outcomes, GPs' self-evaluation, relationship building and change of surgery routines. Conclusion Patient outcomes, as conceived by the GPs, were generally congruent with those that had been taken up in outcome studies. Relationship building and change of surgery routines were outcomes in preparation for consultations to come. GPs made self-assessments related to internalized norms, grounded on a perceived collegial professional consensus. Considerations of such different aspects of outcomes can inspire professional development.

  14. [Contract Conditions for GPs in Training while Working in Ambulatory Care]. (United States)

    Herrmann, W J; Thiel, P; Weinert, K


    In Germany, the situation of GPs in training has received growing attention. Central funding of GPs in training who are working in ambulatory care has been increased up to 3 500 Euros/month. However, the contract conditions of GPs in training who are working in ambulatory care have been unknown as yet. An online survey was undertaken. We recruited GPs in training by snowball sampling making use of national and local organisations of GPs and GPs in training. Our questionnaire consisted of questions concerning sociodemographic variables, gross wage, working hours, holidays and free days for educational purposes. Data were analysed by descriptive statistical methods. 152 participants fulfilled the inclusion criteria. 127 were full time GPs in training. The median of gross wage was 3 500 Euros/month, the mean gross wage was 3 878 Euros/month. The gross wage per hour was lower than that for GPs in training who are working in hospitals. Especially part time GPs in training had a lower gross wage per hour. One third of the GPs in training had no free days for educational purposes. More than half of the GPs in training had a weekly meeting with their supervisor, however, more than one third of GPs in training had no or only irregular meetings with their supervisor. In Germany, GPs in training earn in ambulatory care less than in hospital care. They do not have sufficient free days for educational purposes and often there is a lack of supervision. This seems to indicate that GPs in training are mainly considered as cheap coworkers instead of trainees. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Algorithm for Detecting Significant Locations from Raw GPS Data (United States)

    Kami, Nobuharu; Enomoto, Nobuyuki; Baba, Teruyuki; Yoshikawa, Takashi

    We present a fast algorithm for probabilistically extracting significant locations from raw GPS data based on data point density. Extracting significant locations from raw GPS data is the first essential step of algorithms designed for location-aware applications. Assuming that a location is significant if users spend a certain time around that area, most current algorithms compare spatial/temporal variables, such as stay duration and a roaming diameter, with given fixed thresholds to extract significant locations. However, the appropriate threshold values are not clearly known in priori and algorithms with fixed thresholds are inherently error-prone, especially under high noise levels. Moreover, for N data points, they are generally O(N 2) algorithms since distance computation is required. We developed a fast algorithm for selective data point sampling around significant locations based on density information by constructing random histograms using locality sensitive hashing. Evaluations show competitive performance in detecting significant locations even under high noise levels.

  16. Group delay variations of GPS transmitting and receiving antennas (United States)

    Wanninger, Lambert; Sumaya, Hael; Beer, Susanne


    GPS code pseudorange measurements exhibit group delay variations at the transmitting and the receiving antenna. We calibrated C1 and P2 delay variations with respect to dual-frequency carrier phase observations and obtained nadir-dependent corrections for 32 satellites of the GPS constellation in early 2015 as well as elevation-dependent corrections for 13 receiving antenna models. The combined delay variations reach up to 1.0 m (3.3 ns) in the ionosphere-free linear combination for specific pairs of satellite and receiving antennas. Applying these corrections to the code measurements improves code/carrier single-frequency precise point positioning, ambiguity fixing based on the Melbourne-Wübbena linear combination, and determination of ionospheric total electron content. It also affects fractional cycle biases and differential code biases.

  17. Relativity, GPS, and the Validity of Common View Synchronization

    CERN Document Server

    Michelsen, Eric L


    We show here that Common View Synchronization is valid to synchronize distant clocks. We describe the relativistic physics, noting that a prerequisite for synchronization is the existence of a space-time with a stationary metric. The analysis shows that there are no Special Relativistic effects that need be included in the synchronization method, beyond those in a standard GPS clock. In particular, synchronizing a ground clock to the GPS satellite does not make that clock keep time in the reference frame of the satellite. Symmetries are very helpful in analyzing the behavior. We briefly describe some practical considerations in synchronizing distant earth clocks, such as antenna cabling and variations in receiver electronics, and how Common View Synchronization accommodates them.

  18. GPS IIF yaw attitude control during eclipse season (United States)

    Dilssner, F.; Springer, T.; Enderle, W.


    On May 27, 2010, the first satellite of the Block II "follow-on" (Block IIF) series, the fourth generation of Global Positioning System (GPS) spacecraft, has been successfully placed into orbit. GPS IIF-1, also referred to as space vehicle number (SVN) 62, has been injected into orbital plane B, slot position 2 of the GPS constellation. After completing three months of comprehensive in-orbit testing, the satellite entered service for the US Air Force (USAF) on August 26, 2010. A little over a year after the inaugural launch of GPS IIF-1, the USAF has now launched the second spacecraft of the IIF series (SVN-63). The IIF series includes a total of 12 satellites: SVN-62 through SVN-73. Despite having many technical advances over their predecessors such as enhanced rubidium frequency standards, more precise and powerful signals and an extended design life, the three-axis stabilized Block IIF satellites follow a completely different yaw attitude scheme, when passing through the Earth's shadow, to the Block IIA and IIR spacecraft. We will describe how high-rate carrier phase and pseudo-range measurements from a global GPS tracking network can be exploited to precisely monitor the yaw attitude behavior of SVN-62 and SVN-63 during their solar eclipse phases. The insights gained from this study have led to the development of a new GPS Block IIF yaw attitude model. We will show that the yaw rate of a Block IIF space vehicle is kept constant to the value needed to get the satellite back to near its nominal attitude when leaving the Earth's shadow and that a IIF satellite being in deep eclipse therefore needs to yaw significantly faster than an eclipsing IIF space vehicle passing only partly through the Earth's shadow. How the satellites' attitude control system (ACS) exactly computes this dynamical yaw rate parameter will be discussed here as well. Moreover, we will report on yaw attitude anomalies occurring when the GPS Block IIF satellites are shaded from the Sun by the

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

    DEFF Research Database (Denmark)

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


    , 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......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...... synchronized operation and even power sharing without any communication link. However, that method produces unwanted frequency fluctuations, which degrade the power quality. In order to improve the power quality of islanded MGs, a novel decentralized control method is proposed in this paper. In this method...

  20. Central and South America GPS geodesy - CASA Uno (United States)

    Kellogg, James N.; Dixon, Timothy H.


    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.

  1. The Parsec-Scale Morphology of Southern GPS Sources (United States)

    Edwards, P. G.; Tingay, S. J.


    Multi-frequency, multi-epoch ATCA observations of a sample of AGN resulted in the identification of nine new candidate Giga-hertz Peaked Spectrum sources. Here, we present Long Baseline Array observations at 4.8 GHz of the four candidates with no previously published VLBI image, and consider these together with previously published VLBI images of the other five sources. We find core-jet or compact double morphologies dominate, with further observations required to distinguish between these two possibilities for some sources. One of the nine candidates, PKS 1831-711, displays appreciable variability, suggesting its GPS spectrum is more ephemeral in nature. We focus in particular on the apparent relationship between a narrow spectral width and `compact double' parsec-scale morphology, finding further examples, but also exceptions to this trend. An examination of the VLBI morphologies high-redshift (z > 3) sub-class of GPS sources suggests that core-jet morphologies predominate in this class.

  2. Uav Onboard Photogrammetry and GPS Positionning for Earthworks (United States)

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


    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.

  3. Smartphone-based integrated PDR/GPS/Bluetooth pedestrian location (United States)

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


    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.

  4. Developing Digital Privacy: Children's Moral Judgments Concerning Mobile GPS Devices. (United States)

    Gelman, Susan A; Martinez, Megan; Davidson, Natalie S; Noles, Nicholaus S


    New technology poses new moral problems for children to consider. We examined whether children deem object tracking with a mobile GPS device to be a property right. In three experiments, 329 children (4-10 years) and adults were asked whether it is acceptable to track the location of either one's own or another person's possessions using a mobile GPS device. Young children, like adults, viewed object tracking as relatively more acceptable for owners than nonowners. However, whereas adults expressed negative evaluations of someone tracking another person's possessions, young children expressed positive evaluations of this behavior. These divergent moral judgments of digital tracking at different ages have profound implications for how concepts of digital privacy develop and for the digital security of children. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

  5. A transportation security system applying RFID and GPS

    Directory of Open Access Journals (Sweden)

    Ruijian Zhang


    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. 

  6. GPs' negotiation strategies regarding sick leave for subjective health complaints. (United States)

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


    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.

  7. Non-traditional approaches to teaching GPS online (United States)

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


    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.

  8. A New Trajectory Similarity Measure for GPS Data

    KAUST Repository

    Ismail, Anas


    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.

  9. Nonlinear Filtering for Hybrid GPS/GSM Mobile Terminal Tracking

    Directory of Open Access Journals (Sweden)

    Carsten Fritsche


    timing advance and received signal strengths from GSM. The three filters are compared with each other in terms of performance and computational complexity. Posterior Cramér-Rao lower bounds are evaluated in order to assess the theoretical performance. Furthermore, it is investigated how additional GPS reference time information available from GSM influences the performance of the hybrid localization method. Simulation and experimental results show that the proposed hybrid method outperforms the GSM method.

  10. Relationships Between Seismicity and GPS Determined Velocities in Northeast Asia (United States)

    Fujita, K.; Sella, G.; Mackey, K. G.; Stein, S.; Park, K.; Imaev, V. S.


    Published GPS data are equivocal about the existence of the Okhotsk and Amur plates in northeast Asia. Seismicity data, however, clearly delineate these plates, as well as possible additional blocks. The northern boundary of the Okhotsk plate is separated from both North America and Eurasia by diffuse zones of seismicity in northeast Russia. Seismicity in the Magadan region coincides with faults clearly visible in satellite imagery that are left-lateral based on offset rivers and focal mechanisms. The largest earthquakes (~M 5) are associated with specific faults. Although GPS velocities are generally consistent with the motion of North America, their residual velocity (with respect to North America) shows a gradient across this zone of seismicity with relative displacements increasing towards the Okhotsk plate. The eastern boundary of the Amur plate is generally accepted as lying along Sakhalin Island and bordering the Okhotsk plate. However, several bands of north-south seismicity exist west of this boundary along possible extensions of the Tanlu fault of northeastern China. This seismicity extends the Tanlu to intersect with an east-west striking zone of seismicity separating Amur and Eurasia which connects Lake Baikal and Sakhalin. This seismic extension of the Tanlu implies that a small block may exist between Okhotsk and Amur that extends south to include Korea. Although the events are small, the linear and arcuate trends in seismicity clearly imply active motion along specific faults. However, there is no clear signature of active faulting in the geomorphology or geology. GPS sites in eastern Amur are too close to active to constrain block motions, however, additional blocks may be needed in interpreting GPS results from Amur, Sakhalin, Korea, and northeast China, especially given the low velocities with respect to Eurasia.

  11. Expected Position Error for an Onboard Satellite GPS Receiver (United States)


    Technology Air University Air Education and Training Command in Partial Fulfillment of the Requirements for the Degree of Master of Science in...on-board a satellite as part of a bigger experiment. The “Navigation and Occultation eXperiment” uses a GPS receiver on a small satellite “TET-1” to...determination and surveying the environment through radio occultation [12]. 15 2.8 Tools Used in Research A combination of three different tools are

  12. GPS Receiver and Satellite DCB Estimation using Ionospheric TEC


    Byung-Kyu Choi; Sung-Ki Cho; Sang-Jeong Lee


    We estimated the receiver and satellite differential code bias (DCB) based on the ionospheric total electron content (TEC) estimation method. The GPS network which has been operated by the Korea Astronomy and Space Science Institute (KASI) was designed to calculate TEC. The receiver and satellite DCB values were obtained from the weighted least square method with time interval for one hour. The results represented that the receiver DCB values are mostly varying within ±2 meter and are derived...

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

    Directory of Open Access Journals (Sweden)

    Prospero De Martino


    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.

  14. Inversion of Ionospheric Electron Density from GPS Beacon Observations

    Institute of Scientific and Technical Information of China (English)

    Zou Yu-hua; Xu Ji-sheng


    This paper studies the mathematical foundation of time-dependent three-dimensional (3-D) computerized ionospheric tomography (CIT) for reconstructing ionospheric electron density, Ne, from ground-based GPS beacon observations. After simplifying the relation between Ne and time,the time-dependent 3-D inversion in consideration is reduced to a 3-D tomography with incomplete projections.To see clearly the effects of the incompleteness on the quality of reconstruction under 3-D condition, the formula of 3-D parallel-beam tomography is deduced theoretically. After establishing the mathematical foundation, simulations based on actual GPS ray paths with the help of the IRI-90 model are performed,and reasonable time-dependent 3-D distribution images of Neare obtained when taking proper layout of the network and allowing variable resolutions. The quality of the reconstruction is rather good when compared with the images from the IRI-90 model directly. Therefore, results in this paper demon-strate that imaging of the ionospheric electron density distri-bution from GPS beacon observations is reasonable in theory and feasible in practice.

  15. Inversion of Ionospheric Electron Density from GPS Beacon Observations

    Institute of Scientific and Technical Information of China (English)

    ZouYu-hua; XuJi-sheng


    This paper studies the mathematical foundation of time-dependent three-dimensional (3-D) computerized ionospheric tomography (CIT) for reconstructing ionospheric electron density, N~, from ground-based GPS beacon observations. After simplifying the relation between N. and time,the time-dependent 3-D inversion in consideration is reduced to a 3-D tomography with incomplete projections. To see clearly the effects of the incompleteness on the quality of reconstruction under 3-D condition, the formula of 3-D parallelbeam tomogtTaphy is deduced theoretically. After establishing the mathematical foundation, simulations based on actual GPS ray paths with the help of the IRI-90 model are performed,and reasonable time-dependent 3-D distribution images of Ne are obtained when taking proper layout of the network and allowing variable resolutions. The quality of the reconstruction is rather good when compared with the images from the IRI-90 model directly. Therefore, results in this paper demonstrate that imaging of the ionospheric electron density distribution from GPS beacon observations is reasonable in theor yand feasible in practice.

  16. Anomalous crustal movements before great Wenchuan earthquake observed by GPS

    Directory of Open Access Journals (Sweden)

    Gu Guohua


    Full Text Available Studies of GPS data carried out before and after the great Wenchuan earthquake of Ms8.0 on May 12, 2008 show that anomalous crustal movements occurred before the earthquake. Data from 4 pre-earthquake observation sessions at a dense network of stations show that there were prominent broad-ranged long- and mid-term anomalies in horizontal displacements and strain and in vertical displacements. Data from the fewer-numbered reference stations of continuous GPS observations since 1999 in West and South China showed short-term preseismic anomalies in horizontal displacements. The detection of co-seismic horizontal displacements at these stations supports the existence of the pre-earthquake anomalies. Results of single-epoch solutions of data from continuous-observation stations near the epicenter also show large imminent anomalies in vertical displacements. Although the Wenchuan earthquake was not predicted, these results give a strong indication that GPS should be the main observation technique for long-term, mid-term, short-term and imminent earthquake predictions.

  17. GPS sledovací systém


    Hofman, Jan


    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...

