WorldWideScience

Sample records for sub-daily gps positions

  1. Enhancement of sub-daily positioning solutions for surface deformation monitoring at Deception volcano (South Shetland Islands, Antarctica)

    Science.gov (United States)

    Prates, G.; Berrocoso, M.; Fernández-Ros, A.; García, A.

    2013-02-01

    Deception Island is one of the most visited places in Antarctica. There are biological, geological, and archeological features that are major attractions within Port Foster, its horse shoe-shaped natural inner bay, and two scientific bases that are occupied during austral summers. Deception Island is an active volcano, however, and needs to be monitored in order to reduce risk to people on the island. Surface deformation in response to fluid pressure is one of the main volcanic activities to observe. Automated data acquisition and processing using the global navigation satellite systems allow measurements of surface deformation in near real time. Nevertheless, the positioning repeatability in sub-daily solutions is affected by geophysical influences such as ocean tidal loading, among others. Such periodic influences must be accurately modeled to achieve similar repeatability as daily solutions that average them. However, a single solution each 24 h will average out the deformation suffered during that period, and the position update waiting time can be a limitation for near real-time purposes. Throughout the last five austral summer campaigns in Deception, using simultaneous wireless communications between benchmarks, a processing strategy was developed to achieve millimeter-level half-hourly positioning solutions that have similar repeatability as those given by 24-h solutions. For these half-hourly solutions, a tidal analysis was performed to assess any mismodeling of ocean tide loading, and a discrete Kalman filter was designed and implemented to enhance the sub-daily positioning repeatability. With these solutions, the volcano-dynamic activity resulting in localized surface deformation for the last five austral summer campaigns is addressed. Although based on only three carefully located benchmarks, it is shown that Deception has been shortening and subsiding during these last 4 years. The method's accuracy in baselines up to a few hundred kilometers assures

  2. GPS Position Time Series @ JPL

    Science.gov (United States)

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

    2013-01-01

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

  3. UAV ONBOARD GPS IN POSITIONING DETERMINATION

    Directory of Open Access Journals (Sweden)

    K. N. Tahar

    2016-06-01

    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.

  4. Global Positioning System III (GPS III)

    Science.gov (United States)

    2015-12-01

    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

  5. Efficient GPS Position Determination Algorithms

    Science.gov (United States)

    2007-06-01

    Algorithm Let the reference receiver, m, have a known position represented as (xm, ym, zm) and the reported ith satellite position (via ephemeris data) be...vr is given as the velocity difference uvv &−=r (1-22) where v is the (known) velocity of the satellite and u& is the velocity of the user to be...this research and in our previous work reported in [15] and [16], an over-determined system is treated, making use of all-in-view (n ≥ 5) satellites as

  6. Indoor Positioning Using GPS Revisited

    DEFF Research Database (Denmark)

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

    2010-01-01

    availability is good in many buildings with standard material walls and roofs. The measured root mean squared 2D positioning error was below five meters in wooden buildings and below ten meters in most of the investigated brick and concrete buildings. Lower accuracies, where observed, can be linked to either...... within a given building is dependent on local properties like close-by building elements and materials, number of walls, number of overlaying stories and surrounding buildings....

  7. GPS Software Packages Deliver Positioning Solutions

    Science.gov (United States)

    2010-01-01

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

  8. Location - Global Positioning System (GPS) Photos

    Data.gov (United States)

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

  9. Case: The Global Positioning System (GPS)

    Science.gov (United States)

    2014-05-01

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

  10. Global Positioning System (GPS) Energetic Particle Data

    Data.gov (United States)

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

  11. Global Positioning Systems Directorate: GPS Update

    Science.gov (United States)

    2015-04-29

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

    Science.gov (United States)

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

    2014-01-01

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

  13. Separating Station-Dependent from Regionally-Coherent GPS Draconitics in Station Positions

    Science.gov (United States)

    Santamaría-Gómez, A.; Rebischung, P.; Ray, J.

    2016-12-01

    Spurious periodic oscillations of the station positions coincident with harmonics of the GPS draconitic year (about 351.2 d) are mostly coherent up to at least continental scales and are thought to be mainly related to corresponding effects in the GPS orbits. Possible sources could be deficiencies in the available models for sub-daily variations of the Earth orientation or solar radiation-induced satellite accelerations. Multipath near the ground antennas may also propagate into the draconitic harmonics in station positions due to the ground path repeat period being about four minutes shorter than the typical 24-hr data sampling interval. Separating such contributions might enable future mitigation strategies. However, detection and quantification of the multipath contribution is challenging as it depends on the local environment of each ground antenna, i.e., it is not spatially homogeneous and it can also vary in time. We analyzed the draconitic harmonics in station positions from the IGS second reprocessing campaign. Differences in the draconitics among eight contributing Analysis Centers were analyzed and deemed not statistically significant. The IGS combined time series were then used to assess station-dependent draconitics by differencing station pairs at different separation bins up to 2000 km. Differences in harmonic amplitude and phase were considered.

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

    Science.gov (United States)

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

    2015-04-29

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

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

    DEFF Research Database (Denmark)

    He, Zhe; Petovello, Mark; Pei, Ling

    2017-01-01

    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...

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

    Science.gov (United States)

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

    2017-02-01

    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.

  17. GPS AND GLONASS COMBINED STATIC PRECISE POINT POSITIONING (PPP

    Directory of Open Access Journals (Sweden)

    D. Pandey

    2016-06-01

    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%.

  18. GPS and Glonass Combined Static Precise Point Positioning (ppp)

    Science.gov (United States)

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

    2016-06-01

    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%.

  19. GPS

    African Journals Online (AJOL)

    spamer

    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.

  20. Geomagnetic Storm Impact On GPS Code Positioning

    Science.gov (United States)

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

    2017-04-01

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

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

    Directory of Open Access Journals (Sweden)

    WU Dongdong

    2016-02-01

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

  2. The NAVSTAR GPS (Global Positioning System) System

    Science.gov (United States)

    1988-09-01

    fixes" by combining the known positions of the heavenly bodies with on-board position measurements made with an instrument called an " astrolabe ". The...18th century, the sextant , compass, and star and sun tables were integrated with the clock to imp.ove navigatiu performance significantly. Later, a

  3. A New Indoor Positioning System Architecture Using GPS Signals

    Directory of Open Access Journals (Sweden)

    Rui Xu

    2015-04-01

    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.

  4. Lane Determination with GPS Precise Point Positioning

    NARCIS (Netherlands)

    Knoop, V.L.; de Bakker, P.F.; Tiberius, C.C.J.M.; van Arem, B.

    2017-01-01

    Modern intelligent transport solutions can achieve an improvement of traffic flow on motorways. With lane-specific measurements and lane-specific control, more measures are possible. Single frequency precise point positioning (PPP) is a newly developed and affordable technique to achieve an

  5. 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 ...

  6. GPS (Global Positioning System) Data Link for Test and Training

    Science.gov (United States)

    1982-09-01

    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

  7. IMU/GPS System Provides Position and Attitude Data

    Science.gov (United States)

    Lin, Ching Fang

    2006-01-01

    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.

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

    OpenAIRE

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

    2006-01-01

    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.

  9. Noise in GPS position time series from Taiwan

    Science.gov (United States)

    Rau, Ruey-Juin; Hung, Huang-Kai

    2014-05-01

    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

  10. Combined Positioning Algorithm and Accuracy Analysis for BD2/GPS Positioning System

    National Research Council Canada - National Science Library

    Chun Liu; Chao Wang; Jiaoyan Liang

    To restrain the error sources, namely ionospheric delay and tropospheric delay, in the solution method of BD2/GPS combined positioning system, we introduce the Klobuchar model and Hopfield model to correct...

  11. 76 FR 67019 - Eighty-Seventh: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2011-10-28

    ... 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...

  12. 77 FR 56254 - 89th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Science.gov (United States)

    2012-09-12

    ... 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...

  13. 77 FR 12106 - 88th Meeting: RTCA Special Committee 159, Global Positioning System (GPS)

    Science.gov (United States)

    2012-02-28

    ... 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...

  14. 78 FR 13396 - 90th Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Science.gov (United States)

    2013-02-27

    ... 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...

  15. 76 FR 27744 - Eighty-Fifth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2011-05-12

    ... 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...

  16. 75 FR 61818 - Eighty-Third Meeting: RTCA Special Committee 159: Global Positioning System (GPS).

    Science.gov (United States)

    2010-10-06

    ... 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...

  17. 76 FR 33022 - Eighty-Sixth Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2011-06-07

    ... 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...

  18. 75 FR 2581 - Eighty-First Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2010-01-15

    ... 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...

  19. 76 FR 50808 - Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS)

    Science.gov (United States)

    2011-08-16

    ... 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...

  20. 75 FR 28318 - Eighty-Second Meeting: RTCA Special Committee 159: Global Positioning System (GPS)

    Science.gov (United States)

    2010-05-20

    ... 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...

  1. Convergence Time and Positioning Accuracy Comparison between BDS and GPS Precise Point Positioning

    Directory of Open Access Journals (Sweden)

    ZHANG Xiaohong

    2015-03-01

    Full Text Available BDS/GPS data from MGEX were processed by TriP 2.0 software developed at Wuhan University. Both static and kinematic float PPP are tested by adopting precise satellite orbits and clocks provided by Research Center of GNSS, Wuhan University. The results show that the convergence time of BDS static PPP is about 80min while kinematic PPP is about 100min. For 3h observations, static positioning accuracy of 5 cm and kinematic positioning accuracy of 8 cm in horizontal, about 12 cm in vertical can be achieved. Similar to GPS PPP, precision in east component is worse than north. At present, BDS PPP needs longer convergence time than GPS PPP to reach an absolute positioning accuracy of cm~dm due to the lack of global tracking stations and the limited accuracy of orbit and clock products.

  2. GPS and odometer data fusion for outdoor robots continuous positioning

    Science.gov (United States)

    Pozo-Ruz, Ana; Garcia-Perez, Lia; Garcia-Alegre, Maria C.; Guinea, Domingo; Ribeiro, Angela; Sandoval, Francisco

    2002-02-01

    Present work describes an approximation to obtain the best estimation of the position of the outdoor robot ROJO, a low cost lawnmower to perform unmanned precision agriculture task such are the spraying of pesticides in horticulture. For continuous location of ROJO, two redundant sensors have been installed onboard: a DGPS submetric precision model and an odometric system. DGPS system will allow an absolute positioning of the vehicle in the field, but GPS failures in the reception of the signals due to obstacles and electrical and meteorological disturbance, lead us to the integration of the odometric system. Thus, a robust odometer based upon magnetic strip sensors has been designed and integrated in the vehicle. These sensors continuosly deliver the position of the vehicle relative to its initial position, complementing the DGPS blindness periods. They give an approximated location of the vehicle in the field that can be in turn conveniently updated and corrected by the DGPS. Thus, to provided the best estimation, a fusion algorithm has been proposed and proved, wherein the best estimation is calculated as the maximum value of the join probability function obtained from both position estimation of the onboard sensors. Some results are presented to show the performance of the proposed sensor fusion technique.

  3. PosQ : Unsupervised Fingerprinting and Visualization of GPS Positioning Quality

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Weckemann, Kay

    2010-01-01

    GPS positioning does not provide pervasive coverage and the accuracy depends on the local environment. When deploying and managing position-based applications it is important to know when to depend on GPS and when to deploy supplementary means of positioning, such as local or inertial positioning...

  4. PDOP values for simulated GPS/Galileo positioning

    DEFF Research Database (Denmark)

    Cederholm, Jens Peter

    2005-01-01

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

  5. 78 FR 57672 - 91st Meeting: RTCA Special Committee 159, Global Positioning Systems (GPS)

    Science.gov (United States)

    2013-09-19

    .... 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...

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

    DEFF Research Database (Denmark)

    Xu, G.C.; Knudsen, Per

    2000-01-01

    A detailed Study of the Earth tide effects on the GPS kinematic/static positioning is presented in this paper by using theoretical Earth tide computation and practical GPS data processing. Tidal effects could reach up to 30 cm in Denmark and Greenland depending on the measuring time and the posit...

  7. Kinematic positioning of LEO and GPS satellites and IGS stations on the ground

    Science.gov (United States)

    Švehla, Dražen; Rothacher, Markus

    For the first time, we publish results with the kinematic positioning of the GPS satellites and make comparisons with the kinematic positioning of LEO satellites and IGS stations on the ground. We show that LEO point-positioning is possible by means of GPS satellite clocks estimated solely based on phase GPS measurements. In sequel, we introduce a fourth approach in precise orbit determination, which we call reduced-kinematic POD, where kinematic position differences in time are constrained to corresponding differences in a priori dynamic orbit.

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

    Science.gov (United States)

    Afifi, Akram; El-Rabbany, Ahmed

    2015-06-19

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

  9. Comparison of Four Different Methods for Agricultural Positioning Using GPS and IMU

    Directory of Open Access Journals (Sweden)

    H Goli

    2014-09-01

    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.

  10. Airborne Pseudolites in a Global Positioning System (GPS) Degraded Environment

    Science.gov (United States)

    2011-03-01

    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

  11. PosQ : Unsupervised Fingerprinting and Visualization of GPS Positioning Quality

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Weckemann, Kay

    2010-01-01

    . This paper proposes PosQ, a system for unsupervised fingerprinting and visualization of GPS positioning quality. PosQ provides quality maps to position-based applications and visual overlays to users and managers to reveal the positioning quality in a local environment. The system reveals the quality both...... as it changes over time, in 2D and 3D, and for each type of GPS receiver. Our evaluation provides evidence that the collected quality maps are accurate, that they remain informative over time, that they capture the differences among GPS receivers, and that they can be efficiently collected by participating...

  12. PosQ: Unsupervised Fingerprinting and Visualization of GPS Positioning Quality

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Weckemann, Kay

    . This paper proposes PosQ, a system for unsupervised fingerprinting and visualization of GPS positioning quality. PosQ provides quality maps to position-based applications and visual overlays to users and managers to reveal the positioning quality in a local environment. The system reveals the quality both...... as it changes over time, in 2D and 3D, and for each type of GPS receiver. Our evaluation provides evidence that the collected quality maps are accurate, that they remain informative over time, that they capture the differences among GPS receivers, and that they can be efficiently collected by participating...

  13. Uav Onboard Photogrammetry and GPS Positionning for Earthworks

    Science.gov (United States)

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

    2015-08-01

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

  14. Expected Position Error for an Onboard Satellite GPS Receiver

    Science.gov (United States)

    2015-03-01

    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

  15. Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based...

  16. IceBridge GPS/IMU L1B Primary Position and Attitude Solution, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge GPS/IMU L1B Primary Position and Attitude Solution (IPUTG1B) data set contains elevation, roll, pitch, heading, north-south acceleration,...

  17. IceBridge GPS/IMU L1B Primary Position and Attitude Solution

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge GPS/IMU L1B Primary Position and Attitude Solution (IPUTG1B) data set contains elevation, roll, pitch, heading, north-south acceleration,...

  18. Modular Software for Spacecraft Navigation Using the Global Positioning System (GPS)

    Science.gov (United States)

    Truong, S. H.; Hartman, K. R.; Weidow, D. A.; Berry, D. L.; Oza, D. H.; Long, A. C.; Joyce, E.; Steger, W. L.

    1996-01-01

    The Goddard Space Flight Center Flight Dynamics and Mission Operations Divisions have jointly investigated the feasibility of engineering modular Global Positioning SYSTEM (GPS) navigation software to support both real time flight and ground postprocessing configurations. The goals of this effort are to define standard GPS data interfaces and to engineer standard, reusable navigation software components that can be used to build a broad range of GPS navigation support applications. The paper discusses the GPS modular software (GMOD) system and operations concepts, major requirements, candidate software architecture, feasibility assessment and recommended software interface standards. In additon, ongoing efforts to broaden the scope of the initial study and to develop modular software to support autonomous navigation using GPS are addressed,

  19. Monitoring mobility in older adults using global positioning system (GPS) watches and accelerometers: a feasibility study.

    Science.gov (United States)

    Webber, Sandra C; Porter, Michelle M

    2009-10-01

    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.

  20. A Demonstration of GPS Landslide Monitoring Using Online Positioning User Service (OPUS)

    Science.gov (United States)

    Wang, G.

    2011-12-01

    Global Positioning System (GPS) technologies have been frequently applied to landslide study, both as a complement, and as an alternative to conventional surveying methods. However, most applications of GPS for landslide monitoring have been limited to the academic community for research purposes. High-accuracy GPS has not been widely equipped in geotechnical companies and used by technicians. The main issue that limits the applications of GPS in the practice of high-accuracy landslide monitoring is the complexity of GPS data processing. This study demonstrated an approach using the Online Positioning User Service (OPUS) (http://www.ngs.noaa.gov/OPUS) provided by the National Geodetic Survey (NGS) of National Oceanic and Atmospheric Administration (NOAA) to process GPS data and conduct long-term landslide monitoring in the Puerto Rico and Virgin Islands Region. Continuous GPS data collected at a creeping landslide site during two years were used to evaluate different scenarios for landslide surveying: continuous or campaign, long duration or short duration, morning or afternoon (different weather conditions). OPUS uses Continuously Operating Reference Station (CORS) managed by NGS (http://www.ngs.noaa.giv/CORS/) as references and user data as a rover to solve a position. There are 19 CORS permanent GPS stations in the Puerto Rico and Virgin Islands region. The dense GPS network provides a precise and reliable reference frame for subcentimeter-accuracy landslide monitoring in this region. Our criterion for the accuracy was the root-mean-square (RMS) of OPUS solutions over a 2-year period with respect to true landslide displacement time series overt the same period. The true landslide displacements were derived from a single-baseline (130 m) GPS processing by using 24-hour continuous data. If continuous GPS surveying is performed in the field, then OPUS static processing can provide 0.6 cm horizontal and 1.1 cm vertical precision with few outliers. If repeated

  1. Precise Positioning of Uavs - Dealing with Challenging Rtk-Gps Measurement Conditions during Automated Uav Flights

    Science.gov (United States)

    Zimmermann, F.; Eling, C.; Klingbeil, L.; Kuhlmann, H.