  18. Cycling/Running Training Diary Using GPS Data


    Matera, Tomáš


    Cílem praktické části práce je vytvořit aplikaci s vhodným grafickým uživatelským rozhraním, která bude umožňovat import tréninkových dat z GPS zařízení. Dále bude vytvářet grafické a statistické výstupy dosažených výsledků s možností jejich exportu do HTML a formátu podporovaného tabulkovými procesory. Teoretická část práce se týká úvodu do vedení a zaznamenávání tréninku, krátkého popisu funkce GPS systému, popisu formátu pro ukládání získaných GPS dat a návrhu aplikace. This master's th...

  19. Towards Observing Tsunamis in the Ionosphere Using GPS TEC Measurements (United States)

    Galvan, D. A.; Komjathy, A.; Mannucci, A.; Hickey, M. P.; Schubert, G.; Walterscheid, R. L.; Occhipinti, G.


    Recent modeling results and observations have demonstrated that the ionospheric signature of an ocean tsunami can potentially be detected as a traveling ionospheric disturbance (TID) produced by internal gravity waves propagating upward in the atmosphere [e.g., Hickey et al., (2009), Occhipinti et al., (2006)]. These tsunamigenic TID’s have been demonstrated to be present in total electron content (TEC) measurements using ground-based GPS radio signals [e.g., Artru et al., (2005)] and satellite-based altimeter radar [Occhipinti et al., (2006)]. There are many remaining unanswered questions regarding the reliability of detecting tsunamigenic TIDs, including how to distinguish them from TIDs of non-tsunamigenic origin, as well as factors affecting the propagation of internal gravity waves in the ionosphere. We present ongoing research analyzing ground-based GPS TEC observations during multiple known tsunami events. Specifically, fluctuations in TEC are obtained by comparing observed TEC with modeled TEC estimates using JPL’s Global Ionospheric Mapping (GIM) system. These small fluctuations are then band-passed filtered and Fourier analyzed, across multiple GPS satellites and ground stations, to search for wave patterns similar to the coincident ocean tsunami in the same geographic region. Results are discussed in terms of the degree to which a tsunamigenic TID is observed in each case, and the possible causes for failing to observe them. Comparisons between observations and results from theoretical models of tsunamigenic ionospheric wave propagation are also discussed for specific cases.

  20. Effect of reference stations on continuous GPS (CGPS) time series (United States)

    Sella, G. F.; Malservisi, R.; Wdowinski, S.; Dixon, T.; Lafemina, P.


    Time series of CGPS sites in the ITRF2000 reference frame show a significant "bump" in late 2002. The time series suggest that the position of the GPS monument has moved significantly compared to the expected steady velocity prediction. Although the change has only a slight effect on computed velocities for long time series, it may introduce a significant bias in the computed velocity for shorter time series and in time series only using data collected during episodic GPS campaigns. The "bump" is easily recognized in North American sites but can also be observed in sites around the world, indicating a global effect. It is also present in time series produced by different analysis groups with different software packages (GIPSY-OASIS, GAMIT). We propose that the bump is related to "misbehavior" of one or more references sites used to transform raw GPS positions into ITRF2000. The "bump" appears to coincide with discontinuity in the operation of some reference stations. We also find that daily positions estimates are particularly sensitive to the behavior of some reference stations.

  1. GPS Data Filtration Method for Drive Cycle Analysis Applications

    Energy Technology Data Exchange (ETDEWEB)

    Duran, A.; Earleywine, M.


    When employing GPS data acquisition systems to capture vehicle drive-cycle information, a number of errors often appear in the raw data samples, such as sudden signal loss, extraneous or outlying data points, speed drifting, and signal white noise, all of which limit the quality of field data for use in downstream applications. Unaddressed, these errors significantly impact the reliability of source data and limit the effectiveness of traditional drive-cycle analysis approaches and vehicle simulation software. Without reliable speed and time information, the validity of derived metrics for drive cycles, such as acceleration, power, and distance, become questionable. This study explores some of the common sources of error present in raw onboard GPS data and presents a detailed filtering process designed to correct for these issues. Test data from both light and medium/heavy duty applications are examined to illustrate the effectiveness of the proposed filtration process across the range of vehicle vocations. Graphical comparisons of raw and filtered cycles are presented, and statistical analyses are performed to determine the effects of the proposed filtration process on raw data. Finally, an evaluation of the overall benefits of data filtration on raw GPS data and present potential areas for continued research is presented.

  2. Guidance simulation and test support for differential GPS flight experiment (United States)

    Geier, G. J.; Loomis, P. V. W.; Cabak, A.


    Three separate tasks which supported the test preparation, test operations, and post test analysis of the NASA Ames flight test evaluation of the differential Global Positioning System (GPS) are presented. Task 1 consisted of a navigation filter design, coding, and testing to optimally make use of GPS in a differential mode. The filter can be configured to accept inputs from external censors such as an accelerometer and a barometric or radar altimeter. The filter runs in real time onboard a NASA helicopter. It processes raw pseudo and delta range measurements from a single channel sequential GPS receiver. The Kalman filter software interfaces are described in detail, followed by a description of the filter algorithm, including the basic propagation and measurement update equations. The performance during flight tests is reviewed and discussed. Task 2 describes a refinement performed on the lateral and vertical steering algorithms developed on a previous contract. The refinements include modification of the internal logic to allow more diverse inflight initialization procedures, further data smoothing and compensation for system induced time delays. Task 3 describes the TAU Corp participation in the analysis of the real time Kalman navigation filter. The performance was compared to that of the Z-set filter in flight and to the laser tracker position data during post test analysis. This analysis allowed a more optimum selection of the parameters of the filter.

  3. Topical corticosteroid addiction and withdrawal - An overview for GPs. (United States)

    Sheary, Belinda


    Topical corticosteroid (TCS) withdrawal (addiction) is a potential complication of TCS treatment, particularly where there has been an inappropriate long-term use of moderate-to-potent TCS on the face or genital area. TCS addiction and withdrawal is increasingly being discussed in social and mainstream media; however, it has received little attention in medical publications. Australian general practitioners (GPs) may come into contact with patients who have read material or watched videos about this condition. The objective of this article is to provide a succinct, evidence-based overview of TCS addiction and withdrawal for GPs. TCSs are indicated in the management of many patients with eczema. By being aware of TCS addiction and withdrawal, practitioners may be better able to help prevent this adverse effect and offer supportive care to patients in TCS withdrawal. It would also be useful for GPs to be able to discuss TCS addiction and withdrawal with patients who seek to clarify information they glean from non-medical sources.

  4. Quantifying movement demands of AFL football using GPS tracking. (United States)

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


    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 pfootball were evident between 2005 and 2008. The increasing speed of the game has implications for game authorities, players and coaching staff.

  5. Performance evaluation of GPS receiver under equatorial scintillation

    Directory of Open Access Journals (Sweden)

    Alison de Oliveira Moraes


    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.

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

    Directory of Open Access Journals (Sweden)

    E Chavoshi


    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

  7. Leaks in gas mains - Location using GIS and GPS; Leckstellen in Gasrohrnetzen. Aufspueren mit Unterstuetzung durch GIS und GPS

    Energy Technology Data Exchange (ETDEWEB)

    Huber, D.


    This article takes a look how leaks in gas mains can be located with the help of geographical information systems (GIS) and the satellite-based Global Positioning System (GPS). The advantages for long-term planning and, in future, maintenance work are stressed. Experienced gained by the IWB utility in Basel, Switzerland, is discussed. Here, a system for the monitoring and maintenance of the whole of the City of Basel's natural gas supply network is discussed. Cost savings and a particularly improved increase in the quality of leak detection work is noted. Modern technology using GPS-based equipment in the detection of leaks in the gas mains is reviewed. An example of the documentation of the gas mains in a GIS system is given.

  8. GPS coordinate time series measurements in Ontario and Quebec, Canada (United States)

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


    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

  9. Next-Generation GPS Station for Hazards Mitigation (Invited) (United States)

    Bock, Y.


    Our objective is to better forecast, assess, and mitigate natural hazards, including earthquakes, tsunamis, and extreme storms and flooding through development and implementation of a modular technology for the next-generation in-situ geodetic station to support the flow of information from multiple stations to scientists, mission planners, decision makers, and first responders. The same technology developed under NASA funding can be applied to enhance monitoring of large engineering structures such as bridges, hospitals and other critical infrastructure. Meaningful warnings save lives when issued within 1-2 minutes for destructive earthquakes, several tens of minutes for tsunamis, and up to several hours for extreme storms and flooding, and can be provided by on-site fusion of multiple data types and generation of higher-order data products: GPS/GNSS and accelerometer measurements to estimate point displacements, and GPS/GNSS and meteorological measurements to estimate moisture variability in the free atmosphere. By operating semi-autonomously, each station can then provide low-latency, high-fidelity and compact data products within the constraints of narrow communications bandwidth that often accompanies natural disasters. We have developed a power-efficient, low-cost, plug-in Geodetic Module for fusion of data from in situ sensors including GPS, a strong-motion accelerometer module, and a meteorological sensor package, for deployment at existing continuous GPS stations in southern California; fifteen stations have already been upgraded. The low-cost modular design is scalable to the many existing continuous GPS stations worldwide. New on-the-fly data products are estimated with 1 mm precision and accuracy, including three-dimensional seismogeodetic displacements for earthquake, tsunami and structural monitoring and precipitable water for forecasting extreme weather events such as summer monsoons and atmospheric rivers experienced in California. Unlike more

  10. GPS Observations of Plasma Bubbles and Scintillations over Equatorial Africa (United States)

    Carrano, C. S.; Valladares, C. E.; Semala, G. K.; Bridgwood, C. T.; Adeniyi, J.; Amaeshi, L. L.; Damtie, B.; D'Ujanga Mutonyi, F.; Ndeda, J. D.; Baki, P.; Obrou, O. K.; Okere, B.; Tsidu, G. M.


    Sponsored in part by the International Heliophysical Year (IHY) program, Boston College, Air Force Research Laboratory (AFRL), and several universities in Africa have collaborated to deploy a network of GPS receivers throughout equatorial Africa, a region which has been largely devoid of ground-based ionospheric monitoring instruments. High date-rate GPS receivers capable of measuring Total Electron Content (TEC) and GPS scintillations were installed at Abidjan, Ivory Coast (5.3°N, 4.0°W, dip 3.5°S); Addis Ababa (9.0°N, 38.8°E, dip 0.1°N ); Bahir Dar, Ethiopia (26.1°N, 50.6°E, dip 20.1°N); Cape Verde (16.6°S, 22.9°W, dip 4.9°N); Ilorin, Nigeria (8.4°S, 4.7°E, dip 1.9°S); Kampala, Uganda (0.3°S, 32.6°E, dip 9.2°S); Lagos, Nigeria (6.5°N, 3.4°E, dip 3.1°S); Nairobi, Kenya (1.3°S, 36.8°W, dip 10.7°S); Nsukka, Nigeria (6.8°S, 7.4°W, dip 3.0°S); and Zanzibar, Tanzania (6.2°S, 39.2°E, dip 15.9°S). In this paper we report on the longitudinal, local time and seasonal occurrence of plasma bubbles and L band scintillations over equatorial Africa in 2009 and 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The plasma bubbles are detected using an automated technique, whereby the GPS TEC is detrended to remove the diurnal variation and excursions exceeding a particular threshold are extracted for further analysis. A harmonic analysis (FFT) of these extracted events is performed to exclude wavelike features indicative of gravity waves or traveling ionospheric disturbances, and the remaining events are identified as plasma bubbles. Our findings suggest that the occurrence of plasma bubbles and L band scintillations over Africa are well correlated, but that some discrepancies in their morphologies are evident. While plasma bubbles and scintillations are generally observed during equinoctial

  11. Apoyo a Estudios Geodinamicos con GPS en Guatemala (United States)

    Robles, V. R.


    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

  12. Plate Boundary Observatory GPS Network Status in California (United States)

    Walls, C. P.; Austin, K. E.; Dittman, T.; Mann, D.; Basset, A.; Turner, R.; Lawrence, S.; Woolace, A. C.; Kasmer, D.; Hodgkinson, K. M.; Feaux, K.; Mattioli, G. S.


    The EarthScope PBO GPS network, funded by the NSF and operated by UNAVCO, is comprised of 599 permanent GPS stations spanning three principal tectonic regimes and is administered by separate management regions (Subduction - Pacific Northwest [91 sites], Extension - East [41 sites], Transform - Southwest [467 sites]). Since the close of construction in September 2008 various enhancements have been implemented through additional funding by the NSF, NOAA, and NASA and in collaboration with stakeholders such as Caltrans, Scripps, and the USGS. Initially, the majority of stations used first generation IP based cellular modems and radios capable of ~10KB/s data rates. The bandwidth limitation was a challenge for regional high-rate data downloads for GPS-seismology and airborne LiDAR surveys, and real-time data flow. Today, only 13 of the original cell modems remain with 297 upgraded cell modems providing 3G/4G/LTE data communications with transfer rates ranging from 80-400 KB/s. Ongoing radio network expansion and upgrades continue to harden communications. 32 VSAT and one manual download site remain. In CA, the network capabilities for 1Hz and 5Hz downloads or real-time streaming are ~95%, ~80% and ~65%, respectively. During the past year, uptime ranged from 94-99% with data return for 15 s data exceeding 99%. Real-time (1 Hz) data from 204 sites are distributed in BINEX and RTCM 2.3/3.1 formats with an average latency of 0.5 s and completion of 86%. A variety of geophysical sensors are co-located with the GPS stations and include: 21 MEMS accelerometers, 31 strong motion and broadband seismometers, 9 borehole strainmeters and 1 long baseline strainmeter. Vaisala meteorological instruments are located at 60 sites of which 38 stream GPS/Met data. In an effort to modernize the network, Trimble NetRS receivers are gradually being replaced with GNSS-capable/enabled receivers and antennas. Today, 11 stations are GLONASS enabled and 84 are GNSS capable.

  13. Snow Depth with GPS: Case Study from Minnesota 2010-2011 (United States)

    Bilich, A. L.; Slater, A. G.; Larson, K. M.