    2017-08-01

    For some years now, UAVs (unmanned aerial vehicles) are commonly used for different mobile mapping applications, such as in the fields of surveying, mining or archeology. To improve the efficiency of these applications an automation of the flight as well as the processing of the collected data is currently aimed at. One precondition for an automated mapping with UAVs is that the georeferencing is performed directly with cm-accuracies or better. Usually, a cm-accurate direct positioning of UAVs is based on an onboard multi-sensor system, which consists of an RTK-capable (real-time kinematic) GPS (global positioning system) receiver and additional sensors (e.g. inertial sensors). In this case, the absolute positioning accuracy essentially depends on the local GPS measurement conditions. Especially during mobile mapping applications in urban areas, these conditions can be very challenging, due to a satellite shadowing, non-line-of sight receptions, signal diffraction or multipath effects. In this paper, two straightforward and easy to implement strategies will be described and analyzed, which improve the direct positioning accuracies for UAV-based mapping and surveying applications under challenging GPS measurement conditions. Based on a 3D model of the surrounding buildings and vegetation in the area of interest, a GPS geometry map is determined, which can be integrated in the flight planning process, to avoid GPS challenging environments as far as possible. If these challenging environments cannot be avoided, the GPS positioning solution is improved by using obstruction adaptive elevation masks, to mitigate systematic GPS errors in the RTK-GPS positioning. Simulations and results of field tests demonstrate the profit of both strategies.

  2. Performance of Taiwan Ionospheric Model (TWIM) in Single-Frequency Differential GPS Positioning

    Science.gov (United States)

    Macalalad, Ernest; Chih Tsai, Lung; Wu, Joz; Liu, Chao Han

    2014-05-01

    Differential Global Positioning System (DGPS) is one of the common techniques using GPS positioning. One of its main advantages is the removal of clock biases of GPS satellites which greatly improves position accuracy. With this, only differential atmospheric (ionospheric and tropospheric) errors, receiver clock biases and measurement noise mainly remain and can be removed using various models. This study focuses on the differential ionospheric delay and the effect of its correction to DGPS positioning. Being the major source of error in GPS L1 pseudorange, this ionospheric delay is determined using a three-dimensional phenomenological ionospheric model called the TaiWan Ionospheric Model (TWIM). TWIM is derived from GPS radio occultation measurements of the Formosat3/COSMIC program. This error is removed from the pseudorange observations, which is then used to perform single-difference DGPS positioning. A network of 10 GPS receivers across Taiwan is used as both test and reference receivers in doing the differential positioning. The network has a maximum horizontal baseline of 400 km. It has been shown that TWIM can provide sub-meter positioning and can provide better positioning than other models such as Klobuchar and GIM. TWIM can also reduce the dependence of positioning accuracy to baseline length and solar flux for a 24-hour survey.

  3. GPS/Low-Cost IMU/Onboard Vehicle Sensors Integrated Land Vehicle Positioning System

    Directory of Open Access Journals (Sweden)

    Gao Jianchen

    2007-01-01

    Full Text Available This paper aims to develop a GPS, low-cost IMU, and onboard vehicle sensors integrated land vehicle positioning system at low cost and with high (cm level accuracy. Using a centralized Kalman filter, the integration strategies and algorithms are discussed. A mechanism is proposed for detecting and alleviating the violation of the lateral nonholonomic constraint on the wheel speed sensors that is widely used in previous research. With post-mission and real-time tests, the benefits gained from onboard vehicle sensors and the side slip detection and alleviation mechanism in terms of the horizontal positioning accuracy are analyzed. It is illustrated by all the tests that GPS plays a dominant role in determining the absolute positioning accuracy of the system when GPS is fully available. The integration of onboard vehicle sensors can improve the horizontal positioning accuracy during GPS outages. With respect to GPS and low-cost IMU integrated system, the percentage improvements from the wheel speed sensor are 90.4% for the open-sky test and 56.0% for suburban area real-time test. By integrating all sensors to detect and alleviate the violation of the lateral nonholonomic constraint, the percentage improvements over GPS and low-cost IMU integrated system can be enhanced to 92.6% for open-sky test and 65.1% for the real-time test in suburban area.

  4. Nominal and Real Accuracy of the GPS Position Indicated by Different Maritime Receivers in Different Modes

    Directory of Open Access Journals (Sweden)

    Jacek Januszewski

    2014-03-01

    Full Text Available Nowadays on the ship's bridge two or even more GPS receivers are installed. As in the major cases the coordinates of the position obtained from these receivers differ the following questions can be posed - what is the cause of this divergence, which receiver in the first must be taken into account etc. Based on information published in annual GPS and GNSS receiver survey it was estimated the percentage of GPS receivers designed for marine and/or navigation users. The measurements of GPS position based on the four different stationary GPS receivers were realized in the laboratory of Gdynia Maritime University in Poland in the summer 2012. The coordinates of the position of all these receivers were registered at the same time. The measurements in mode 3D were made for different input data, the same for all receivers. The distances between the individual unit's antenna were considered also. Next measurements in mode 3D also were realized on two ships in different European ports. Additional measurements were made in mode 2D with three receivers for different their's antenna heights. The results showed that the GPS position accuracy depends on the type of the receiver and its technical parameters particularly.

  5. BDS/GPS Dual Systems Positioning Based on the Modified SR-UKF Algorithm

    Directory of Open Access Journals (Sweden)

    JaeHyok Kong

    2016-05-01

    Full Text Available The Global Navigation Satellite System can provide all-day three-dimensional position and speed information. Currently, only using the single navigation system cannot satisfy the requirements of the system’s reliability and integrity. In order to improve the reliability and stability of the satellite navigation system, the positioning method by BDS and GPS navigation system is presented, the measurement model and the state model are described. Furthermore, the modified square-root Unscented Kalman Filter (SR-UKF algorithm is employed in BDS and GPS conditions, and analysis of single system/multi-system positioning has been carried out, respectively. The experimental results are compared with the traditional estimation results, which show that the proposed method can perform highly-precise positioning. Especially when the number of satellites is not adequate enough, the proposed method combine BDS and GPS systems to achieve a higher positioning precision.

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

    Directory of Open Access Journals (Sweden)

    Jong-Hwa Song

    2016-10-01

    Full Text Available The Global Positioning System (GPS is the most widely used navigation system in land vehicle applications. In urban areas, the GPS suffers from insufficient signal strength, multipath propagation and non-line-of-sight (NLOS errors, so it thus becomes difficult to obtain accurate and reliable position information. In this paper, an integration algorithm for multiple receivers is proposed to enhance the positioning performance of GPS for land vehicles in urban areas. The pseudoranges of multiple receivers are integrated based on a tightly coupled approach, and erroneous measurements are detected by testing the closeness of the pseudoranges. In order to fairly compare the pseudoranges, GPS errors and terms arising due to the differences between the positions of the receivers need to be compensated. The double-difference technique is used to eliminate GPS errors in the pseudoranges, and the geometrical distance is corrected by projecting the baseline vector between pairs of receivers. In order to test and analyze the proposed algorithm, an experiment involving live data was performed. The positioning performance of the algorithm was compared with that of the receiver autonomous integrity monitoring (RAIM-based integration algorithm for multiple receivers. The test results showed that the proposed algorithm yields more accurate position information in urban areas.

  7. Recursive Least Squares with Real Time Stochastic Modeling: Application to GPS Relative Positioning

    Science.gov (United States)

    Zangeneh-Nejad, F.; Amiri-Simkooei, A. R.; Sharifi, M. A.; Asgari, J.

    2017-09-01

    Geodetic data processing is usually performed by the least squares (LS) adjustment method. There are two different forms for the LS adjustment, namely the batch form and recursive form. The former is not an appropriate method for real time applications in which new observations are added to the system over time. For such cases, the recursive solution is more suitable than the batch form. The LS method is also implemented in GPS data processing via two different forms. The mathematical model including both functional and stochastic models should be properly defined for both forms of the LS method. Proper choice of the stochastic model plays an important role to achieve high-precision GPS positioning. The noise characteristics of the GPS observables have been already investigated using the least squares variance component estimation (LS-VCE) in a batch form by the authors. In this contribution, we introduce a recursive procedure that provides a proper stochastic modeling for the GPS observables using the LS-VCE. It is referred to as the recursive LS-VCE (RLS-VCE) method, which is applied to the geometry-based observation model (GBOM). In this method, the (co)variances parameters can be estimated recursively when the new group of observations is added. Therefore, it can easily be implemented in real time GPS data processing. The efficacy of the method is evaluated using a real GPS data set collected by the Trimble R7 receiver over a zero baseline. The results show that the proposed method has an appropriate performance so that the estimated (co)variance parameters of the GPS observables are consistent with the batch estimates. However, using the RLS-VCE method, one can estimate the (co)variance parameters of the GPS observables when a new observation group is added. This method can thus be introduced as a reliable method for application to the real time GPS data processing.

  8. Positioning Accuracy Analysis of GPS/BDS/GLONASS Network RTK Based on DREAMNET

    Directory of Open Access Journals (Sweden)

    YAO Yibin

    2016-09-01

    Full Text Available With BDS being continually providing service in the Asia-Pacific Region, GLONASS being fully operational with 24 satellites in orbit again and GPS modernization, multi-GNSS network RTK will become the development trend of network RTK in the future. The data of multi-GNSS will be process by data reserving, editing and managing system of network RTK (DREAMNET, which developed independently by this research group, to analyze and compare the positioning accuracy between different combinations of global navigation satellite system. According to the experiment, the positioning accuracy of GPS/BDS/GLONASS network RTK and GPS/BDS network RTK is highest, GPS and BDS only second. Besides, with the increasing of the cut-off elevation, the availability of single GPS network RTK significantly reduces. However with 40°cut-off elevations, positioning service with the accuracy of 0.005m in horizontal, 0.025m in vertical will be provided by GPS/BDS/GLONASS network RTK in 99.84% time of a day. Finally, the statistics of positioning accuracy for 15days show that the accuracy of 0.01m in horizontal, 0.025m in vertical could be reached in six situations, which including BDS and BDS/GLONASS network RTK. Besides, the accuracy of 0.006m in horizontal, 0.015m in vertical could be reached by GPS/BDS/GLONASS network RTK, proving that the positioning accuracy and stability of DREAMNET can meet the needs of surveying and mapping.

  9. 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

    2002-01-01

    .... 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...

  10. Time Study of Harvesting Equipment Using GPS-Derived Positional Data

    Science.gov (United States)

    Tim McDonald

    1999-01-01

    The objectives in this study were to develop and test a data analysis system for calculating machine productivity from GPS-derived positional information alone. A technique was used where positions were `filtered' initially to locate specific events that were independent of what actually traveled the path, then these events were combined using user-specified rules...

  11. Evaluation of GPS Standard Point Positioning with Various Ionospheric Error Mitigation Techniques

    Science.gov (United States)

    Panda, Sampad K.; Gedam, Shirish S.

    2016-12-01

    The present paper investigates accuracy of single and dual-frequency Global Positioning System (GPS) standard point positioning solutions employing different ionosphere error mitigation techniques. The total electron content (TEC) in the ionosphere is the prominent delay error source in GPS positioning, and its elimination is essential for obtaining a relatively precise positioning solution. The estimated delay error from different ionosphere models and maps, such as Klobuchar model, global ionosphere models, and vertical TEC maps are compared with the locally derived ionosphere error following the ion density and frequency dependence with delay error. Finally, the positional accuracy of the single and dual-frequency GPS point positioning solutions are probed through different ionospheric mitigation methods including exploitation of models, maps, and ionosphere-free linear combinations and removal of higher order ionospheric effects. The results suggest the superiority of global ionosphere maps for single-frequency solution, whereas for the dual-frequency measurement the ionosphere-free linear combination with prior removal of higher-order ionosphere effects from global ionosphere maps and geomagnetic reference fields resulted in improved positioning quality among the chosen mitigation techniques. Conspicuously, the susceptibility of height component to different ionospheric mitigation methods are demonstrated in this study which may assist the users in selecting appropriate technique for precise GPS positioning measurements.

  12. GPS/GLONASS Combined Precise Point Positioning with Receiver Clock Modeling.

    Science.gov (United States)

    Wang, Fuhong; Chen, Xinghan; Guo, Fei

    2015-06-30

    Research has demonstrated that receiver clock modeling can reduce the correlation coefficients among the parameters of receiver clock bias, station height and zenith tropospheric delay. This paper introduces the receiver clock modeling to GPS/GLONASS combined precise point positioning (PPP), aiming to better separate the receiver clock bias and station coordinates and therefore improve positioning accuracy. Firstly, the basic mathematic models including the GPS/GLONASS observation equations, stochastic model, and receiver clock model are briefly introduced. Then datasets from several IGS stations equipped with high-stability atomic clocks are used for kinematic PPP tests. To investigate the performance of PPP, including the positioning accuracy and convergence time, a week of (1-7 January 2014) GPS/GLONASS data retrieved from these IGS stations are processed with different schemes. The results indicate that the positioning accuracy as well as convergence time can benefit from the receiver clock modeling. This is particularly pronounced for the vertical component. Statistic RMSs show that the average improvement of three-dimensional positioning accuracy reaches up to 30%-40%. Sometimes, it even reaches over 60% for specific stations. Compared to the GPS-only PPP, solutions of the GPS/GLONASS combined PPP are much better no matter if the receiver clock offsets are modeled or not, indicating that the positioning accuracy and reliability are significantly improved with the additional GLONASS satellites in the case of insufficient number of GPS satellites or poor geometry conditions. In addition to the receiver clock modeling, the impacts of different inter-system timing bias (ISB) models are investigated. For the case of a sufficient number of satellites with fairly good geometry, the PPP performances are not seriously affected by the ISB model due to the low correlation between the ISB and the other parameters. However, the refinement of ISB model weakens the

  13. Demonstrating Tools and Results of a Measurement Campaign for Indoor GPS Positioning

    DEFF Research Database (Denmark)

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

    It has been considered a fact that GPS performs too poorly inside buildings to provide usable indoor positioning. We demo raw measurements and results from a measurement campaign which show that using state-of-the-art receivers GPS availability is good in many buildings with standard material walls...... and roofs: The root mean squared accuracy of the measured positions is below five meters in wooden buildings and below ten meters in most of the investigated brick and concrete buildings. Lower accuracies, where observed, can be linked to either low signal-to-noise ratios, multipath phenomena or bad...

  14. The use of Global Positioning System (GPS) tracking devices to ...

    African Journals Online (AJOL)

    The intermittent nature of Under-19 rugby union match play, as well as the unique roles and requirements of positional groups, were confirmed. ... of collisions experienced by players, can assist coaches with planning specific training programmes, as well as adequate recovery between training sessions and games.

  15. Creating a global sub-daily precipitation dataset

    Science.gov (United States)

    Lewis, Elizabeth; Blenkinsop, Stephen; Fowler, Hayley

    2017-04-01

    Extremes of precipitation can cause flooding and droughts which can lead to substantial damages to infrastructure and ecosystems and can result in loss of life. It is still uncertain how hydrological extremes will change with global warming as we do not fully understand the processes that cause extreme precipitation under current climate variability. The INTENSE project is using a novel and fully-integrated data-modelling approach to provide a step-change in our understanding of the nature and drivers of global precipitation extremes and change on societally relevant timescales, leading to improved high-resolution climate model representation of extreme rainfall processes. The INTENSE project is in conjunction with the World Climate Research Programme (WCRP)'s Grand Challenge on 'Understanding and Predicting Weather and Climate Extremes' and the Global Water and Energy Exchanges Project (GEWEX) Science questions. The first step towards achieving this is to construct a new global sub-daily precipitation dataset. Data collection is ongoing and already covers North America, Europe, Asia and Australasia. Comprehensive, open source quality control software is being developed to set a new standard for verifying sub-daily precipitation data and a set of global hydroclimatic indices will be produced based upon stakeholder recommendations. This will provide a unique global data resource on sub-daily precipitation whose derived indices, e.g. monthly/annual maxima, will be freely available to the wider scientific community.

  16. An effective approach to improving low-cost GPS positioning accuracy in real-time navigation.

    Science.gov (United States)

    Islam, Md Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4-10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy.

  17. An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation

    Directory of Open Access Journals (Sweden)

    Md. Rashedul Islam

    2014-01-01

    Full Text Available Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS. This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4–10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy.

  18. SDCLIREF - A sub-daily gridded reference dataset

    Science.gov (United States)

    Wood, Raul R.; Willkofer, Florian; Schmid, Franz-Josef; Trentini, Fabian; Komischke, Holger; Ludwig, Ralf

    2017-04-01

    Climate change is expected to impact the intensity and frequency of hydrometeorological extreme events. In order to adequately capture and analyze extreme rainfall events, in particular when assessing flood and flash flood situations, data is required at high spatial and sub-daily resolution which is often not available in sufficient density and over extended time periods. The ClimEx project (Climate Change and Hydrological Extreme Events) addresses the alteration of hydrological extreme events under climate change conditions. In order to differentiate between a clear climate change signal and the limits of natural variability, unique Single-Model Regional Climate Model Ensembles (CRCM5 driven by CanESM2, RCP8.5) were created for a European and North-American domain, each comprising 50 members of 150 years (1951-2100). In combination with the CORDEX-Database, this newly created ClimEx-Ensemble is a one-of-a-kind model dataset to analyze changes of sub-daily extreme events. For the purpose of bias-correcting the regional climate model ensembles as well as for the baseline calibration and validation of hydrological catchment models, a new sub-daily (3h) high-resolution (500m) gridded reference dataset (SDCLIREF) was created for a domain covering the Upper Danube and Main watersheds ( 100.000km2). As the sub-daily observations lack a continuous time series for the reference period 1980-2010, the need for a suitable method to bridge the gap of the discontinuous time series arouse. The Method of Fragments (Sharma and Srikanthan (2006); Westra et al. (2012)) was applied to transform daily observations to sub-daily rainfall events to extend the time series and densify the station network. Prior to applying the Method of Fragments and creating the gridded dataset using rigorous interpolation routines, data collection of observations, operated by several institutions in three countries (Germany, Austria, Switzerland), and the subsequent quality control of the observations

  19. Real Time Position Detection by Using GPS+GSM+GPRS and Arduino Mega Based Telit GL865

    OpenAIRE

    Baki Koyuncu; ZeynepÖzdemir

    2016-01-01

    A web application on a mobile platform is developed by using GPS, GSMand GPRSon an Arduino Mega board to determine the object positions in real time.The system receives the GPS position data and sends it to a distant server through a GSM channel by using GPRS and an Arduino Mega board. Position data is displayed on a Google map on the server or a mobile cell phone. U BloxLea is deployed as the GPS device, Telit GL865 is used as the combined GSM and GPRS devices. GPS data is received every 1 s...