    Although originally designed to enable accurate positioning and time transfer, the Global Positioning System (GPS) has also proved useful for remote sensing applications. In this study, GPS signals are used to measure snow depth via GPS interferometric reflectometry (GPS-IR). In GPS-IR, a GPS antenna receives the desired direct signal as well as an indirect signal which reflects off of the ground or snow surface. These two signals interfere, and the composite signal recorded by the GPS receiver can be post-processed to yield the distance between the antenna and the reflecting surface, that is, distance to the snow surface. We present the results of a new snow depth product for the state of Minnesota over the winter of 2010-2011. Although single-station examples of GPS snow depth measurements can be found in the literature, this is one of the first studies to compute GPS snow depth over a large regional-scale network. We chose Minnesota because the state Department of Transportation runs a network of continuously operating reference stations (CORS) with many desired characteristics: freely available data, good GPS station distribution with good proximity to COOP weather stations, GPS stations located adjacent to farm fields with few sky obstructions, and receiver models known to have sufficient data quality for GPS-IR. GPS-IR with CORS has many advantages over traditional snow depth measurements. First, because we leverage existing CORS, no new equipment installations are required and data are freely available via the Internet. Second, GPS-IR with CORS measures a large area, approximately 100 m2 around the station and 20 m2 per satellite. We present snow depth results for over 30 GPS stations distributed across the state. We compare the GPS-IR snow depth product to COOP observations and SNODAS modeled estimates. GPS-IR snow depth is one of the few independent data sources available for assessment of SNODAS. Ideally snow depth via GPS-IR will be available for

  14. GPs opinions and perceptions of chiropractic in Sweden and Norway: a descriptive survey (United States)


    Background In Sweden, chiropractic is not included in mainstream health care. In Norway chiropractic is a recognized health care profession. The aim of this study was to explore the perceptions of chiropractic among Swedish and Norwegian General Practitioners (GPs). Methods Eight hundred surveys in each country were distributed randomly by post to Swedish and Norwegian GPs offices. The survey contained two main sections: Experiences and opinions about chiropractic and referral patterns. The data were then described and compared between the countries. Results In Sweden the response rate was 44.8% and in Norway 45.3%. More than half of the Swedish GPs participating in this study stated that they had poor knowledge about chiropractic, while just a tenth of Norwegian GPs stated the same. Nearly all Norwegian GPs had some experience of chiropractic treatment whilst a fairly large number of the Swedish GPs said that they had no experience at all of chiropractic. It was twice as common for GPs in Norway to refer patients to a chiropractor as compared to Sweden. However, Swedish and Norwegian GPs agreed that chiropractors were competent to treat musculo-skeletal conditions with an adequate education to be part of mainstream medicine. Conclusions Swedish and Norwegian GPs agree that chiropractors are competent to treat musculoskeletal conditions. However, there are many differences in GPs perceptions of chiropractic between the two countries and the overall picture indicates that chiropractic is more accepted and recognised as a health care profession in Norway. PMID:24128386

  15. The Quasi-Biennial Vertical Oscillations at Global GPS Stations: Identification by Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Yuanjin Pan


    Full Text Available Modeling nonlinear vertical components of a GPS time series is critical to separating sources contributing to mass displacements. Improved vertical precision in GPS positioning at stations for velocity fields is key to resolving the mechanism of certain geophysical phenomena. In this paper, we use ensemble empirical mode decomposition (EEMD to analyze the daily GPS time series at 89 continuous GPS stations, spanning from 2002 to 2013. EEMD decomposes a GPS time series into different intrinsic mode functions (IMFs, which are used to identify different kinds of signals and secular terms. Our study suggests that the GPS records contain not only the well-known signals (such as semi-annual and annual signals but also the seldom-noted quasi-biennial oscillations (QBS. The quasi-biennial signals are explained by modeled loadings of atmosphere, non-tidal and hydrology that deform the surface around the GPS stations. In addition, the loadings derived from GRACE gravity changes are also consistent with the quasi-biennial deformations derived from the GPS observations. By removing the modeled components, the weighted root-mean-square (WRMS variation of the GPS time series is reduced by 7.1% to 42.3%, and especially, after removing the seasonal and QBO signals, the average improvement percentages for seasonal and QBO signals are 25.6% and 7.5%, respectively, suggesting that it is significant to consider the QBS signals in the GPS records to improve the observed vertical deformations.

  16. Identification of nutrition communication styles and strategies: a qualitative study among Dutch GPs. (United States)

    van Dillen, Sonja M E; Hiddink, Gerrit J; Koelen, Maria A; de Graaf, Cees; van Woerkum, Cees M J


    The objectives of this study were to identify nutrition communication styles of Dutch GPs, their strategies regarding nutrition communication and nutrition information seeking behaviours. Another aim is to provide a hypothetical model for nutrition communication style, including psycho-social and socio-demographic variables. Nine focus groups with 81 GPs were used to obtain GPs' perceptions of nutrition communication. Data were analysed with the computer software program NUD*IST. Five nutrition communication styles were identified, namely informational, reference, motivational, confrontational and holistic style. Referring to a dietician, providing advice according to Dietary Guidelines, and offering written education materials were mentioned as strategies regarding nutrition communication. GPs sought nutrition information in scientific studies, specialist literature, and postgraduate training courses. The informational style of nutrition communication was dominant among Dutch GPs. GPs hardly provided maintenance advice for nutrition behaviour. Many GPs referred patients to dieticians, who were viewed as colleagues. GPs tried to get basic information about nutrition by scanning the literature, but they were seldom actively involved in seeking specific nutrition information. Although GPs felt that patients expect expert nutrition information, they perceived their nutrition knowledge as restricted. We advise to raise self-efficacy of GPs regarding nutrition communication and to build good collaboration with dieticians.

  17. 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)


    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.

  18. PFISR GPS tracking mode for researching high-latitude ionospheric electron density gradients associated with GPS scintillation (United States)

    Loucks, D. C.; Palo, S. E.; Pilinski, M.; Crowley, G.; Azeem, S. I.; Hampton, D. L.


    Ionospheric behavior in the high-latitudes can significantly impact Ultra High Frequency (UHF) signals in the 300 MHz to 3 GHz band, resulting in degradation of Global Positioning System (GPS) position solutions and satellite communications interruptions. To address these operational concerns, a need arises to identify and understand the ionospheric structure that leads to disturbed conditions in the Arctic. Structures in the high-latitude ionosphere are known to change on the order of seconds or less, can be decameters to kilometers in scale, and elongate across magnetic field lines at auroral latitudes. Nominal operations at Poker Flat Incoherent Scatter Radar (PFISR) give temporal resolution on the order of minutes, and range resolution on the order of tens of kilometers, while specialized GPS receivers available for ionospheric sensing have a 100Hz observation sampling rate. One of these, ASTRA's Connected Autonomous Space Environment Sensor (CASES) is used for this study. We have developed a new GPS scintillation tracking mode for PFISR to address open scientific questions regarding temporal and spatial electron density gradients. The mode will be described, a number of experimental campaigns will be analyzed, and results and lessons learned will be presented.

  19. Performance Analysis of Several GPS/Galileo Precise Point Positioning Models. (United States)

    Afifi, Akram; El-Rabbany, Ahmed


    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.

  20. Rural GPs' attitudes toward participating in emergency medicine: a qualitative study. (United States)

    Hjortdahl, Magnus; Halvorsen, Peder; Risør, Mette Bech


    Health authorities want to increase general practitioner (GP) participation in emergency medicine, but the role of the GP in this context controversial. We explored GPs' attitudes toward emergency medicine and call outs. Thematic analysis of focus group interviews. Four rural casualty clinics in Norway. GPs with experience ranging from one to 32 years. The GPs felt that their role had changed from being the only provider of emergency care to being one of many. In particular, the emergency medical technician teams (EMT) have evolved and often manage well without a physician. Consequently, the GPs get less experience and feel more uncertain when encountering emergencies. Nevertheless, the GPs want to participate in call outs. They believed that their presence contributes to better patient care, and the community appreciates it. Taking part in call outs is seen as being vital to maintaining skills. The GPs had difficulties explaining how to decide whether to participate in call outs. Decisions were perceived as difficult due to insufficient information. The GPs assessed factors, such as distance from the patient and crowding at the casualty clinic, differently when discussing participation in call outs. Although their role may have changed, GPs argue that they still play a part in emergency medicine. The GPs claim that by participating in call outs, they maintain their skills and improve patient care, but further research is needed to help policy makers and clinicians decide when the presence of a GP really counts. Norwegian health authorities want to increase participation by general practitioners (GPs) in emergency medicine, but the role of the GP in this context is controversial. KEY POINTS The role of the GP has changed, but GPs argue that they still play an important role in emergency medicine. GPs believe that their presence on call outs improve patient care, but they find it defensible that patients are tended to by emergency medical technicians (EMTs) only

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

    Directory of Open Access Journals (Sweden)

    L. Zhao


    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.

  2. New approach for earthquake/tsunami monitoring using dense GPS networks. (United States)

    Li, Xingxing; Ge, Maorong; Zhang, Yong; Wang, Rongjiang; Xu, Peiliang; Wickert, Jens; Schuh, Harald


    In recent times increasing numbers of high-rate GPS stations have been installed around the world and set-up to provide data in real-time. These networks provide a great opportunity to quickly capture surface displacements, which makes them important as potential constituents of earthquake/tsunami monitoring and warning systems. The appropriate GPS real-time data analysis with sufficient accuracy for this purpose is a main focus of the current GPS research. In this paper we propose an augmented point positioning method for GPS based hazard monitoring, which can achieve fast or even instantaneous precise positioning without relying on data of a specific reference station. The proposed method overcomes the limitations of the currently mostly used GPS processing approaches of relative positioning and global precise point positioning. The advantages of the proposed approach are demonstrated by using GPS data, which was recorded during the 2011 Tohoku-Oki earthquake in Japan.

  3. Estimation of interfrequency receiver biases in Korean Peninsula using GPS measurements (United States)

    Choi, Byung Kyu; Cho, Jung-Ho

    Interfrequency bias of the GPS (Global Positioning System) receiver and satellite has an effect to estimate the ionosphere TEC (Total Electron Contents). For more precise estimates of GPS-TEC, satellite and receiver instrumental biases should be calculated from GPS observables. The method for estimation the local TEC has been used the geometry-free linear combination derived from dual-frequency GPS observations. We estimated the receiver biases (also known as differential code biases) of 50 GPS reference stations in Korean Peninsula for improving an accuracy of ionosphere TEC. In this study, we found out that the GPS receivers in local area have a very large instrumental bias over 10 nano-seconds and also presented that this effect is a significant error source in the local ionosphere model.

  4. Analysis of signal acquisition in GPS receiver software

    Directory of Open Access Journals (Sweden)

    Vlada S. Sokolović


    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

  5. Predicting metabolic rate during level and uphill outdoor walking using a low-cost GPS receiver. (United States)

    de Müllenheim, Pierre-Yves; Dumond, Rémy; Gernigon, Marie; Mahé, Guillaume; Lavenu, Audrey; Bickert, Sandrine; Prioux, Jacques; Noury-Desvaux, Bénédicte; Le Faucheur, Alexis


    The objective of this study was to assess the accuracy of using speed and grade data obtained from a low-cost global positioning system (GPS) receiver to estimate metabolic rate (MR) during level and uphill outdoor walking. Thirty young, healthy adults performed randomized outdoor walking for 6-min periods at 2.0, 3.5, and 5.0 km/h and on three different grades: 1) level walking, 2) uphill walking on a 3.7% mean grade, and 3) uphill walking on a 10.8% mean grade. The reference MR [metabolic equivalents (METs) and oxygen uptake (V̇o2)] values were obtained using a portable metabolic system. The speed and grade were obtained using a low-cost GPS receiver (1-Hz recording). The GPS grade (Δ altitude/distance walked) was calculated using both uncorrected GPS altitude data and GPS altitude data corrected with map projection software. The accuracy of predictions using reference speed and grade (actual[SPEED/GRADE]) data was high [R(2) = 0.85, root-mean-square error (RMSE) = 0.68 MET]. The accuracy decreased when GPS speed and uncorrected grade (GPS[UNCORRECTED]) data were used, although it remained substantial (R(2) = 0.66, RMSE = 1.00 MET). The accuracy was greatly improved when the GPS speed and corrected grade (GPS[CORRECTED]) data were used (R(2) = 0.82, RMSE = 0.79 MET). Published predictive equations for walking MR were also cross-validated using actual or GPS speed and grade data when appropriate. The prediction accuracy was very close when either actual[SPEED/GRADE] values or GPS[CORRECTED] values (for level and uphill combined) or GPS speed values (for level walking only) were used. These results offer promising research and clinical applications related to the assessment of energy expenditure during free-living walking. Copyright © 2016 the American Physiological Society.

  6. Signal-to-Noise Ratio Prediction and Validation for Space Shuttle GPS Flight Experiment (United States)

    Hwu, Shian U.; Adkins, Antha A.; Loh, Yin-Chung; Brown, Lisa C.; Sham, Catherine C.; Kroll, Quin D.


    A deterministic method for Space Station Global Positioning System (GPS) Signal-To- Noise Ratio (SNR) predictions is proposed. The complex electromagnetic interactions between GPS antennas and surrounding Space Station structures are taken into account by computational electromagnetic technique. This computer simulator is capable of taking into account multipath effects from dynamically changed solar panels and thermal radiators. A comparison with recent collected Space Station GPS system flight experiment data is presented. The simulation results are in close agreement with flight data.

  7. Improvement and Refinement of the GPS/MET Data Analysis Algorithm (United States)

    Herman, Benjamin M.


    The GPS/MET project was a satellite-to-satellite active microwave atmospheric limb sounder using the Global Positioning System transmitters as signal sources. Despite its remarkable success, GPS/MET could not independently sense atmospheric water vapor and ozone. Additionally the GPS/MET data retrieval algorithm needs to be further improved and refined to enhance the retrieval accuracies in the lower tropospheric region and the upper stratospheric region. The objectives of this proposal were to address these 3 problem areas.

  8. GPs' attitudes, beliefs and behaviours regarding exercise for chronic knee pain: a questionnaire survey. (United States)

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


    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.

  9. Multiple inflation events at Akutan volcano, Alaska, from GPS observations (United States)

    Hyeun Ji, Kang; Rim, Hyoung-Rae


    Detecting anomalous volcanic activities helps constrain characteristics of eruption cycles. We have developed a signal detection tool, called Targeted Projection Operator (TPO), to monitor surface deformation with Global Positioning System (GPS) data. We assume that deformation events of a volcano have similar spatial patterns but with different amplitudes. This assumption is reasonable because a deformation source (e.g., a magma chamber) is relatively stationary in space but its strength varies in time. TPO projects GPS position time series onto a pre-determined spatial pattern (or "target") and calculates the amplitude of the projection at each epoch. Large amplitudes imply that an event occurs with a spatial pattern similar to the target. We have applied the TPO technique to monitor surface deformation of Akutan volcano, Alaska, using GPS data from the Plate Boundary Observatory (PBO) stations collected during 2005-2016. The 2008 inflationary event was used as a target. We detected three inflationary events occurred in 2011, 2014 and 2016. The last event is larger than the first two but smaller than the 2008 event that has maximum horizontal displacement of about 9 mm. The three events are significant in TPO detection because changes in the amplitude of projection are larger than the root-mean-square (RMS) error from relatively quiet periods. A simple Mogi model, as well as the pattern similarity, indicates that the deformation source of Akutan volcano has remained stationary in space during the 11-year period of observation. However, the source has activated episodically as inflationary events, which suggests that magma has accumulated in the magma chamber continually and magma accumulation could eventually cause the next eruption.

  10. Direct constraints on GIA motion in North America using GPS (United States)

    Sella, G. F.; Stein, S.; Wdowinski, S.; Dixon, T. H.; Craymer, M.; James, T.