  20. Advanced Transport Telematics Positioning Requirements: An Assessment of GPS Performance in Greater London

    Science.gov (United States)

    Ochieng, W. Y.; Shardlow, P. J.; Johnston, Gordon

    This paper presents the results of a study carried out in the Greater London area to assess and characterise the performance of the Global Positioning System (GPS) for vehicle positioning in urban areas. The performance assessment addresses, in varying levels of detail, the issues of service coverage, positioning accuracy, integrity and availability of service. The project was supported by Racal Survey Limited and is part of the wider research at Imperial College in the area of architectural design and testing of Advanced Transport Telematics (ATT) systems. The results highlight the shortcomings of GPS as the sole means for in-car navigation in urban areas and details the temporal and spatial considerations to be taken into account in the process of designing an integrated positioning system capable of meeting navigation requirements placed on ATT systems.

  1. Enhancing the accuracy of GPS point positioning by converting the single frequency data to dual frequency data

    Directory of Open Access Journals (Sweden)

    Aly M. El-naggar

    2011-09-01

    Full Text Available The global positioning system (GPS has been used to support a wide variety of applications, such as high-accuracy positioning and navigation. Differential GPS techniques can largely eliminate common-mode errors between the reference and the rover GPS stations resulting from ionospheric and tropospheric refraction and delays, satellite and receiver clock biases, and orbital errors [1]. The ionospheric delay in the propagation of global positioning system (GPS signals is one of the main sources of error in GPS precise positioning and navigation. A dual-frequency GPS receiver can eliminate (to the first order the ionospheric delay through a linear combination of the L1 and L2 observations [2]. The most significant effect of ionospheric delay appear in case of using single frequency data. In this paper the single frequency data of concerned station are converted to dual frequency data by employing dual frequency data from 11 regional GPS stations distributed around it. Total electron content (TEC was calculated at every GPS station to produce the mathematical model of TEC which is a function of latitude (Φ and longitude (λ. By using this mathematical model the values of TEC and L2 can be predicted at the single frequency GPS station for each satellite, after that the comparison between predicted and observation values of TEC and L2 was performed. The estimation method and test results of the proposed method indicates that the difference between predicted and observation values is very small.

  2. SAR image registration in absolute coordinates using GPS carrier phase position and velocity information

    Energy Technology Data Exchange (ETDEWEB)

    Burgett, S.; Meindl, M. [Sandia National Labs., Albuquerque, NM (United States). Aided Navigation and Remote Sensing Systems

    1994-09-01

    It is useful in a variety of military and commercial application to accurately register the position of synthetic aperture radar (SAR) imagery in absolute coordinates. The two basic SAR measurements, range and doppler, can be used to solve for the position of the SAR image. Imprecise knowledge of the SAR collection platform`s position and velocity vectors introduce errors in the range and doppler measurements and can cause the apparent location of the SAR image on the ground to be in error by tens of meters. Recent advances in carrier phase GPS techniques can provide an accurate description of the collection vehicle`s trajectory during the image formation process. In this paper, highly accurate carrier phase GPS trajectory information is used in conjunction with SAR imagery to demonstrate a technique for accurate registration of SAR images in WGS-84 coordinates. Flight test data will be presented that demonstrates SAR image registration errors of less than 4 meters.

  3. Impacts of Satellite Orbit and Clock on Real-Time GPS Point and Relative Positioning.

    Science.gov (United States)

    Shi, Junbo; Wang, Gaojing; Han, Xianquan; Guo, Jiming

    2017-06-12

    Satellite orbit and clock corrections are always treated as known quantities in GPS positioning models. Therefore, any error in the satellite orbit and clock products will probably cause significant consequences for GPS positioning, especially for real-time applications. Currently three types of satellite products have been made available for real-time positioning, including the broadcast ephemeris, the International GNSS Service (IGS) predicted ultra-rapid product, and the real-time product. In this study, these three predicted/real-time satellite orbit and clock products are first evaluated with respect to the post-mission IGS final product, which demonstrates cm to m level orbit accuracies and sub-ns to ns level clock accuracies. Impacts of real-time satellite orbit and clock products on GPS point and relative positioning are then investigated using the P3 and GAMIT software packages, respectively. Numerical results show that the real-time satellite clock corrections affect the point positioning more significantly than the orbit corrections. On the contrary, only the real-time orbit corrections impact the relative positioning. Compared with the positioning solution using the IGS final product with the nominal orbit accuracy of ~2.5 cm, the real-time broadcast ephemeris with ~2 m orbit accuracy provided <2 cm relative positioning error for baselines no longer than 216 km. As for the baselines ranging from 574 to 2982 km, the cm-dm level positioning error was identified for the relative positioning solution using the broadcast ephemeris. The real-time product could result in <5 mm relative positioning accuracy for baselines within 2982 km, slightly better than the predicted ultra-rapid product.

  4. APPLICATION OF THE GPS/EGNOS SOLUTION FOR THE PRECISE POSITIONING OF AN AIRCRAFT VEHICLE

    Directory of Open Access Journals (Sweden)

    Kamil KRASUSKI

    2017-09-01

    Full Text Available The results of research concerning the implementation of the GNSS technique in the area of air navigation are presented in this article. In particular, a research test was conducted for the purposes of checking the functioning of a satellite-based augmentation system (SBAS to assist with air navigation. Ultimately, analyses of the parameters of accuracy, availability, continuity and integrity with the procedure when landing aircraft with an SBAS APV-I landing were conducted. The navigation and observation data of the GPS system and differential European Geostationary Navigation Overlay Service (EGNOS corrections were used in the research test. The navigation and observation data of the GPS system in the RINEX format were registered through the Topcon Hiper Pro receiver placed in the cabin of pilots in the Cessna 172 aircraft during a flight experiment conducted in Dęblin in 2010. The coordinates of the Cessna 172 aircraft in the ellipsoid BLh frame were reconstructed by using the solution offered by the single point positioning (SPP method in the RTKLIB program. The accuracy when setting coordinates of the aircraft is higher than 2.4 m in the horizontal plane and better than 4 m in the vertical plane. The integrity of the satellite positioning is higher than 15 m in the horizontal plane and better than 21.1 m in the vertical plane. The availability of the constellation of GPS/EGNOS satellites equalled 100% during the flight experiment, which confirms that the loss of continuity when determining the position of the aircraft did not occur. The parameters of the accuracy and the integrity with International Civil Aviation Organization (ICAO technical standards were compared in this article. The results of the conducted test shows that the presented research methods can be applied in the precise positioning of the aircraft when using the GPS/EGNOS solution for air navigation.

  5. Conceptual Approach for Precise Relative Positioning with Miniaturized GPS Loggers and Experimental Results

    Science.gov (United States)

    2010-03-01

    Approach for Precise Relative Positioning with Miniaturized GPS Loggers and Experimental Results ( ) min 1 2 =∑ = m j jf (20) jbijbij DDf Φ−Φ...residual based test statistic: ( ) jnnjnnj m j j DDf m f Φ−Φ= − ≈ −− =∑ ˆ~ 1 RMS ,1,1 1 2 f (35) For sampling rates of 1 Hz or higher, ( )fRMS is very

  6. Performance improvement for GPS single frequency kinematic relative positioning under poor satellite visibility

    OpenAIRE

    Chen, Wantong

    2016-01-01

    Reliable ambiguity resolution in difficult environments such as during setting/rising events of satellites or during limited satellite visibility is a significant challenge for GPS single frequency kinematic relative positioning. Here, a recursive estimation method combining both code and carrier phase measurements was developed that can tolerate recurrent satellite setting/rising and accelerate initialization in motion. We propose an ambiguity dimension expansion method by utilizing the part...

  7. Global positioning systems (GPS) and microtechnology sensors in team sports: a systematic review.

    Science.gov (United States)

    Cummins, Cloe; Orr, Rhonda; O'Connor, Helen; West, Cameron

    2013-10-01

    Use of Global positioning system (GPS) technology in team sport permits measurement of player position, velocity, and movement patterns. GPS provides scope for better understanding of the specific and positional physiological demands of team sport and can be used to design training programs that adequately prepare athletes for competition with the aim of optimizing on-field performance. The objective of this study was to conduct a systematic review of the depth and scope of reported GPS and microtechnology measures used within individual sports in order to present the contemporary and emerging themes of GPS application within team sports. A systematic review of the application of GPS technology in team sports was conducted. We systematically searched electronic databases from earliest record to June 2012. Permutations of key words included GPS; male and female; age 12-50 years; able-bodied; and recreational to elite competitive team sports. The 35 manuscripts meeting the eligibility criteria included 1,276 participants (age 11.2-31.5 years; 95 % males; 53.8 % elite adult athletes). The majority of manuscripts reported on GPS use in various football codes: Australian football league (AFL; n = 8), soccer (n = 7), rugby union (n = 6), and rugby league (n = 6), with limited representation in other team sports: cricket (n = 3), hockey (n = 3), lacrosse (n = 1), and netball (n = 1). Of the included manuscripts, 34 (97 %) detailed work rate patterns such as distance, relative distance, speed, and accelerations, with only five (14.3 %) reporting on impact variables. Activity profiles characterizing positional play and competitive levels were also described. Work rate patterns were typically categorized into six speed zones, ranging from 0 to 36.0 km·h⁻¹, with descriptors ranging from walking to sprinting used to identify the type of activity mainly performed in each zone. With the exception of cricket, no standardized speed zones or definitions were observed within or

  8. Automated time activity classification based on global positioning system (GPS tracking data

    Directory of Open Access Journals (Sweden)

    Wu Jun

    2011-11-01

    Full Text Available Abstract Background Air pollution epidemiological studies are increasingly using global positioning system (GPS to collect time-location data because they offer continuous tracking, high temporal resolution, and minimum reporting burden for participants. However, substantial uncertainties in the processing and classifying of raw GPS data create challenges for reliably characterizing time activity patterns. We developed and evaluated models to classify people's major time activity patterns from continuous GPS tracking data. Methods We developed and evaluated two automated models to classify major time activity patterns (i.e., indoor, outdoor static, outdoor walking, and in-vehicle travel based on GPS time activity data collected under free living conditions for 47 participants (N = 131 person-days from the Harbor Communities Time Location Study (HCTLS in 2008 and supplemental GPS data collected from three UC-Irvine research staff (N = 21 person-days in 2010. Time activity patterns used for model development were manually classified by research staff using information from participant GPS recordings, activity logs, and follow-up interviews. We evaluated two models: (a a rule-based model that developed user-defined rules based on time, speed, and spatial location, and (b a random forest decision tree model. Results Indoor, outdoor static, outdoor walking and in-vehicle travel activities accounted for 82.7%, 6.1%, 3.2% and 7.2% of manually-classified time activities in the HCTLS dataset, respectively. The rule-based model classified indoor and in-vehicle travel periods reasonably well (Indoor: sensitivity > 91%, specificity > 80%, and precision > 96%; in-vehicle travel: sensitivity > 71%, specificity > 99%, and precision > 88%, but the performance was moderate for outdoor static and outdoor walking predictions. No striking differences in performance were observed between the rule-based and the random forest models. The random forest model was fast

  9. Inertial and GPS data integration for positioning and tracking of GPR

    Science.gov (United States)

    Chicarella, Simone; D'Alvano, Alessandro; Ferrara, Vincenzo; Frezza, Fabrizio; Pajewski, Lara

    2015-04-01

    Nowadays many applications and studies use a Global Positioning System (GPS) to integrate Ground-Penetrating Radar (GPR) data [1-2]. The aim is the production of detailed detection maps that are geo-referenced and superimposable on geographic maps themes. GPS provides data to determine static positioning, and to track the mobile detection system path on the land. A low-cost standard GPS, like GPS-622R by RF Solutions Ltd, allows accuracy around 2.5 m CEP (Circular Error Probability), and a maximum update rate of 10 Hz. These accuracy and update rate are satisfying values when we evaluate positioning datum, but they are unsuitable for precision tracking of a speedy-mobile GPR system. In order to determine the relative displacements with respect to an initial position on the territory, an Inertial Measurement Unit (IMU) can be used. Some inertial-system applications for GPR tracking have been presented in recent studies [3-4]. The integration of both GPS and IMU systems is the aim of our work, in order to increase GPR applicability, e.g. the case of a GPR mounted on an unmanned aerial vehicle for the detection of people buried under avalanches [5]. In this work, we will present the design, realization and experimental characterization of our electronic board that includes GPS-622R and AltIMU-10 v3 by Pololu. The latter comprises an inertial-measurement unit and an altimeter. In particular, the IMU adopts L3GD20 gyro and LSM303D accelerometer and magnetometer; the digital barometer LPS331AP provides data for altitude evaluation. The prototype of our system for GPR positioning and tracking is based on an Arduino microcontroller board. Acknowledgement This work benefited from networking activities carried out within the EU funded COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar. ' References [1] M. Solla, X. Núñez-Nieto, M. Varela-González, J. Martínez-Sánchez, and P. Arias, 'GPR for Road Inspection: georeferencing and efficient

  10. Intelligent Sensor Positioning and Orientation Through Constructive Neural Network-Embedded INS/GPS Integration Algorithms

    Directory of Open Access Journals (Sweden)

    Kai-Wei Chiang

    2010-10-01

    Full Text Available Mobile mapping systems have been widely applied for acquiring spatial information in applications such as spatial information systems and 3D city models. Nowadays the most common technologies used for positioning and orientation of a mobile mapping system include a Global Positioning System (GPS as the major positioning sensor and an Inertial Navigation System (INS as the major orientation sensor. In the classical approach, the limitations of the Kalman Filter (KF method and the overall price of multi-sensor systems have limited the popularization of most land-based mobile mapping applications. Although intelligent sensor positioning and orientation schemes consisting of Multi-layer Feed-forward Neural Networks (MFNNs, one of the most famous Artificial Neural Networks (ANNs, and KF/smoothers, have been proposed in order to enhance the performance of low cost Micro Electro Mechanical System (MEMS INS/GPS integrated systems, the automation of the MFNN applied has not proven as easy as initially expected. Therefore, this study not only addresses the problems of insufficient automation in the conventional methodology that has been applied in MFNN-KF/smoother algorithms for INS/GPS integrated systems proposed in previous studies, but also exploits and analyzes the idea of developing alternative intelligent sensor positioning and orientation schemes that integrate various sensors in more automatic ways. The proposed schemes are implemented using one of the most famous constructive neural networks––the Cascade Correlation Neural Network (CCNNs––to overcome the limitations of conventional techniques based on KF/smoother algorithms as well as previously developed MFNN-smoother schemes. The CCNNs applied also have the advantage of a more flexible topology compared to MFNNs. Based on the experimental data utilized the preliminary results presented in this article illustrate the effectiveness of the proposed schemes compared to smoother algorithms

  11. Intelligent sensor positioning and orientation through constructive neural network-embedded INS/GPS integration algorithms.

    Science.gov (United States)

    Chiang, Kai-Wei; Chang, Hsiu-Wen

    2010-01-01

    Mobile mapping systems have been widely applied for acquiring spatial information in applications such as spatial information systems and 3D city models. Nowadays the most common technologies used for positioning and orientation of a mobile mapping system include a Global Positioning System (GPS) as the major positioning sensor and an Inertial Navigation System (INS) as the major orientation sensor. In the classical approach, the limitations of the Kalman Filter (KF) method and the overall price of multi-sensor systems have limited the popularization of most land-based mobile mapping applications. Although intelligent sensor positioning and orientation schemes consisting of Multi-layer Feed-forward Neural Networks (MFNNs), one of the most famous Artificial Neural Networks (ANNs), and KF/smoothers, have been proposed in order to enhance the performance of low cost Micro Electro Mechanical System (MEMS) INS/GPS integrated systems, the automation of the MFNN applied has not proven as easy as initially expected. Therefore, this study not only addresses the problems of insufficient automation in the conventional methodology that has been applied in MFNN-KF/smoother algorithms for INS/GPS integrated systems proposed in previous studies, but also exploits and analyzes the idea of developing alternative intelligent sensor positioning and orientation schemes that integrate various sensors in more automatic ways. The proposed schemes are implemented using one of the most famous constructive neural networks--the Cascade Correlation Neural Network (CCNNs)--to overcome the limitations of conventional techniques based on KF/smoother algorithms as well as previously developed MFNN-smoother schemes. The CCNNs applied also have the advantage of a more flexible topology compared to MFNNs. Based on the experimental data utilized the preliminary results presented in this article illustrate the effectiveness of the proposed schemes compared to smoother algorithms as well as the MFNN

  12. Application of TaiWan Ionosphere Model to Single-Frequency Ionospheric Delay Correction for GPS Static Position Positioning

    Science.gov (United States)

    Macalalad, E. P.; Tsai, L.; Wu, J.