    We use continuous and episodic Global Positioning System (GPS) data to measure the movement caused by glacial isostatic adjustment (GIA) due to glacial unloading in eastern North America. At present it is challenging to quantify GIA motion in North American due to the limited number of continuous GPS sites (CGPS) in and around Hudson Bay, the area of maximum glacial loading. Episodic GPS (EGPS) sites provide a low cost and higher density alternative, but often have large errors, especially in the vertical. However, the large vertical signal due to GIA (>10mm/yr) in the area of maximum uplift permits this motion to be resolved, even with EGPS data. We present data from 130 CGPS sites throughout North America and almost 100 EGPS sites of the Canadian Base Network (CBN). The CBN sites are located across central and southern Canada and have been episodically occupied between 1994 and 2002. We detect a coherent pattern of vertical motions around the area of maximum glacial loading, Hudson Bay. The observed velocities are initially large and upward, and decrease southward from Hudson Bay to zero, delineating the hinge line near the Great Lakes. The position of the hinge line is in agreement with some numerical GIA predictions. The horizontal residual velocities after removing the motion of the rigid North American plate also show a consistent, but more complex pattern than the vertical velocities. In particular we observe larger than expected motions on the east side of the Canadian Rocky Mountains, possibly reflecting larger ice loads and/or changes in mantle viscosity. We believe that this velocity field provides the first comprehensive direct description of GIA motion and can be used to constrain GIA model predictions.

  11. Deporte con dispositivos de posicionamiento global (GPS: Aplicaciones y limitaciones

    Directory of Open Access Journals (Sweden)

    Julen Castellano


    Full Text Available En el presente documento se hace una revisión no exhaustiva sobre la aplicabilidad y limitaciones de los dispositivos GPS en el ámbito deportivo. En el trabajo se detallan aspectos claves que técnicos e investigadores deberían considerar para valorar los límites de su aplicabilidad al tiempo que maximizar su uso. Las temáticas que se abordan pueden concretarse es los siguientes: funcionamiento, limitaciones, diferentes usos motivados por la variedad en la tipología de variables que registra, oportunidades de sincronización con el vídeo o con la representación 2D del movimiento de los jugadores en el espacio (para posteriores análisis más pormenorizados, así como la disponibilidad de la información en ‘tiempo real’. Además, la tecnología GPS está dando sus primeros pasos para aportar información no solo de las demandas físicas o energéticas de los deportistas, sino también de las conductas colectivas que jugadores y equipos despliegan en sus actividades (partido, juegos reducidos, etc. Valoradas las limitaciones y valoradas sus aplicaciones los usuarios podrán beneficiarse de los dispositivos GPS cuando se apliquen al análisis del rendimiento en la competición y el entrenamiento. Esta tecnología puede ayudar a entrenadores y atletas en el desarrollo de sus trabajos o actividades con precisión, inmediatez y riqueza informacional.

  12. GPS Technology for the Development of Business Information Systems

    Directory of Open Access Journals (Sweden)

    Mihaela MURESAN


    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

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

    DEFF Research Database (Denmark)

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


    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...... 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...

  14. Ionospheric Mapping Software Ensures Accuracy of Pilots GPS (United States)


    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.

  15. GPS Navigation for the Magnetospheric Multi-Scale Mission (United States)

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


    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

  16. GPS-Aided Gyroscope-Free Inertial Navigation Systems


    Park, Sungsu; Tan, Chin-Woo


    A gyroscope-free inertial navigation system uses only accelerometers to compute navigation trajectories. It is a low-cost navigation system, but its output error diverges at a rate that is an order faster than that of a conventional gyroscope-based system. So integration with an external reference system, such as the Global Positioning System, is necessary for long-term navigation applications. In this pa-per, an integrated GPS and gyroscope-free INS system is designed to achieve stable long-...

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

    DEFF Research Database (Denmark)

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


    through medical treatment phrased in terms of either relative risk reduction, absolute risk reduction, number needed to treat or all of the aforementioned terms of risk reduction. The GPs were asked whether they would recommend medical treatment as primary prevention, knowing the case story and expected...... if information only about relative risk reduction was given, and 63% would recommend medication if information was given in terms of absolute risk reduction or number needed to treat. CONCLUSION: In order to advise patients in a rational way, in addition to knowledge of the patients' preferences, doctors need...

  18. GPS-Acoustic Seafloor Geodesy using a Wave Glider (United States)

    Chadwell, C. D.


    The conventional approach to implement the GPS-Acoustic technique uses a ship or buoy for the interface between GPS and Acoustics. The high cost and limited availability of ships restricts occupations to infrequent campaign-style measurements. A new approach to address this problem uses a remote controlled, wave-powered sea surface vehicle, the Wave Glider. The Wave Glider uses sea-surface wave action for forward propulsion with both upward and downward motions producing forward thrust. It uses solar energy for power with solar panels charging the onboard 660 W-h battery for near continuous operation. It uses Iridium for communication providing command and control from shore plus status and user data via the satellite link. Given both the sea-surface wave action and solar energy are renewable, the vehicle can operate for extended periods (months) remotely. The vehicle can be launched from a small boat and can travel at ~ 1 kt to locations offshore. We have adapted a Wave Glider for seafloor geodesy by adding a dual frequency GPS receiver embedded in an Inertial Navigation Unit, a second GPS antenna/receiver to align the INU, and a high precision acoustic ranging system. We will report results of initial testing of the system conducted at SIO. In 2014, the new approach will be used for seafloor geodetic measurements of plate motion in the Cascadia Subduction Zone. The project is for a three-year effort to measure plate motion at three sites along an East-West profile at latitude 44.6 N, offshore Newport Oregon. One site will be located on the incoming plate to measure the present day convergence between the Juan de Fuca and North American plates and two additional sites will be located on the continental slope of NA to measure the elastic deformation due to stick-slip behavior on the mega-thrust fault. These new seafloor data will constrain existing models of slip behavior that presently are poorly constrained by land geodetic data 100 km from the deformation front.

  19. The atmosphere- and hydrosphere-correlated signals in GPS observations (United States)

    Bogusz, Janusz; Boy, Jean-Paul; Klos, Anna; Figurski, Mariusz


    The circulation of surface geophysical fluids (e.g. atmosphere, ocean, continental hydrology, etc.) induces global mass redistribution at the Earth's surface, and then surface deformations and gravity variations. The deformations can be reliably recorded by permanent GPS observations nowadays. The loading effects can be precisely modelled by convolving outputs from global general circulation models and Green's functions describing the Earth's response. Previously published papers showed that either surface gravity records or space-based observations can be efficiently corrected for atmospheric loading effects using surface pressure fields from atmospheric models. In a similar way, loading effects due to continental hydrology can be corrected from precise positioning observations. We evaluated 3-D displacement at the selected ITRF2008 core sites that belong to IGS (International GNSS Service) network due to atmospheric, oceanic and hydrological circulation using different models. Atmospheric and induced oceanic loading estimates were computed using the ECMWF (European Centre for Medium Range Weather Forecasts) operational and reanalysis (ERA interim) surface pressure fields, assuming an inverted barometer ocean response or a barotropic ocean model forced by air pressure and winds (MOG2D). The IB (Inverted Barometer) hypothesis was classically chosen, in which atmospheric pressure variations are fully compensated by static sea height variations. This approximation is valid for periods exceeding typically 5 to 20 days. At higher frequencies, dynamic effects cannot be neglected. Hydrological loading were provided using MERRA land (Modern-Era Retrospective Analysis for Research and Applications - NASA reanalysis for the satellite era using a major new version of the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5)) for the different stations. After that we compared the results to the GPS-derived time series of North, East and Up components. The

  20. GPS observation of traveling ionospheric disturbances related to Moscow megacity (United States)

    Zakharov, V. I.; Gorchakov, G. I.


    We present the results of GPS-signal radio interferometry observations obtained in the period of summer 2010 (97 days) at the stations in the Moscow region. The stations belong to MNGS (Moscow Navigational and Geodetic Support) and IGS (International Geophysical Services) networks. We observed traveling ionospheric disturbances (TIDs) in a ring form around Moscow. Empirical functions of the parameters (motion speed and observation period) are obtained and discussed. It is shown that the observed distributions are manifestations of the acoustic-gravity waves and may be associated with a special heat regime, including the urban heat island established in the Moscow region during summer 2010 in the conditions of a blocking anticyclone.

  1. GPS Measurements Of The Relative Motion Between India And Sundaland (United States)

    Socquet, A.; Vigny, C.; Pubellier, M.; Chamot-Rooke, N.; Rangin, C.

    GPS measurements acquired in the framework of the GEODYSSEA project have pro- vided significant new information on the present day plate tectonics in South East Asia. In order to further investigate the relative motion between India and South East Asia, we have performed a combined processing the THAICA, APRGP, MYANMAR, GEODYSSEA and RTSD data (10 GPS campaigns from 1994 to 2000) including 90 stations in South East Asia. Global plate motion model Nuvel-1A [DeMets et al., 1994] predicts a relative motion of India with respect to Eurasia of about 5.5 cm/yr oriented around N20rE on the east- ern border of the Indian plate in Myanmar. Our geodetic results allow us to confirm That India motion is actually slower than this value in agreement with the results ob- tained by Paul et al., 2001. In addition, since the block along which India is sliding is not stable Eurasia but rather the Sundaland block [Michel et al., 2001], the relative motion expected between India and Sundaland on the Myanmar boundary reduces to about 4.5 cm/yr and rotates towards North. The local Myanmar velocity field [Vigny et al.,2001] show that, out of the 4.5 cm/yr of India versus Sundaland rate, only 3 cm/yr are accommodated in Myanmar, distributed between 2 cm/yr on the Sagaing fault and 1 cm/yr in the Myanmar Central Basins. Therefore, 1.5 cm/yr have to be taken elsewhere. Our results indicate that about 0.5 cm/yr can be accommodated in a large shear zone in Indochina, the remaining motion being accommodated in the Andaman trench. DeMets, C., R. G. Gordon, D. Argus, and S. Stein, Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions, Geophys. Res. Letters., 21, 2191-2194, 1994. Michel, G., Y. Yu, S. Zhu, C. Reigber, M. Becker, E. Reinhart, W. Simons, B. Am- brosius, C. Vigny, N. Chamot-Rooke, X. LePichon, P. Morgan, and S. Matheussen, Crustal motion and block behavior in SE-Asia from GPS measurements,.Earth and Physics Science letters, 187, 289

  2. Deporte con dispositivos de posicionamiento global (GPS): Aplicaciones y limitaciones


    Julen Castellano; David Casamichana


    En el presente documento se hace una revisión no exhaustiva sobre la aplicabilidad y limitaciones de los dispositivos GPS en el ámbito deportivo. En el trabajo se detallan aspectos claves que técnicos e investigadores deberían considerar para valorar los límites de su aplicabilidad al tiempo que maximizar su uso. Las temáticas que se abordan pueden concretarse es los siguientes: funcionamiento, limitaciones, diferentes usos motivados por la variedad en la tipología de variables que registra, ...

  3. Deporte con dispositivos de posicionamiento global (GPS) : aplicaciones y limitaciones


    Castellano, Julen


    En el presente documento se hace una revisión no exhaustiva sobre la aplicabilidad y limitaciones de los dispositivos GPS en el ámbito deportivo. En el trabajo se detallan aspectos claves que técnicos e investigadores deberían considerar para valorar los límites de su aplicabilidad al tiempo que maximizar su uso. Las temáticas que se abordan pueden concretarse es los siguientes: funcionamiento, limitaciones, diferentes usos motivados por la variedad en la tipología de variables que registra, ...

  4. GPS synchronized UV communication system performance based on USRP (United States)

    Liao, Linchao; Chen, Gang; Sadler, Brian M.; Li, Zening


    Recently, Ultraviolet communication is paid more and more attention, with its solar blind and Non-Line-of-Sight characteristic. However, it is hard to capture and recover the transmitted signal outdoor without synchronized signal. In this work, we integrate Universal Software Radio Peripheral (USRP) into UV communication system and employ GPS as synchronized signal. At receive side, photon counting and adaptive threshold method are used to recover original signal. Through experiments, we test path loss and BER of the system under di erent con guration geometries. Some results are compared to the previous proposed path loss and BER models.

  5. Navigation GPS/GLONASS in the Arctic and aurora

    Directory of Open Access Journals (Sweden)

    Chernouss S. A.


    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.

  6. Network management tools for a GPS datalink network (United States)

    Smyth, Padhraic; Chauvin, Todd; Oliver, Gordon; Statman, Joseph


    The availability of GPS (Global Position Satellite) information in real-time via a datalink system is shown to significantly increase the capacity of flight test and training ranges in terms of missions supported. This increase in mission activity. imposes demands on mission planning in the range-operations environment. In this context, network management tools which can improve the capability of range personnel to plan, monitor, and control network resources, are of significant interest. The application of both simulation and artificial intelligence techniques is described to develop such network managements tools.

  7. GPS - PET : aplicación web para la geolocalización de mascotas


    Pérez Alonso, Rebeca Escarlata


    [ES]Este proyecto trata de desarrollar una aplicación web en Ruby on Rails, donde el usuario pueda visualizar en “tiempo real” la ubicación de su animal haciendo uso de su identificador con GPS (microchip con GPS), si existiera tal dispositivo, o un dispositivo de geolocalización GPS incrustado en el collar del perro, para hacer un seguimiento del mismo cuando otra persona que ha sido contratada lo pasea. Al no disponer de microchips o collares con GPS, así como los respectivos animales para ...

  8. GPs working in solo practice: obstacles and motivations for working in a group? A qualitative study. (United States)

    Feron, Jean-Marc; Cerexhe, Françoise; Pestiaux, Dominique; Roland, Michel; Giet, Didier; Montrieux, Christian; Paulus, Dominique


    Our aim was to analyse the obstacles and eventual motivations of solo GPs for working in group practice. A qualitative study using 12 focus groups was carried out in primary care in French-speaking Belgium. The subjects comprised four samples of GPs: 20 GP trainers, 18 GP trainees, 25 women GPs and 25 other GPs. The focus groups were taped and transcribed. Two independent researchers carried out the analysis using the QSR NUD.IST software. The participants (88 GPs) did not share a common definition of group practice-in particular multidisciplinary working-the need for a common pool of patients and shared premises. Their main sources of motivation for eventually setting up a group practice were better quality of life, continuity of care and sharing professional knowledge. The main obstacles were a required agreement between colleagues, the loss of a personal patient-GP relationship, budgetary constraints, and divergent views on group practice and GPs' profession (especially true for the association of GPs from different age groups). The current study shows that GPs working solo have divergent views of group practice. However, they clearly perceive advantages to this type of association (e.g. better quality of life and continuity of care). This study also confirms the high level of stress and tiredness felt by GPs and especially senior practitioners.

  9. Concurrent Validity of GPS for Deriving Mechanical Properties of Sprint Acceleration. (United States)

    Nagahara, Ryu; Botter, Alberto; Rejc, Enrico; Koido, Masaaki; Shimizu, Takeshi; Samozino, Pierre; Morin, Jean-Benoit


    To test the concurrent validity of data from 2 different global positioning system (GPS) units for obtaining mechanical properties during sprint acceleration using a field method recently validated by Samozino et al. Thirty-two athletes performed maximal straight-line sprints, and their running speed was simultaneously measured by GPS units (sampling rate: 20 or 5 Hz) and either a radar or laser device (devices taken as references). Lower-limb mechanical properties of sprint acceleration (theoretical maximal force, theoretical maximal speed, maximal power) were derived from a modeling of the speed-time curves using an exponential function in both measurements. Comparisons of mechanical properties from 20- and 5-Hz GPS units with those from reference devices were performed for 80 and 62 trials, respectively. The percentage bias showed a wide range of overestimation or underestimation for both systems (-7.9% to 9.7% and -5.1% to 2.9% for 20- and 5-Hz GPS), while the ranges of its 90% confidence limits for 20-Hz GPS were markedly smaller than those for 5-Hz GPS. These results were supported by the correlation analyses. Overall, the concurrent validity for all variables derived from 20-Hz GPS measurements was better than that obtained from the 5-Hz GPS units. However, in the current state of GPS devices' accuracy for speed-time measurements over a maximal sprint acceleration, it is recommended that radar, laser devices, and timing gates remain the reference methods for implementing the computations of Samozino et al.