    2011-12-01

    Ionospheric delay is one of the major sources of error in GPS positioning and navigation. This error in both pseudorange and phase ranges can vary depending on the location of observation, local time, season, solar cycle and geomagnetic activity. This effect can be practically removed using dual-frequency receivers. However, these types of receivers are very expensive and thus, impractical for most users. Therefore, for single-frequency receivers, ionosphere is usually modeled to attempt to remove this effect analytically. Numerous ionosphere models have been introduced in the past. Some of which are the Klobuchar (or broadcast) model and the global ionosphere map (GIM) provided by the International GNSS Service (IGS). In this paper, another model, called the TaiWan Ionosphere Model (TWIM) was used to correct this effect. TWIM is a three dimensional ionospheric electron (ne) density model derived from FormoSat3/COSMIC GPS Radio Occultation measurements, was used to calculate ionospheric delay for GPS single-frequency positioning. The ne profiles were used to calculate the slant TEC (STEC) between a receiver and each GPS satellite and correct the pseudorange single-frequency observations. The corrected pseudorange for every epoch was used to calculate the position of the receiver. Observations were made in a low-latitude location near one of the peaks of the equatorial anomaly. It was shown that TEC maps generated using TWIM exhibited detailed structure of the ionosphere, whereas Klobuchar and GIM only provided the basic diurnal and geographic features of the ionosphere. Also, it was shown that for static point positioning TWIM provides more accurate and more precise positioning than the Klobuchar and GIM models. That is, on the average, the horizontal accuracy, represented by the circular error probable (CEP), distance RMS (DRMS) and twice the DRMS (2DRMS), were better by 15-18% as compared with the CEP, DRMS and 2DRMS of uncorrected, Klobuchar and GIM. Moreover

  13. Global Positioning System Technology (GPS for Psychological Research: A Test of Convergent and Nomological Validity

    Directory of Open Access Journals (Sweden)

    Pedro eWolf

    2013-06-01

    Full Text Available The purpose of this paper is to examine the convergent and nomological validity of a GPS-based measure of daily activity, operationalized as Number of Places Visited (NPV. Relations among the GPS-based measure and two self-report measures of NPV, as well as relations among NPV and two factors made up of self-reported individual differences were examined. The first factor was composed of variables related to an Active Lifestyle (AL (e.g. positive affect, extraversion… and the second factor was composed of variables related to a Sedentary Lifestyle (SL (e.g. depression, neuroticism…. NPV was measured over a four-day period. This timeframe was made up of two week and two weekend days. A bi-variate analysis established one level of convergent validity and a Split-Plot GLM examined convergent validity, nomological validity, and alternative hypotheses related to constraints on activity throughout the week simultaneously. The first analysis revealed significant correlations among NPV measures- weekday, weekend, and the entire four day blocks, supporting the convergent validity of the Diary-, Google Maps-, and GPS-NPV measures. Results from the second analysis, indicating non-significant mean differences in NPV regardless of method, also support this conclusion. We also found that AL is a statistically significant predictor of NPV no matter how NPV was measured. We did not find a statically significant relation among NPV and SL. These results permit us to infer that the GPS-based NPV measure has convergent and nomological validity.

  14. Global Application of TaiWan Ionospheric Model to Single-Frequency GPS Positioning

    Science.gov (United States)

    Macalalad, E.; Tsai, L. C.; Wu, J.

    2012-04-01

    Ionospheric delay is one the major sources of error in GPS positioning and navigation. This error in both pseudorange and phase ranges vary depending on the location of observation, local time, season, solar cycle and geomagnetic activity. For single-frequency receivers, this delay is usually removed using ionospheric models. Two of them are the Klobuchar, or broadcast, model and the global ionosphere map (GIM) provided by the International GNSS Service (IGS). In this paper, a three dimensional ionospheric electron (ne) density model derived from FormoSat3/COSMIC GPS Radio Occultation measurements, called the TaiWan Ionosphere Model, is used. It was used to calculate the slant total electron content (STEC) between receiver and GPS satellites to correct the pseudorange single-frequency observations. The corrected pseudorange for every epoch was used to determine a more accurate position of the receiver. Observations were made in July 2, 2011(Kp index = 0-2) in five randomly selected sites across the globe, four of which are IGS stations (station ID: cnmr, coso, irkj and morp) while the other is a low-cost single-frequency receiver located in Chungli City, Taiwan (ID: isls). It was illustrated that TEC maps generated using TWIM exhibited a detailed structure of the ionosphere, whereas Klobuchar and GIM only provided the basic diurnal and geographic features of the ionosphere. Also, it was shown that for single-frequency static point positioning TWIM provides more accurate and more precise positioning than the Klobuchar and GIM models for all stations. The average %error of the corrections made by Klobuchar, GIM and TWIM in DRMS are 3.88%, 0.78% and 17.45%, respectively. While the average %error in VRMS for Klobuchar, GIM and TWIM are 53.55%, 62.09%, 66.02%, respectively. This shows the capability of TWIM to provide a good global 3-dimensional ionospheric model.

  15. Precise orbit determination and point positioning using GPS, Glonass, Galileo and BeiDou

    Directory of Open Access Journals (Sweden)

    Tegedor J.

    2014-04-01

    Full Text Available State of the art Precise Point Positioning (PPP is currently based on dual-frequency processing of GPS and Glonass navigation systems. The International GNSS Service (IGS is routinely providing the most accurate orbit and clock products for these constellations, allowing point positioning at centimeter-level accuracy. At the same time, the GNSS landscape is evolving rapidly, with the deployment of new constellations, such as Galileo and BeiDou. The BeiDou constellation currently consists of 14 operational satellites, and the 4 Galileo In-Orbit Validation (IOV satellites are transmitting initial Galileo signals. This paper focuses on the integration of Galileo and BeiDou in PPP, together with GPS and Glonass. Satellite orbits and clocks for all constellations are generated using a network adjustment with observation data collected by the IGS Multi-GNSS Experiment (MGEX, as well as from Fugro proprietary reference station network. The orbit processing strategy is described, and orbit accuracy for Galileo and BeiDou is assessed via orbit overlaps, for different arc lengths. Kinematic post-processed multi-GNSS positioning results are presented. The benefits of multiconstellation PPP are discussed in terms of enhanced availability and positioning accuracy.

  16. PRECISE POSITIONING OF UAVS – DEALING WITH CHALLENGING RTK-GPS MEASUREMENT CONDITIONS DURING AUTOMATED UAV FLIGHTS

    Directory of Open Access Journals (Sweden)

    F. Zimmermann

    2017-08-01

    Full Text Available For some years now, UAVs (unmanned aerial vehicles are commonly used for different mobile mapping applications, such as in the fields of surveying, mining or archeology. To improve the efficiency of these applications an automation of the flight as well as the processing of the collected data is currently aimed at. One precondition for an automated mapping with UAVs is that the georeferencing is performed directly with cm-accuracies or better. Usually, a cm-accurate direct positioning of UAVs is based on an onboard multi-sensor system, which consists of an RTK-capable (real-time kinematic GPS (global positioning system receiver and additional sensors (e.g. inertial sensors. In this case, the absolute positioning accuracy essentially depends on the local GPS measurement conditions. Especially during mobile mapping applications in urban areas, these conditions can be very challenging, due to a satellite shadowing, non-line-of sight receptions, signal diffraction or multipath effects. In this paper, two straightforward and easy to implement strategies will be described and analyzed, which improve the direct positioning accuracies for UAV-based mapping and surveying applications under challenging GPS measurement conditions. Based on a 3D model of the surrounding buildings and vegetation in the area of interest, a GPS geometry map is determined, which can be integrated in the flight planning process, to avoid GPS challenging environments as far as possible. If these challenging environments cannot be avoided, the GPS positioning solution is improved by using obstruction adaptive elevation masks, to mitigate systematic GPS errors in the RTK-GPS positioning. Simulations and results of field tests demonstrate the profit of both strategies.

  17. Classification of indoor-outdoor location using combined global positioning system (GPS) and temperature data for personal exposure assessment.

    Science.gov (United States)

    Lee, B; Lim, C; Lee, K

    2017-04-04

    The objectives of this study was to determine the accuracy of indoor-outdoor classification based on GPS and temperature data in three different seasons. In the present study, a global positioning system (GPS) was used alongside temperature data collected in the field by a technician who visited 53 different indoor locations during summer, autumn and winter. The indoor-outdoor location was determined by GPS data alone, and in combination with temperature data. Determination of location by the GPS signal alone, based on the loss of GPS signal and using the used number of satellites (NSAT) signal factor, simple percentage agreements of 73.6 ± 2.9%, 72.9 ± 3.4%, and 72.1 ± 3.1% were obtained for summer, autumn, and winter, respectively. However, when temperature and GPS data were combined, simple percentage agreements were significantly improved (87.9 ± 3.3%, 84.1 ± 2.8%, and 86.3 ± 3.1%, respectively). A temperature criterion for indoor-outdoor determination of ~ Δ 2°C for 2 min could be applied during all three seasons. The results showed that combining GPS and temperature data improved the accuracy of indoor-outdoor determination.

  18. Performance improvement for GPS single frequency kinematic relative positioning under poor satellite visibility.

    Science.gov (United States)

    Chen, Wantong

    2016-01-01

    Reliable ambiguity resolution in difficult environments such as during setting/rising events of satellites or during limited satellite visibility is a significant challenge for GPS single frequency kinematic relative positioning. Here, a recursive estimation method combining both code and carrier phase measurements was developed that can tolerate recurrent satellite setting/rising and accelerate initialization in motion. We propose an ambiguity dimension expansion method by utilizing the partial ambiguity relevance of previous and current observations. In essence, this method attempts to integrate all useful information into the recursive estimation equation and performs a better least squares adjustment. Using this method, the success rate of the extended ambiguity estimation is independent of the satellite setting and shows robust performance despite poor satellite visibility. Our model allows integration of other useful information into the recursive process. Actual experiments in urban environments demonstrate that the proposed algorithm can improve the reliability and availability of relative positioning.