  10. Synthesis Analysis of One Severe Convection Precipitation Event in Jiangsu Using Ground-Based GPS Technology

    Directory of Open Access Journals (Sweden)

    Hao Wang


    Full Text Available Global positioning system (GPS detection technology has several advantageous characteristics (i.e., all-weather applications, high accuracy, high spatial and temporal resolution, and low cost, and GPS tracking and monitoring techniques for water vapor have developed rapidly in recent years. The GPS-precipitable water vapor (GPS-PWV, obtained through inversion using this technology can reflect the water vapor inflow and outflow in a vertical air column above a certain area in nearly real-time, which is especially important for areas of severe water vapor variation. In this paper, we studied the relationship between GPS-PWV variation and actual precipitation. The specific aim was to identify the underlying physical mechanisms driving the variation and to further strengthen the utility of GPS-PWV in forecasts and warnings of severe convection weather. We concluded that (1 rapid rise in the GPS-PWV in the long-term low-level data predicted the arrival of precipitation and was therefore useful in weather forecasts; (2 the GPS-PWV variation was closely related with the movement of the water vapor transfer belt; (3 the atmosphere showed an unstable energy structure before the GPS-PWV increase; and (4 local motion was strongly related with the development and maintenance of precipitation.

  11. Regional and Local Geoid Undulations for Computing Orthometric Heights from GPS Measurements Project (United States)

    National Aeronautics and Space Administration — This proposal explains procedures of using regional and local geoid undulations to improve and convert the global positioning system (GPS) elevations (ellipsoidal...

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

    DEFF Research Database (Denmark)

    Jensen, Kjeld; Larsen, Morten; Simonsen, Tom


    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...

  13. Prevalence and predictors of occupational violence and aggression towards GPs: a cross-sectional study. (United States)

    Koritsas, Stella; Coles, Jan; Boyle, Malcolm; Stanley, Janet


    Occupational violence and aggression are common in general practice. This study examined occupational violence and aggression against GPs in terms of prevalence and predictive factors, such as sex of GP, and practice location. Over half of the GPs sampled had experienced at least one form of violence and aggression; more female than male GPs experienced sexual harassment; and there was no difference in the number of metropolitan and rural GPs who had experienced violence and aggression. Predictors emerged for verbal abuse, intimidation, physical abuse, and sexual harassment.

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

    Directory of Open Access Journals (Sweden)

    Krzysztof Bikonis


    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.

  15. Investigating mass loading contributes of annual GPS observations for the Eurasian plate (United States)

    Li, Zhen; Yue, Jianping; Li, Wang; Lu, Dekai


    Singular spectrum analysis (SSA) is a non-parametric method, which outperforms least-squares fitting (LSF) in extracting amplitude and phase varying seasonal oscillations in GPS observations. Meanwhile, it is well known that the variations of regional mass loading (atmospheric, oceanic and hydrological loading (AOHL)), as potential contributors, are very important for understanding time-varying seasonal fluctuations in GPS station heights. We thus use SSA to extract the annual signals from the time series of GPS station heights and AOHL deformation, respectively. The result reveals whether AOHL is able to explain the annual fluctuations in GPS station heights depends on the relative phasing between the two time series. Therefore, the cross wavelet transform based (XWT-based) semblance analysis is adopted to investigate the phase relationship between GPS station heights and AOHL deformation. The result of the XWT-based semblance analysis indicates that the annual variations in the two time series are physically related for most sites; other geophysical effects, GPS systematic errors and AOHL modeling errors could result in the time-varying phasing asynchrony for some sites. The phasing asynchrony confirms that the annual oscillation in GPS station heights results from a combination of mass loading and systematic errors. Moreover, for the sites where the phase asynchrony is obvious, we propose to employ SSA to denoise GPS observations since SSA perform better than AOHL deformation in reducing the RMS of GPS observations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Maulida, Putra, E-mail: [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)


    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.

  17. How do rural GPs manage their inactive and overweight patients?--A pilot study of rural GPs in Queensland. (United States)

    Eley, Diann S; Eley, Robert M


    Overweight and obesity are major risk factors for chronic disease. Physical activity plays an important role in increasing wellbeing and reducing weight. General practitioners' advice and intervention can help patients increase their physical activity. This pilot study is part of a larger study investigating physical activity opportunities in rural Queensland. A survey was sent to a random sample of 40 general practices in rural Queensland. The survey asked GPs about strategies they use when dealing with patients who would benefit from exercise, their use of Lifescripts, the main perceived barriers to exercise in their location, perceptions on change in exercise patterns over 5 years, and local resources and referral networks available in their location. The data was analysed using a five stage framework and coded into themes. A total of 67.5% of practices responded. The primary strategy GP respondents used to address overweight was discussion and advice. Fifteen of the 27 respondents referred patients to allied health professionals and local sport/recreation organisations. Lack of physical and human resources to encourage and support weight loss was the main perceived barrier to helping patients achieve physical activity and weight loss goals. Behavioural factors are globally acknowledged as the biggest barriers to exercise. The GPs surveyed recognise that, for most people, external support is essential for ongoing exercise compliance and motivation. This can be in the form of discussion with, and advice from, the GP, or referral to gyms or other services. Respondents identified limited facilities and support in rural areas as barriers. Formalisation of referral pathways and follow up is currently lacking and could assist rural GPs in helping their patients to exercise and lose weight.

  18. Aplikasi Peta ATM Dengan Menggunakan Aplikasi GPS Pada Handphone Android

    Directory of Open Access Journals (Sweden)

    Tantan Taryono


    Full Text Available Seiring meningkatnya mobilitas masyarakat dan tingginya kebutuhan informasi berupa peta, Geographic Information System (GIS bukan hanya sekadar tren teknologi, tetapi telah menjadi sebuah kebutuhan. Ketatnya persaingan para vendor perangkat bergerak (mobile device dengan berbagai fitur dan keunggulan, secara tidak langsung berdampak positif bagi konsumen teknologi  mobile salah satunya operating system (OS Android. Dengan adanya operating system (OS Android yang memberikan banyak keuntungan salah satunya adalah OS Android yang bersifat open source, para pengembang aplikasi Android dapat membuat sebuah aplikasi sesuai kebutuhan termasuk pembuatan aplikasi Peta ATM. Disamping itu pada handphone Android juga telah tersedia GPS sebagai penetuan posisi pengguna. Peta ATM dengan menggunakan aplikasi GPS merupakan sebuah aplikasi yang dapat digunakan oleh banyak kalangan. Banyak manfaat yang dapat dirasakan dengan menggunakan aplikasi ini, diantaranya adalah dengan mengetahui sebuah lokasi dimana posisi user berada. Begitu juga dengan aplikasi peta Automatic Teller Machine (ATM dapat memberikan kemudahan bagi para pengguna handphone berbasis operating system Android untuk mengetahui dimana letak posisi ATM BNI yang berada di wilayah Purwokerto dan sekitarnya. Dengan adanya aplikasi peta ATM BNI diharapkan para pengguna yang belum mengetahui secara lengkap kota Purwokerto dapat dengan mudah dalam mencari lokasi ATM.

  19. Uncovering urban human mobility from large scale taxi GPS data (United States)

    Tang, Jinjun; Liu, Fang; Wang, Yinhai; Wang, Hua


    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.

  20. GPS-based Microenvironment Tracker (MicroTrac) Model to ... (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

  1. First GPS measurements across the Central-Western Mediterranean area

    Directory of Open Access Journals (Sweden)

    N. Saadi


    Full Text Available This paper concerns the displacement field of the central-western part of the Mediterranean basin estimated by the analysis of three repeated GPS surveys (1995, 1996 and 1997 consisting of 8 sites of a network. This network includes for the first time the stations of Algiers and Arzew, located in Northern Algeria, an area not yet investigated by regional GPS surveys. Lampedusa station is located in the Sicily Straits rifting area while the other five stations of Cagliari, Wettzell, Madrid, Matera and Noto belong to the IGS permanent tracking network. The statistical analysis of 1995, 1996 and 1997 data show significant displacements at five stations. The displacement vectors of the African sites show a convergence between the African and the Eurasian plates at a rate of 0.8 ± 0.4 cm within a two year time span. A comparison between the displacements estimated in the present work and the ITRF96 determinations for the five permanent stations allow us to evaluate the motion of Lampedusa, Algiers and Arzew in the IERS Terrestrial Reference System.

  2. Updating Road Networks by Local Renewal from GPS Trajectories

    Directory of Open Access Journals (Sweden)

    Tao Wu


    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.

  3. Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements (United States)

    Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.


    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.

  4. Newly velocity field of Sulawesi Island from GPS observation (United States)

    Sarsito, D. A.; Susilo, Simons, W. J. F.; Abidin, H. Z.; Sapiie, B.; Triyoso, W.; Andreas, H.


    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.

  5. Habitat Selection and Activity Pattern of GPS Collared Sumateran Tigers

    Directory of Open Access Journals (Sweden)

    Dolly Priatna


    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

  6. The gravity persistent signal (gps) Mutants of Arabidopsis: Insights into Gravitropic Signal Transduction (United States)

    Wyatt, S.

    The gravitropic response of Arabidopsis stems is rapid with a visible within 30 min and vertical reorientation within 2 h. However, horizontal gravistimulation for 3 h at 4°C does not cause curvature. When the stems are subsequently placed in the vertical position at RT, they bend in response to the previous, horizontal gravistimulation. These results indicate that the gravity perception step can occur at 4°C, but that part of the response is sensitive to cold. At 4°C, starch-containing amyloplasts in the endodermis of the inflorescence stems sedimented normally but auxin transport was abolished indicating that the cold treatment affected early events of the signal transduction pathway that occur after amyloplast sedimentation but prior to auxin transport. The gps mutants of Arabidopsis are a unique group of mutants that respond abnormally after gravistimulation at 4°C. gps1 shows no response to the cold gravistimulation, gps2 bends the wrong way as compared to wild type and gps3 over responds, bending past the anticipated curvature. The mutants were selected from a T-DNA tagged population. Cloning strategies based on the tag have been employed to identify the genes disrupted. GPS1 was cloned using TAIL PCR and is At3g20130, a cytochrome P450, CYP705A22, of unknown function. GPS1p::GFP fusions are being used to determine temporal and spatial expression of GPS1. The mutation in gps3 appears to disrupt a non-coding region downstream of At1g43950 No function has yet been determined for this region, but it appears that the mutation disrupts transcription of a transcription factor homologous to the DNA binding domain of an auxin response factor (ARF) 9-like protein. The identity of GPS2 is as yet unknown. The gps mutants represent potentially three independent aspects of signal transduction in the gravitropic response: perception or retention of the gravity signal (gps1), determination of the polarity of the response (gps2), and the tissue specificity of the

  7. GPS Application for Groundwater Resource Assessment, Hermanus, South Africa (United States)

    Hartnady, C.; Mlisa, A.; Wonnacott, R.; Calais, E.


    TrigNet ( is a network of permanent continuously operating GPS (cGPS) base stations distributed throughout South Africa at approximately 200 - 300 km spacing. Data from 21 of the stations is continuously streamed to the TrigNet control centre in the offices of the Chief Directorate: Surveys and Mapping, from where it is made available within 30 minutes after each hour for 24 hours a day. All stations record 1-second epoch data on both GPS frequencies (L1 and L2) through geodetic-standard choke ring antennas. The real-time Trignet station HERM is situated in the grounds of the Hermanus Magnetic Observatory (HMO), in a coastal town about 100 km SW of the City of Cape Town. The Overstrand Municipality of the Greater Hermanus Area has embarked on a major groundwater development to augment the water supply. As a foundation for sustainable management of the groundwater resource, a detailed monitoring programme was developed for a better understanding of the hydraulic system, and of the interconnections between surface water, the shallow primary aquifer and the remarkable, deep, fractured-rock (FR) aquifer of the Table Mountain Group (TMG), which underlies a large part of the Western Cape province in South Africa. A thick, extensive FR aquifer system like the ~1 km thick Peninsula Aquifer in the TMG provides an opportunity for fundamental advances in understanding interactions between fluid flow and mechanical deformation, through analysis of the "hydro-mechanical" coupling in FR permeability, fluid transport and deep storage in FR porosity. Present knowledge of skeletal-framework compressibility, the main factor in specific storage, is based on published data from similar rocks elsewhere. Up-scaling from dry-sample laboratory measurements of elastic properties of borehole-core samples at ~10-cm scale to saturated rock volumes on 100- to 1000-m scale, is methodologically problematic. Measuring directly the compaction of, and

  8. From Transit to Galileo via GPS/GLONAS and EGNOS (United States)

    Rosetti, Calin


    The need for satellite navigation came out of military requirements in the early 1960's. The first system of this kind was TRANSIT.It was more a positioning rather than true navigation system. The satellites were well designed and remained operational long over their target life time.The two signals were in the VHF frequency range.At a certain moment the usage of TRANSIT was released for the civilian maritime community.The system has provided a limited but useful service for almost 30 years.The program was decommissioned by the end 0f 1996. Meanwhile the development of technology, in particular space qualified atomic clocks opened the possibility to design and fly systems with largely improved performance and true precision navigation capabillity, fullfiling a broad range of new military requirements (missile guidance,in flight refuelling,guided bombs etc). The first system of this kind was NAVSTAR/GPS.The Block 1 demonstration configuration was launched between early 1978 and late 1985 (11 satellites).It was followed immediately by the operational Block 2, completing the initial Block 1 with 27 satellites launched between early 1989 and end of 1996.The full 24 satellite constellation was completed in early 1994. GPS transmits the navigation service on two L-band frequencies.The coarse acquisition code C/A is intended for civilian use as well,but without any guarantee of continuous availability or precision.Moreover the C/A code was long time deliberately degraded(selective availability).This degradation gave the impetus in Europe to start in the early 1980's the design and development of the system known as EGNOS. The European Geostationnary Navigation Overlay System.Similar systems were developed subsequently in other parts of the world(WAAS/MSAS etc.) It might be this very fact who helped the responsible US authorities to give up the selective availability of the C/A code in May 2000. More or less at the same time begun in the USSR the design and development of

  9. Evaluation of micro-GPS receivers for tracking small-bodied mammals. (United States)

    McMahon, Laura A; Rachlow, Janet L; Shipley, Lisa A; Forbey, Jennifer S; Johnson, Timothy R; Olsoy, Peter J


    GPS telemetry markedly enhances the temporal and spatial resolution of animal location data, and recent advances in micro-GPS receivers permit their deployment on small mammals. One such technological advance, snapshot technology, allows for improved battery life by reducing the time to first fix via postponing recovery of satellite ephemeris (satellite location) data and processing of locations. However, no previous work has employed snapshot technology for small, terrestrial mammals. We evaluated performance of two types of micro-GPS (GPS errors might influence fine-scale assessments of space use and habitat selection. During stationary tests, microtopography (i.e., burrows) and satellite geometry had the largest influence on GPS fix success rate (FSR) and location error (LE). There was no difference between FSR while animals wore the GPS collars above ground (determined via light sensors) and FSR generated during stationary, above-ground trials, suggesting that animal behavior other than burrowing did not markedly influence micro-GPS errors. In our study, traditional micro-GPS receivers demonstrated similar FSR and LE to snapshot receivers, however, snapshot receivers operated inconsistently due to battery and software failures. In contrast, the initial traditional receivers deployed on animals experienced some breakages, but a modified collar design consistently functioned as expected. If such problems were resolved, snapshot technology could reduce the tradeoff between fix interval and battery life that occurs with traditional micro-GPS receivers. Our results suggest that micro-GPS receivers are capable of addressing questions about space use and resource selection by small mammals, but that additional techniques might be needed to identify use of habitat structures (e.g., burrows, tree cavities, rock crevices) that could affect micro-GPS performance and bias study results.

  10. GPs' mental wellbeing and psychological resources: a cross-sectional survey. (United States)

    Murray, Marylou Anna; Cardwell, Chris; Donnelly, Michael


    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 GPs have levels of positive 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.

  11. A Forward GPS Multipath Simulator Based on the Vegetation Radiative Transfer Equation Model. (United States)

    Wu, Xuerui; Jin, Shuanggen; Xia, Junming


    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.

  12. Design of complete software GPS signal simulator with low complexity and precise multipath channel model

    Directory of Open Access Journals (Sweden)

    G. Arul Elango


    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.

  13. Dynamic accuracy of GPS receivers for use in health research: a novel method to assess GPS accuracy in real-world settings

    DEFF Research Database (Denmark)

    Schipperijn, Jasper; Kerr, Jacqueline; Duncan, Scott


    was to test the dynamic accuracy of a portable GPS device under real-world environmental conditions, for four modes of transport, and using three data collection intervals. We selected four routes on different bearings, passing through a variation of environmental conditions in the City of Copenhagen, Denmark......The emergence of portable global positioning system (GPS) receivers over the last 10 years has provided researchers with a means to objectively assess spatial position in free-living conditions. However, the use of GPS in free-living conditions is not without challenges and the aim of this study...... be taken when the environment in which the study takes place could compromise the GPS signal....

  14. GPs' explanatory models for irritable bowel syndrome : a mismatch with patient models?

    NARCIS (Netherlands)

    Casiday, Rachel E.; Hungin, A. P. S.; Cornford, Charles S.; de Wit, Niek J.; Blell, Mwenza T.

    Background. Inconsistencies in doctors' views about causes and treatment of irritable bowel syndrome (IBS) lead to frustration for doctors and in doctor-patient interactions. Diagnosis by GPs does not correspond well to established diagnostic criteria. Objective. To understand GPs' explanatory

  15. Euthanatics: implementation of a protocol to standardise euthanatics among pharmacists and GPs

    NARCIS (Netherlands)

    Philipsen, B.D.; Muller, M.T.; van der Wal, G.


    The purpose of this study was to evaluate the implementation of a protocol to standardise euthanatics among pharmacists and general practitioners (GPs). Data over 1993 and 1994 were collected by means of an anonymous postal questionnaire sent to all pharmacists (n = 37) and all GPs (n = 283) working

  16. GPs' experiences of children with anxiety disorders in primary care: a qualitative study. (United States)

    O'Brien, Doireann; Harvey, Kate; Young, Bridget; Reardon, Tessa; Creswell, Cathy


    Anxiety disorders have a median age of onset of 11 years and are the most common emotional disorders in childhood; however, a significant proportion of those affected do not access professional support. In the UK, GPs are often the first medical professional that families see so are in a prime position to support children with anxiety disorders; however, currently there is little research available on GPs' perspectives on and experiences of supporting children with these disorders. To explore the experiences of GPs in relation to identification, management, and access to specialist services for children (GPs in primary care throughout England. GPs reflected a diverse group in relation to the ethnic and socioeconomic profile of registered patients, GP age, sex, professional status, previous engagement with research, and practice size and location. Purposive sampling was used to recruit GPs until theoretical saturation was reached. Data were analysed using a constant comparative method of thematic analysis. Data from 20 semi-structured interviews were organised into three themes: decision making, responsibility, and emotional response, with an overarching theme of GPs feeling ill equipped. These themes were retrospectively analysed to illustrate their role at different stages in the primary care process (identification, management, and access to specialist services). GPs feel ill equipped to manage and support childhood anxiety disorders, demonstrating a need for medical training to include greater emphasis on children's mental health, as well as potential for greater collaboration between primary and specialist services. © British Journal of General Practice 2017.

  17. 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.

  18. GPs' experiences with enhanced collaboration between psychiatry and general practice for children with ADHD

    NARCIS (Netherlands)

    Hassink-Franke, L.J.A.; Janssen, M.M.M.; Oehlen, G.; Deurzen, P.A.M. van; Buitelaar, J.K.; Wensing, M.; Lucassen, P.L.B.J.


    BACKGROUND: Most general practitioners (GPs) do not feel comfortable with diagnosing and treating children with attention deficit hyperactivity disorder (ADHD). This is problematic since ADHD is a prevalent disorder and an active role of GPs is desired. In the Netherlands a collaborative ADHD

  19. Characterizing the spatial and temporal activities of free-ranging cows from GPS data (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 ...

  20. How do GPs in Switzerland perceive their patients' satisfaction and expectations? An observational study. (United States)

    Sebo, Paul; Herrmann, François R; Haller, Dagmar M


    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 (pGPs' 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

  1. 77 FR 808 - Certain Components for Installation of Marine Autopilots With GPS or IMU; Termination of... (United States)


    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Components for Installation of Marine Autopilots With GPS or IMU; Termination of... components for installation of marine autopilots with GPS or IMU (i.e., devices for pointing and stabilizing...

  2. Ionospheric Behaviors Over Korea Peninsula During the Super Geomagnetic Storm Using GPS Measurements

    Directory of Open Access Journals (Sweden)

    Jong-Kyun Chung


    Full Text Available The super-geomagnetic storms called 2003 Halloween event globally occurred during the period of 29 through 31 which are the following days when the solar flares of X18 class exploded on 28 October 2003. The S4 index from GPS signal strength and the peak electron density (NmF2 from GPS tomography method are analyzed according to the date. The occurrences of the cycle slip and scintillation in the GPS signals are 1,094 and 1,387 on 28 and 29 October, respectively and these values are higher than 604 and 897 on 30 and 31 October. These mean the ionospheric disturbances are not always generated by the period of geomagnetic storm. Therefore, GPS S4 index is useful to monitor the ionospheric disturbances. Behaviors of ionospheric electron density estimated from GPS tomography method are analyzed with the date. At UT = 18 hr, the maximum NmF2 is shown on 28 October. It agrees with NmF2 variation measured from Anyang ionosonde, and the GPS signal are better condition on 30 and 31 October than 28 October. In conclusion, GPS signal condition is relation with geomagnetic activities, and depend upon the variation of the electron density. We will study the long-term data to examine the relationship between the GPS signal quality and the electron density as the further works.

  3. Human factors evaluation of TSO-C129A GPS receivers (United States)


    This report documents an evaluation of the usability of TSO-C129a-certified Global Positioning System (GPS) receivers. Bench and flight tests were conducted on six GPS receivers. The evaluations covered 23 flight tasks. Both subjective and objective ...

  4. 78 FR 57672 - 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS) (United States)


    .... Paige Williams, Management Analyst, NextGen, Business Operations Group, Federal Aviation Administration... Federal Aviation Administration 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS... Notice of RTCA Special Committee 159, RTCA Special Committee 159, Global Positioning Systems (GPS...

  5. Een vergelijking van de voorjaarstrek van drie populaties Brandganzen met behulp van GPS-satellietzenders

    NARCIS (Netherlands)

    De Boer, R.; Bauer, Silke; Van der Jeugd, Henk; Ens, B.J.; Griffin, L.; Cabot, D.; Exo, K-M.; Nolet, Bart A.; Kölzsch, Andrea


    Onderzoek naar trekvogels heeft een grote vlucht genomen sinds de introductie van draagbare apparatuur met ingebouwde GPS-ontvangers, omdat we hiermee de trek van individuele vogels in groot detail kunnen volgen. In dit artikel brengen we met behulp van GPS-satellietzenders de voorjaarstrek van drie

  6. Reliability and Accuracy of 10 Hz GPS Devices for Short-Distance Exercise

    National Research Council Canada - National Science Library

    Castellano, Julen; Casamichana, David; Calleja-González, Julio; Román, Jaime San; Ostojic, Sergej M


    ... and accuracy of GPS devices using a sampling frequency of 10 Hz. Thus, the aim of the present research was to determine the reliability and accuracy of GPS devices operating at a sampling frequency of 10 Hz, in relation here to sprints of 15 m and 30 m and using both video and photoelectric cells. Nine trained male athletes participated in the study....

  7. 76 FR 12133 - In the Matter of Certain GPS Devices and Products Containing Same; Enforcement Proceeding... (United States)


    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain GPS Devices and Products Containing Same; Enforcement Proceeding... importation of certain GPS devices and products containing the same by reason of infringement of various...

  8. Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting

    Directory of Open Access Journals (Sweden)

    K. Boniface


    Full Text Available Impact of GPS (Global Positioning System data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day long assimilation cycles prior each of the two studied events. The results of these assimilation cycles show that the assimilation of GPS ZTD with the AROME system performs well in producing analyses closer to the ZTD observations in average. Then the impacts of assimilating GPS data on the precipitation forecast have been evaluated. For the first case, only the AROME runs starting a few hours prior the triggering of the convective system are able to simulate the convective precipitation. The assimilation of GPS ZTD observations improves the simulation of the spatial extent of the precipitation, but slightly underestimates the heaviest precipitation in that case compared with the experiment without GPS. The accuracy of the precipitation forecast for the second case is much better. The analyses from the control assimilation cycle provide already a good description of the atmosphere state that cannot be further improved by the assimilation of GPS observations. Only for the latest day (22 November 2007, significant differences have been found between the two parallel cycles. In that case, the assimilation of GPS ZTD allows to improve the first 6 to 12 h of the precipitation forecast.

  9. Where on Earth am I? Don't Worry, GPS Satellites will Guide you ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 8. Where on Earth am I? Don't Worry, GPS Satellites will Guide you - Introduction and Principle of GPS. Makarand Phatak. General Article Volume 3 Issue 8 August 1998 pp 25-32 ...

  10. Where on Earth am I? Don't Worry,. GPS Satellites will Guide you

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 9. Where on Earth am I? Don't Worry, GPS Satellites will Guide you - Mechanisms and Uses of GPS. Makarand Phatak. General Article Volume 3 Issue 9 September 1998 pp 14-25 ...

  11. Impact of high-resolution data assimilation of GPS zenith delay on Mediterranean heavy rainfall forecasting

    Energy Technology Data Exchange (ETDEWEB)

    Boniface, K.; Champollion, C.; Chery, J.; Doerflinger, E. [Geosciences Montpellier, UMR 5243 CNRS-UM2 (France); Ducrocq, V.; Jaubert, G.; Yan, X.; Brousseau, P. [GAME-CNRM, CNRS-Meteo-France, Toulouse (France); Masson, F. [UMR 7516-IPGS-CNRS-EOST, Strasbourg (France)


    Impact of GPS (Global Positioning System) data assimilation is assessed here using a high-resolution numerical weather prediction system at 2.5 km horizontal resolution. The Zenithal Tropospheric Delay (ZTD) GPS data from mesoscale networks are assimilated with the 3DVAR AROME data assimilation scheme. Data from more than 280 stations over the model domain have been assimilated during 15-day long assimilation cycles prior each of the two studied events. The results of these assimilation cycles show that the assimilation of GPS ZTD with the AROME system performs well in producing analyses closer to the ZTD observations in average. Then the impacts of assimilating GPS data on the precipitation forecast have been evaluated. For the first case, only the AROME runs starting a few hours prior the triggering of the convective system are able to simulate the convective precipitation. The assimilation of GPS ZTD observations improves the simulation of the spatial extent of the precipitation, but slightly underestimates the heaviest precipitation in that case compared with the experiment without GPS. The accuracy of the precipitation forecast for the second case is much better. The analyses from the control assimilation cycle provide already a good description of the atmosphere state that cannot be further improved by the assimilation of GPS observations. Only for the latest day (22 November 2007), significant differences have been found between the two parallel cycles. In that case, the assimilation of GPS ZTD allows to improve the first 6 to 12 h of the precipitation forecast. (orig.)

  12. Obstacles to the delivery of primary palliative care as perceived by GPs.

    NARCIS (Netherlands)

    Groot, M.M.; Vernooij-Dassen, M.J.F.J.; Verhagen, C.A.H.H.V.; Crul, B.J.P.; Grol, R.P.T.M.


    INTRODUCTION: In order to facilitate GPs in their work and increase the possibilities for patients to remain at home, it is important to identify the obstacles which hinder the delivery of primary palliative care. From previous research we learned about some of the problems experienced by GPs. In

  13. A Newly Reanalyzed Dataset of GPS-determined Antarctic Vertical Rates (United States)

    Thomas, I.; King, M.; Clarke, P. J.; Penna, N. T.; Lavallee, D. A.; Whitehouse, P.


    Accurate and precise measurements of vertical crustal motion offer useful constraints on glacial isostatic adjustment (GIA) models. Here we present a newly reprocessed data set of GPS-determined vertical rates for Antarctica. We give details of the global reanalysis of 15-years of GPS data, the overarching aim of which is to achieve homogeneous station coordinate time series, and hence surface velocities, for GPS receivers that are in regions of GIA interest in Antarctica. The means by which the reference frame is realized is crucial to obtaining accurate rates. Considerable effort has been spent on achieving a good global distribution of GPS stations, using data from IGS and other permanently recording stations, as well as a number of episodic campaigns in Antarctica. Additionally, we have focused on minimizing the inevitable imbalance in the number of sites in the northern and southern hemispheres. We align our daily non-fiducial solutions to ITRF2005, i.e. a CM frame. We present the results of investigations into the reference frame realization, and also consider a GPS-derived realization of the frame, and its effect on the vertical velocities. Vertical velocities are obtained for approximately 40 Antarctic locations. We compare our GPS derived Antarctic vertical rates with those predicted by the Ivins and James and ICE-5G models, after converting to a CE frame. We also compare to previously published GPS rates. Our GPS velocities are being used to help tune, and bound errors of, a new GIA model also presented in this session.

  14. A decade of GPS in Southeast Asia : Resolving Sundaland motion and boundaries

    NARCIS (Netherlands)

    Simons, W.J.F.; Socquet, A.; Vigny, C.; Ambrosius, B.A.C.; Haji Abu, S.; Promthong, C.; Subarya, C.; Sarsito, D.A.; Matheussen, S.; Morgan, P.; Spakman, W.


    A unique GPS velocity field that spans the entire Southeast Asia region is presented. It is based on 10 years (1994–2004) of GPS data at more than 100 sites in Indonesia, Malaysia, Thailand, Myanmar, the Philippines, and Vietnam. The majority of the horizontal velocity vectors have a demonstrated

  15. Design of GPS-GPRS module for localization vehicles and cargo

    Directory of Open Access Journals (Sweden)



    Full Text Available In the paper are presented results of market researches of logisticenterprises in Upper Silesia region which determine the level of implementation of GPS systems in vehicles. The results of that research implied design of GPS-GPRS module to be applied in vehicles as an alternative solution for modules already present on the market.

  16. Impact of spirometry on GPs' diagnostic differentiation and decision-making.

    NARCIS (Netherlands)

    Chavannes, N.H.; Schermer, T.R.J.; Akkermans, R.P.; Jacobs, J.E.; Graaf, G. van de; Bollen, R.; Schayck, C.P. van; Bottema, B.J.A.M.


    BACKGROUND: Spirometry is increasingly implemented in general practice, while the ability of general practitioners (GPs) to interpret flow volume curves (F-V curves) has been questioned. Furthermore, the role of spirometry in the GPs decision-making process has barely been studied. AIM: To compare

  17. GPS sensing of precipitable water vapour during the March 2010 Melbourne storm (United States)

    Choy, S.; Wang, C.; Zhang, K.; Kuleshov, Y.


    The March 2010 Melbourne storm is used as a case study to examine the potential of using Global Positioning System (GPS) observations for studying the precipitable water vapour (PWV) field. The Victorian statewide GPS infrastructure network, i.e. GPSnet, was used in this study. GPSnet is currently the only statewide and densest GPS infrastructure network in Australia, which provides an excellent opportunity to examine the distribution of water vapour as the severe weather system passed over the state. Data from 15 GPSnet stations were processed over a one-week period, i.e. a few days prior to and after the storm passage, during which the course of the storm extended from the west to the southeast corner of the state. In addition, data from two radiosonde sites of the Australian Bureau of Meteorology Upper Air Network were used to compare and validate the GPS derived PWV measurements. The findings demonstrate that there is strong spatial and temporal correlation between variations of the ground-based GPS-PWV estimates and the passage of the storm over the state. This is encouraging as the ground-based GPS water vapour sensing technique can be considered as a supplemental meteorological sensor in studying severe weather events. The advantage of using ground-based GPS-PWV technique is that it is capable of providing continuous observation of the storm passage with high temporal resolution. The spatial resolution of the distribution of water vapour is dependent on the geographical location and density of the GPS stations.

  18. Assessing people travel behavior using GPS and open data to validate neighbourhoods characteristics

    NARCIS (Netherlands)

    Oliveti, M; van der Spek, S.C.; Quak, C.W.; Sarjakoski, T.; Santos, M.Y.; Sarjakoski, L.T.


    With the help of technologies such as GPS tracks, GIS and open data is now possible to study people travel behaviour in a new way. Nowadays, large datasets can be easily handled thanks to databases and better visualized using GIS. Moreover, the availability of GPS data, open data and VGI makes


    Directory of Open Access Journals (Sweden)

    V. M. Rukhlinskiy


    Full Text Available This article considers the problem of assessment of data authenticity related to reliability of the flight data obtained in processing the information of portable GPS receivers’ during air accident investigations, which are characterized by the lack of standard flight data recording systems. Appropriate recommendations the improvement improving of the newly developed GPS receivers have been developed and implemented.

  20. Measurement of stride parameters using a wearable GPS and inertial measurement unit. (United States)

    Tan, Huiling; Wilson, Alan M; Lowe, John


    Both GPS and inertial measurement units (IMUs) have been extensively used in biomechanical studies. Expensive high accuracy GPS units can provide information about intrastride speed and position, but their application is limited by their size and cost. Single and double integration of acceleration from IMU provides information about short-term fluctuations in speed and position, but suffers from integration error over a longer period of time. The integration of GPS and IMU has been widely used in large and expensive units designed for survey and vehicle navigation. Here we propose a data fusion scheme, which is a Kalman filter based complementary filter and enhances the frequency response of the GPS and IMU used alone. We also report the design of a small (28 g) low cost GPS/IMU unit. Its accuracy after post-processing with the proposed data fusion scheme for determining average speed and intrastride variation was compared to a traditional high cost survey GPS. The low cost unit achieved an accuracy of 0.15 ms(-1) (s.d.) for horizontal speed in cycling and human running across a speed range of 3-10 ms(-1). The stride frequency and vertical displacement calculated based on measurements from the low cost GPS/IMU units had an s.d. of 0.08 Hz and 0.02 m respectively, compared to measurements from high performance OEM4 GPS units.

  1. The use of GPS horizontals for loading studies, with applications to northern California and southeast Greenland

    NARCIS (Netherlands)

    Wahr, J.; Khan, S.A.; van Dam, T.; Liu, Lin; van Angelen, J.H.|info:eu-repo/dai/nl/325922470; van den Broeke, M.R.|info:eu-repo/dai/nl/073765643; Meertens, C.M.


    We describe how GPS measurements of horizontal crustal motion can be used to augment vertical crustal motion measurements, to improve and extend GPS studies of surface loading. We show that the ratio of the vertical displacement to the horizontal displacement, combined with the direction of the

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

    DEFF Research Database (Denmark)

    Xu, G.C.; Knudsen, Per


    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 posit...

  3. Error detection in GPS observations by means of Multi-process models

    DEFF Research Database (Denmark)

    Thomsen, Henrik F.


    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...

  4. Continuous CWB GPS Array in Taiwan and Applications to Monitoring Seismic Activity

    Directory of Open Access Journals (Sweden)

    Tzay-Chyn Shin


    Full Text Available GPS observations have revealed important information for studying active tectonics and plate motion and are a useful tool for monitoring crustal deformation. The CWB continuous GPS array consists of approximately 150 stations with dense spatial coverage throughout Taiwan and can be used not only to monitor crustal deformation and seismic activity, but also to analyze the earthquake precursors in Taiwan.

  5. PosQ : Unsupervised Fingerprinting and Visualization of GPS Positioning Quality

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Weckemann, Kay


    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...

  6. Variation in diagnosis and management of common foot problems by GPs

    NARCIS (Netherlands)

    Gorter, K; de Melker, R; Kuyvenhoven, M; de Poel, S.


    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

  7. 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.


    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

  8. Evaluation of RTK-GPS and Total Station for applications in land ...

    Indian Academy of Sciences (India)

    The focus of this paper is on evaluating the dynamic accuracy of RTK-GPS and TS system in surveying land for agricultural engineering design practices. This goal was achieved through following specific objectives: • Evaluating the accuracy of data obtained through surveys where RTK-GPS and TS systems were used.

  9. Initiation of GPS-Acoustics Measurements on the Continental Slope of the Cascadia Subduction Zone (United States)

    Chadwell, C. D.


    Land-based GPS measurements suggest the megathrust is locked offshore along the Cascadia Subduction Zone. However, land-based data alone lack geometric resolution to constrain the how the slip is distributed. GPS-Acoustic measurements can provide these constraints, but using traditional GPS-Acoustic approaches employing a ship is costly. Wave Gliders, a wave- and solar-powered, remotely-piloted sea surface platform, provide a low cost method for collecting GPS-A data. We have adapted GPS-Acoustic technology to the Wave Glider. In July 2016, the GPS-A Wave Glider was launched on month-long mission to two sites on the continental slope of the Cascadia Subduction Zone. One site is approximately 45 NM offshore central Oregon and the other approximately 50 NM offshore central Washington State. We will report on initial results of the GPS-A data collection and operational experiences of the mission. Wave Glider based GPS-A measurement have the potential to significantly increase the number and frequency of measurements of strain accumulation in Cascadia Subduction Zone and elsewhere.

  10. 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. (United States)

    Verger, Pierre; Rolland, Sophie; Paraponaris, Alain; Bouvenot, Julien; Ventelou, Bruno


    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.

  11. Deformation of Northwestern South America from GPS Geodesy (United States)

    Mora-Paez, H.; La Femina, P. C.; Mothes, P. A.; Ruiz, A. G.; Fernandes, R. M.


    The North Andes block (NAB) is a hypothesized tectonic block that migrates (escapes) north-northeast relative to a stable South American reference frame. The motion of this block is thought-to-be derived by the collision of the Carnegie Ridge in southern Ecuador and/or by oblique convergence and high degrees of interplate coupling north of the ridge (i.e., strain partitioning). At the latitude of Ecuador, the NAB is defined by transpressional deformation accommodating east-northeastward motion along its boundary with South America. In southern to central Colombia, the NAB is dissected by several mapped and prominent regional shear zones. At these latitudes the NAB may be bound to the west by the Choco block and the transpressional Atrato-Uraba fault system and to the east by the Guayaquil-Algeciras fault system. And in northern Colombia the Caribbean - South America plate boundary is defined by the NAB and proposed Maracaibo and Guajira blocks. We investigate the deformation of northwestern South America, including the kinematics of NAB utilizing a new velocity field based on continuous GPS and existing episodic GPS data in Ecuador, Colombia, Venezuela and Panama. We reference these new velocities to a newly estimated Euler vector for the South America plate based on inversion of cGPS data from stations east of the Andes. The new velocity field and published earthquake slip vectors are inverted to solve for the Euler vectors of the NAB, Choco, Panama, Maracaibo and Guajira blocks and interseismic elastic strain accumulation (interseismic coupling) on block-bounding faults using a block modeling approach. We test a suite of block models to investigate the tectonic nature of the NAB along strike and the style of faulting in the upper plate accommodating block motion. Through the estimation of elastic strain accumulation on all block-bounding faults, we improve the understanding of interseismic coupling along a convergent margin capable of producing M>8 earthquakes

  12. Sporadic E Morphology from GPS-CHAMP Radio Occultation (United States)

    Wu, Dong L.; Ao, Chi O.; Hajj, George A.; de la Torre Juarez, Manuel; Mannucci, Anthony J.


    The scintillations of phase and amplitude in terms of signal-to-noise ratio (SNR) of the GPS radio occultation signal are caused by thin ionization layers. These thin irregular electron density layers in the E region ionosphere are often called sporadic E (Es). For a monthly retrieval of Es morphology we use the variances of the phase and SNR fluctuations of worldwide 6000 GPS/CHAMP occultations in the E region. The Es climatology is studied globally with the SNR and phase variances in terms of monthly zonal means, seasonal maps, and diurnal and long-term variations. The zonal mean variances reveal strong, extended Es activities at summertime midlatitudes but weak, confined activities in wintertime high latitudes, peaking at 105 km. Global maps at 105-km altitude show clear dependence of Es activities on the geomagnetic dip angle, where the summertime midlatitude Es occurs mostly at dip angles of 30 deg. - 60 deg. and the wintertime high-latitude enhancement occurs mostly at dip angles greater than 80 deg. The midlatitude Es variances exhibit a strong semidiurnal variation with peak hours near 0800 1000 and 2000 local solar time, respectively. The peak hours are delayed slightly with decreasing height, suggesting influences from the semidiurnal tide. To provide more insights on the observed SNR and phase variances, we model radio wave propagation for the CHAMP observing geometry under several perturbed cases in the E region ionosphere. The model simulations indicate that the SNR variance has the maximum response to Es perturbations at vertical wavelengths of 1.2 km, whereas the phase response maximizes at 2 km (for the 1-s variance analysis). The characteristic scale depends little on the truncation time used in the SNR variance analysis, but it increases with the truncation time for the phase variances. Initial studies show that reasonable global Es morphology can be produced on a monthly and seasonal basis with the CHAMP one-antenna occultations. Better results

  13. Potential GPS user architecture for the NASA Space Station based on Landsat 4/5 experience (United States)

    Korenstein, David A.


    A Landsat 4/5 GPS system is described which uses an inertial reference attitude control system and precision real-time ephemeris generation to achieve precision earth pointing. The system has application to the validation of the use of GPS for the low earth orbit navigation of the Space Station. The present system consists of a receiver/processor assembly (R/PA), an L-band GPS antenna, a precision oscillator, and the Landsat computer. The R/PA is integrated with a GPS receiver which selects, acquires, tracks, times, and decodes navigation signals from GPS satellites in order to derive ephemerides. Ephemeris estimates were found to be accurate to better than 50 meters.

  14. Real-time GPS Networks on Active Convergent Margins, Updates From Cascadia and Elsewhere (United States)

    Austin, K.; Enders, M.; Feaux, K.; Mattioli, G.; Mencin, D.; Meertens, C. M.; Walls, C. P.; Borsa, A. A.


    The EarthScope Plate Boundary Observatory (PBO), through a NSF-ARRA supplement, has enhanced geophysical infrastructure in in the Pacific Northwest by upgrading 232 Cascadia GPS stations to high-rate (1 Hz), low-latency (Unimak Island is streaming real-time data through the PBO data acquisition system, and recent upgrades in communications have opened the possibility of streaming additional sites on Augustine volcano. In addition, the expansion of cellular networks in Alaska is opening the possibilities of adding other stations. In summary, UNAVCO, as part of PBO, now operates nearly 350 high-rate real-time GPS (RT-GPS) stations along the western coast of North America and Alaska. The RT-GPS sites within PBO are monitored and managed using Trimble's VRS3Net software. UNAVCO staff is working closely with the UNAVCO community to develop data standards, protocols, and a science plan for the use of real-time GPS data.

  15. The Accidental Tide Gauge: A GPS Reflection Case Study from Kachemak Bay, Alaska (United States)

    Larson, Kristine M.; Ray, Richard D.; Nievinski, Felipe G..; Freymueller, Jeffrey T.


    For the last decade, it has been known that reflected GPS signals observed with specialized instruments could be used to measure sea level. In this letter, data from an existing geodeticquality GPS site near Kachemak Bay, Alaska, are analyzed for a one-year time period. Daily sea-level variations are more than 7 m. Tidal coefficients have been estimated and compared with coefficients estimated from records from a traditional tide gauge at Seldovia Harbor, approximately 30 km away. The GPS and Seldovia estimates of M(sub 2) and S(sub 2) coefficients agree to better than 2%; much of this residual can be attributed to true differences in the tide over 30 km as it propagates up Kachemak Bay. For daily mean sea levels the agreement is 2.3 cm. Because a standard geodetic GPS receiver/antenna is used, this GPS instrument can measure long-term sea-level changes in a stable terrestrial reference frame.

  16. Joint IRIS/UNAVCO/NASA Remote Seismic/GPS/VSAT Installations (United States)

    Ruud, O.; Stowers, D.; Butler, R.


    The UNAVCO Boulder Facility on behalf of NASA is collaborating with The Incorporated Research Institutions for Seismology (IRIS) on remote broadband seismic and GPS installations in support of the Global GPS Network (GGN) and the Global Seismographic Network (GSN). Seismic and GPS instruments share VSAT communications, power, facilities, maintenance, and site security. Collaborative sites include Mbarara Uganda, Franceville Gabon, Galapagos Islands, and Easter Island. High quality seismic and GPS data are now flowing to the GGN and GSN data collection centers. Future opportunities for collaboration include 16 collocated seismic and GPS installations as part of the NSN/GSN component of EarthScope. This poster will highlight past collaborative efforts, technology achievements, and identify new opportunities.

  17. A New Algorithm of Compensation of the Time Interval Error GPS-Based Measurements

    Directory of Open Access Journals (Sweden)

    Jonny Paul ZAVALA DE PAZ


    Full Text Available In this paper we present a new algorithm of compensation of the time interval error (TIE applying an unbiased p-step predictive finite impulse response (FIR filter at the signal of the receiver Global Positioning System (GPS-based measurements. The practical use of the system GPS involves various inherent problems of the signal. Two of the most important problems are the TIE and the instantaneous loss of the signal of the GPS by a small interval of time, called "holdover". The error holdover is a problem that at present does not possess solution and the systems that present this type of error produce lines of erroneous synchronization in the signal of the GPS. Basic holdover algorithms are discussed along with their most critical properties. Efficiency of the predictive filter in holdover is demonstrated in applications to GPS-based measurements of the TIE.

  18. Operational aspects of CASA UNO '88-The first large scale international GPS geodetic network (United States)

    Neilan, Ruth E.; Dixon, T. H.; Meehan, Thomas K.; Melbourne, William G.; Scheid, John A.; Kellogg, J. N.; Stowell, J. L.


    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.

  19. Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS) (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.


    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,

  20. Comparison of Four Different Methods for Agricultural Positioning Using GPS and IMU

    Directory of Open Access Journals (Sweden)

    H Goli


    Full Text Available In this research, four different positioning methods were compared in order to evaluate their accuracy, using a remotely controlled robot on a specific route. These methods included: using a single GPS module, combining the data from three GPS modules, using an Inertial Measurement Unit (IMU, and GPS/IMU data fusion. The comparison of these four methods showed that GPS/IMU data fusion along with a Kalman filter was the most precise method, having a root mean square error of 23.4cm. Integrating the data acquired simultaneously from three GPS modules with fixed and equally spaced position and far enough from each other, had a root mean square error of 31.3cm was the second most precise method. . Also analysis of the IMU data showed that due to cumulative errors, it was not a suitable method using a single IMU for positioning.

  1. Simulation and Performance Evaluations of the New GPS L5 and L1 Signals

    Directory of Open Access Journals (Sweden)

    Tahir Saleem


    Full Text Available The Global Positioning System (GPS signals are used for navigation and positioning purposes by a diverse set of users. As a part of GPS modernization effort L5 has been recently introduced for better accuracy and availability service. This paper intends to study and simulate the GPS L1/L5 signal in order to fulfill the following two objectives. The first aim is to point out some important features/differences between current L1 (whose characteristics have been fairly known and documented and new L5 GPS signal for performance evaluation purpose. The second aim is to facilitate receiver development, which will be designed and assembled later for the actual acquisition of GPS data. Simulation has been carried out for evaluation of correlation properties and link budgeting for both L1 and L5 signals. The necessary programming is performed in Matlab.

  2. Monitoring mobility in older adults using global positioning system (GPS) watches and accelerometers: a feasibility study. (United States)

    Webber, Sandra C; Porter, Michelle M


    This exploratory study examined the feasibility of using Garmin global positioning system (GPS) watches and ActiGraph accelerometers to monitor walking and other aspects of community mobility in older adults. After accuracy at slow walking speeds was initially determined, 20 older adults (74.4 +/- 4.2 yr) wore the devices for 1 day. Steps, distances, and speeds (on foot and in vehicle) were determined. GPS data acquisition varied from 43 min to over 12 hr, with 55% of participants having more than 8 hr between initial and final data-collection points. When GPS data were acquired without interruptions, detailed mobility information was obtained regarding the timing, distances covered, and speeds reached during trips away from home. Although GPS and accelerometry technology offer promise for monitoring community mobility patterns, new GPS solutions are required that allow for data collection over an extended period of time between indoor and outdoor environments.

  3. A study of antibiotic prescribing: the experience of Lithuanian and Russian GPs

    DEFF Research Database (Denmark)

    Jaruseviciene, Line; Bjerrum, Lars


    Background. Globally, general practitioners (GPs) write more than 90% of all antibiotic prescriptions. This study examines the experiences of Lithuanian and Russian GPs in antibiotic prescription for upper respiratory tract infections, including their perceptions of when it is not indicated clini...... to ensure correct antibiotic use. Further, GPs should be supported in enhancing their communication skills about antibiotic use with their patients and encouraged to implement a shared decision-making model in their practices.......Background. Globally, general practitioners (GPs) write more than 90% of all antibiotic prescriptions. This study examines the experiences of Lithuanian and Russian GPs in antibiotic prescription for upper respiratory tract infections, including their perceptions of when it is not indicated...

  4. Differences in prescribing between GPs: impact of the cooperation with pharmacists and impact of visits from pharmaceutical industry representatives.

    NARCIS (Netherlands)

    Muijrers, P.E.; Grol, R.P.T.M.; Sijbrandij, J.; Janknegt, R.; Knottnerus, J.A.


    BACKGROUND: Community pharmacists, pharmaceutical industry and differences in prescribing between GPs. OBJECTIVE: To explore the role of the pharmacists and pharmaceutical industry representatives. METHODS: A cross-sectional survey was undertaken of 1434 GPs in The Netherlands in 2001. Prescribing

  5. Investigation on food sanitation controlling technologies; Shokuhin eisei kanri gijutsu ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Y. [Hokkaido Electric Power Co. Inc., Sapporo (Japan); Nishioka, J.


    Investigation has been made on the current status of food sanitation controlling technologies. Eighty percent of food poisoning is caused by bacte such as Salmonera, enteritis vibrio, staphylococcus, and pathogenic colibacillus. Putrefaction as the cause for food poisoning occurs from proliferation of different microorganisms. Heating sterilization is the main method being performed, but non-heating method may include sterilization by flash and high voltage pulse discharge in addition to ultra-high pressure and ultraviolet ray sterilization. As a result of the questionnaire survey, what is extracted as the problems in the food sanitation controlling technologies is to establish a rinsing and sterilizing method with large sterilization effect, an effective sterilizing method and thawing of processed marine products, and a cooling method in food processing. Increasingly demanded for the future is to develop a foodstuff sanitation control system using as the core the hazard analysis critical control point (HACCP, a quality control program developed by the U.S. NASA to ensure safety in manufacturing space food), and micro-organism control and sterilizing technologies to support the above system. The flash pulse and high-voltage pulse sterilizing technologies as the non-heating sterilizing technology are more effective than the conventional heating sterilization methods also from the aspect of quality retention after sterilization. More active development thereof is desired. (NEDO)

  6. Foods hygiene management according to HACCP.; HACCP ni yoru shokuhin eisei kanri

    Energy Technology Data Exchange (ETDEWEB)

    Seki, T. [Niigata Enginering Co., Ltd., Tokyo (Japan)


    New foods hygiene management system HACCP(Hazard Analysis and Critical Control Point) was explained, which prevents food poisoning. Followings are described; (1) Outline of HACCP, (2) History of HAPPC, (3) Process to perform HACCP, (4) Infrastructure for HACCP, (5) How to promote HACCP, (6) Certification system in Japan. HACCP secures the safety in foods hygiene by making rules of Critical Control Points (CCP) on foods hygiene and by administrating strictly their performance. Details of works, frequency and person in charge of the work and methods to confirm and record the work are prescribed in PP (Prerequisite Program) and SSOP (Sanitation Standard Operation Procedure). (NEDO)

  7. Power generation device of artificial satellite. Jinko eisei no hatsuden sochi

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Takashi.


    As the conventional artificial satellite lacks a power generation controlling ability, a separate power controller is required which reduces the weight efficiency. It is not easy to freely control the photovoltaic ability of a solar cell projected on a satellite without causing an external turbulent moment on the main satellite body. For solving this problem, in this invention, in case a power is generated by a solar cell panel installed on the satellite in a pair, a shielding film and its driving device are equipped wherein the shielding film is made freely windable along the light receiving surface of a pair of the soalr cell panels and mutually movable in the opposite directions. By this, the device requires no shunt circuit, thus improving the economy, and reducing the total weight of the satellite. 2 figs.

  8. Review of current GPS methodologies for producing accurate time series and their error sources (United States)

    He, Xiaoxing; Montillet, Jean-Philippe; Fernandes, Rui; Bos, Machiel; Yu, Kegen; Hua, Xianghong; Jiang, Weiping


    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

  9. Navigating the Return Trip from the Moon Using Earth-Based Ground Tracking and GPS (United States)

    Berry, Kevin; Carpenter, Russell; Moreau, Michael C.; Lee, Taesul; Holt, Gregg N.


    NASA s Constellation Program is planning a human return to the Moon late in the next decade. From a navigation perspective, one of the most critical phases of a lunar mission is the series of burns performed to leave lunar orbit, insert onto a trans-Earth trajectory, and target a precise re-entry corridor in the Earth s atmosphere. A study was conducted to examine sensitivity of the navigation performance during this phase of the mission to the type and availability of tracking data from Earth-based ground stations, and the sensitivity to key error sources. This study also investigated whether GPS measurements could be used to augment Earth-based tracking data, and how far from the Earth GPS measurements would be useful. The ability to track and utilize weak GPS signals transmitted across the limb of the Earth is highly dependent on the configuration and sensitivity of the GPS receiver being used. For this study three GPS configurations were considered: a "standard" GPS receiver with zero dB antenna gain, a "weak signal" GPS receiver with zero dB antenna gain, and a "weak signal" GPS receiver with an Earth-pointing direction antenna (providing 10 dB additional gain). The analysis indicates that with proper selection and configuration of the GPS receiver on the Orion spacecraft, GPS can potentially improve navigation performance during the critical final phases of flight prior to Earth atmospheric entry interface, and may reduce reliance on two-way range tracking from Earth-based ground stations.

  10. GPs' views on managing advanced chronic kidney disease in primary care: a qualitative study. (United States)

    Tonkin-Crine, Sarah; Santer, Miriam; Leydon, Geraldine M; Murtagh, Fliss E M; Farrington, Ken; Caskey, Fergus; Rayner, Hugh; Roderick, Paul


    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.

  11. Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver (United States)

    Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.


    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.

  12. GPS in dynamic monitoring of long-period structures (United States)

    Celebi, M.


    Global Positioning System (GPS) technology with high sampling rates (??? 10 samples per second) allows scientifically justified and economically feasible dynamic measurements of relative displacements of long-period structures-otherwise difficult to measure directly by other means, such as the most commonly used accelerometers that require post-processing including double integration. We describe an experiment whereby the displacement responses of a simulated tall building are measured clearly and accurately in real-time. Such measurements can be used to assess average drift ratios and changes in dynamic characteristics, and therefore can be used by engineers and building owners or managers to assess the building performance during extreme motions caused by earthquakes and strong winds. By establishing threshold displacements or drift ratios and identifying changing dynamic characteristics, procedures can be developed to use such information to secure public safety and/or take steps to improve the performance of the building. Published by Elsevier Science Ltd.

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

    DEFF Research Database (Denmark)

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

    , economically and logistically, and further enables eventual reproduction of similar empirical data. The DUS research project is related to the general research focus found within the Urban Design section at Institute of Architecture, Design and Media Technology (AD:MT), Aalborg University (AAU......Background and purpose The Aalborg Survey consists of four independent parts: a web, GPS and an interview based survey and a literature study, which together form a consistent investigation and research into use of urban space, and specifically into young people’s use of urban space: what young...... people do in urban spaces, where they are in the urban spaces and when the young people are in the urban spaces. The answers to these questions form the framework and enable further academic discussions and conclusions in relation to the overall research project Diverse Urban Spaces (DUS). The primary...

  14. Modeling of GPS tropospheric delay wet Neill mapping function (NMF) (United States)

    Sakidin, Hamzah; Ahmad, Asmala; Bugis, Ismadi


    The modeling of the GPS tropospheric delay mapping function should be revised by modifying or simplify its mathematical model. Some current mapping functions models are separated into hydrostatic and the wet part. The current tropospheric delay models use mapping functions in the form of continued fractions. This model is quite complex and need to be simplified. By using regression method, the wet mapping function models has been selected to be simplified. There are eleven operations for wet mapping function component of Neill Mapping Function (NMF), to be carried out before getting the mapping function scale factor. So, there is a need to simplify the mapping function models to allow faster calculation and also better understanding of the models.

  15. Nonlinear speed estimation of a GPS-free UAV (United States)

    Santosuosso, Giovanni L.; Benzemrane, Khadidja; Damm, Gilney


    In this article, the problem of robust state observer design for a class of unmanned aerial vehicles (UAVs) is addressed. A prototype four-rotors helicopter robot for indoors and outdoors applications is considered: the drone is not equipped with GPS related devices, so we describe a strategy to estimate its translational velocity vector based on acceleration, angles and angular speeds measurements only. Since the linearised system is non-observable at the equilibrium point, a nonlinear observability verification is performed for persistently exciting trajectories. A global exponential solution to this open problem is provided in the framework of adaptive observation theory when exact measurements are available. A modified observer is presented to enhance velocity estimation robustness in the realistic case of noisy measurements. The results are compared with a classical estimation strategy based on the extended Kalman filter to test the algorithm's performance.

  16. Railway automatic safety protection system based on GPS

    Directory of Open Access Journals (Sweden)

    Fu Hai Juan


    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.

  17. Discrete filtering techniques applied to sequential GPS range measurements (United States)

    Vangraas, Frank


    The basic navigation solution is described for position and velocity based on range and delta range (Doppler) measurements from NAVSTAR Global Positioning System satellites. The application of discrete filtering techniques is examined to reduce the white noise distortions on the sequential range measurements. A second order (position and velocity states) Kalman filter is implemented to obtain smoothed estimates of range by filtering the dynamics of the signal from each satellite separately. Test results using a simulated GPS receiver show a steady-state noise reduction, the input noise variance divided by the output noise variance, of a factor of four. Recommendations for further noise reduction based on higher order Kalman filters or additional delta range measurements are included.

  18. Preliminary results from the ASF/GPS ice classification algorithm (United States)

    Cunningham, G.; Kwok, R.; Holt, B.


    The European Space Agency Remote Sensing Satellite (ERS-1) satellite carried a C-band synthetic aperture radar (SAR) to study the earth's polar regions. The radar returns from sea ice can be used to infer properties of ice, including ice type. An algorithm has been developed for the Alaska SAR facility (ASF)/Geophysical Processor System (GPS) to infer ice type from the SAR observations over sea ice and open water. The algorithm utilizes look-up tables containing expected backscatter values from various ice types. An analysis has been made of two overlapping strips with 14 SAR images. The backscatter values of specific ice regions were sampled to study the backscatter characteristics of the ice in time and space. Results show both stability of the backscatter values in time and a good separation of multiyear and first-year ice signals, verifying the approach used in the classification algorithm.

  19. Handbook of satellite orbits from Kepler to GPS

    CERN Document Server

    Capderou, Michel


    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...

  20. Quarry monitoring using GPS measurements and UAV photogrammetry (United States)

    Nikolakopoulos, Konstantinos G.; Koukouvelas, Ioannis; Argyropoulos, NIkolaos; Megalooikonomou, Vasileios


    The objective of this work is to indicate a monitoring methodology in order to survey the present state of the quarry sites and their evolution in time, which are the basic data needed to implement an adequate land reclamation project. The land monitoring has been realised by UAV photogrammetry and GPS measurements supported by a Geographic Information System. A six-rotor aircraft with a total weight of 6 kg carrying two small cameras has been used. Very accurate digital airphotos have been used in order to create orthophotos mosaic and DSM from the quarry planes. DGPS measurements and the data captured from the UAV are combined in GIS and the results are presented in the current study.