  19. A new analytical method for the classification of time-location data obtained from the global positioning system (GPS).

    Science.gov (United States)

    Kim, Taehyun; Lee, Kiyoung; Yang, Wonho; Yu, Seung Do

    2012-08-01

    Although the global positioning system (GPS) has been suggested as an alternative way to determine time-location patterns, its use has been limited. The purpose of this study was to evaluate a new analytical method of classifying time-location data obtained by GPS. A field technician carried a GPS device while simulating various scripted activities and recorded all movements by the second in an activity diary. The GPS device recorded geological data once every 15 s. The daily monitoring was repeated 18 times. The time-location data obtained by the GPS were compared with the activity diary to determine selection criteria for the classification of the GPS data. The GPS data were classified into four microenvironments (residential indoors, other indoors, transit, and walking outdoors); the selection criteria used were used number of satellites (used-NSAT), speed, and distance from residence. The GPS data were classified as indoors when the used-NSAT was below 9. Data classified as indoors were further classified as residential indoors when the distance from the residence was less than 40 m; otherwise, they were classified as other indoors. Data classified as outdoors were further classified as being in transit when the speed exceeded 2.5 m s(-1); otherwise, they were classified as walking outdoors. The average simple percentage agreement between the time-location classifications and the activity diary was 84.3 ± 12.4%, and the kappa coefficient was 0.71. The average differences between the time diary and the GPS results were 1.6 ± 2.3 h for the time spent in residential indoors, 0.9 ± 1.7 h for the time spent in other indoors, 0.4 ± 0.4 h for the time spent in transit, and 0.8 ± 0.5 h for the time spent walking outdoors. This method can be used to determine time-activity patterns in exposure-science studies.

  20. Estimation of crustal movements using the Global Positioning System (GPS measurements along Nile Valley area, Egypt from 2007 to 2012

    Directory of Open Access Journals (Sweden)

    Kamal Sakr

    2015-06-01

    The present study aimed to determine the recent crustal movement parameters along the Nile Valley using the Global Positioning System (GPS measurements. To achieve this mission, a GPS network consisting of ten geodetic stations has been established on both sides along the Nile Valley area. GPS measurements have been collected from 2007 to 2012. The collected data were processed using Bernese 5.0 Software. The result of the data analysis indicates that the rate of local velocity is small ranging from 1 to 4 mm/year. This rate is consistent with the low rate of occurrence of recent earthquakes activity along the Nile Valley area. But, the results obtained from the calculation of the regional velocity indicated that the velocity of the GPS stations including the African Plate motion is about 25 mm/year in the northeast direction which is consistent with the African Plate motion direction.

  1. TONGKAT ISTIWA‘, GLOBAL POSITIONING SYSTEM (GPS DAN GOOGLE EARTH UNTUK MENENTUKAN TITIK KOORDINAT BUMI DAN APLIKASINYA DALAM PENENTUAN ARAH KIBLAT

    Directory of Open Access Journals (Sweden)

    Anisah Budiwati

    2016-04-01

    Full Text Available There are at least three ways to determine the position or the coordinates of a spot on the Earth's surface. They are: istiwa' sticks, Global Positioning System (GPS, and Google Earth. Istiwa' stick is used without technology operations, while GPS and Google Earth are used with technology. Until now, the use of GPS and Google Earth is still a passively consumptive, without their critical analytical effort. This qualitative research using descriptive analytic mathematical methods. The objective of this study is the to know the theory, applications, and accuracy of the istiwa' stick, GPS, and Google Earth comparatively. The study found that the istiwa' stick is one of the alternatives way to determine the coordinates of the Earth which uses the theory of spherical trigonometry calculations simply without assistance. Whereas GPS and Google Earth use principles of geodetic scientifically. In terms of applications, the most practical and accurate is GPS, and then followed by Google Earth, and the last is istiwa' stick.

  2. A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning

    Directory of Open Access Journals (Sweden)

    Wenwei Zuo

    2018-01-01

    Full Text Available Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS/Global Positioning System (GPS positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API of the original standard Global Navigation Satellite System (GNSS to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to

  3. A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning.

    Science.gov (United States)

    Zuo, Wenwei; Guo, Chi; Liu, Jingnan; Peng, Xuan; Yang, Min

    2018-01-10

    Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI) exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS)/Global Positioning System (GPS) positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API) of the original standard Global Navigation Satellite System (GNSS) to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to meet the

  4. GPS for land surveyors

    CERN Document Server

    Van Sickle, Jan

    2008-01-01

    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

  5. Multi-hypothesis GPS and Electronic Fence Data Fusion for Safety-Critical Positioning in RailwayWorksites

    DEFF Research Database (Denmark)

    Figueiras, Joao; Grønbæk, Lars Jesper; Schwefel, Hans-Peter

    2013-01-01

    of wearable GPS receivers and electronic fences strategically placed at the worksite. The proposed data fusion algorithm comprises a Kalman Filter (KF) for filtering GPS observations and a Hidden Markov Model (HMM) for fusion with fence data. A Multiple-Hypothesis Tracking (MHT) mechanism is used to handle......Safety-critical applications often use position information as a mean of assessing the safety level of people. For this reason, such information is required to be precise in terms of accuracy and timeliness. This paper regards position mechanisms for personalized warning systems for railway workers...... multiple workers within the worksite as a mean to compensate the inability of the fence to distinguish the workers. The proposed solution is analyzed under experimental setups. The obtained results outperformed a GPS-only solution and the previously proposed solution by reducing or even removing false...

  6. Multi-hypothesis GPS and electronic fence data fusion for safety-critical positioning in railway worksites

    DEFF Research Database (Denmark)

    Figueiras, Joao; Gronbaek, Jesper; Schwefel, Hans-Peter

    2013-01-01

    of wearable GPS receivers and electronic fences strategically placed at the worksite. The proposed data fusion algorithm comprises a Kalman Filter (KF) for filtering GPS observations and a Hidden Markov Model (HMM) for fusion with fence data. A Multiple-Hypothesis Tracking (MHT) mechanism is used to handle......Safety-critical applications often use position information as a mean of assessing the safety level of people. For this reason, such information is required to be precise in terms of accuracy and timeliness. This paper regards position mechanisms for personalized warning systems for railway workers...... multiple workers within the worksite as a mean to compensate the inability of the fence to distinguish the workers. The proposed solution is analyzed under experimental setups. The obtained results outperformed a GPS-only solution and the previously proposed solution by reducing or even removing false...

  7. The use of GPS for Handling Lack of Indoor Constraints in Particle Filter-based Inertial Positioning

    DEFF Research Database (Denmark)

    Toftkjær, Thomas; Kjærgaard, Mikkel Baun

    Particle filter-based inertial positioning promises infrastructure-less positioning, but previous research have not provided an understanding of, how the positioning accuracy of such systems depends on the layout of building structures. This poster presents initial result for the impact...... of the layout of building structures on the positioning accuracy using a particle filter-based inertial positioning system named Pro-Position. We also consider methods for using GPS positioning with particle filter-based inertial positioningto improve accuracy in areas, where positioning is poor because of lack...

  8. A Tightly-Coupled GPS/INS/UWB Cooperative Positioning Sensors System Supported by V2I Communication.

    Science.gov (United States)

    Wang, Jian; Gao, Yang; Li, Zengke; Meng, Xiaolin; Hancock, Craig M

    2016-06-27

    This paper investigates a tightly-coupled Global Position System (GPS)/Ultra-Wideband (UWB)/Inertial Navigation System (INS) cooperative positioning scheme using a Robust Kalman Filter (RKF) supported by V2I communication. The scheme proposes a method that uses range measurements of UWB units transmitted among the terminals as augmentation inputs of the observations. The UWB range inputs are used to reform the GPS observation equations that consist of pseudo-range and Doppler measurements and the updated observation equation is processed in a tightly-coupled GPS/UWB/INS integrated positioning equation using an adaptive Robust Kalman Filter. The result of the trial conducted on the roof of the Nottingham Geospatial Institute (NGI) at the University of Nottingham shows that the integrated solution provides better accuracy and improves the availability of the system in GPS denied environments. RKF can eliminate the effects of gross errors. Additionally, the internal and external reliabilities of the system are enhanced when the UWB observables received from the moving terminals are involved in the positioning algorithm.

  9. A Tightly-Coupled GPS/INS/UWB Cooperative Positioning Sensors System Supported by V2I Communication

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-06-01

    Full Text Available This paper investigates a tightly-coupled Global Position System (GPS/Ultra-Wideband (UWB/Inertial Navigation System (INS cooperative positioning scheme using a Robust Kalman Filter (RKF supported by V2I communication. The scheme proposes a method that uses range measurements of UWB units transmitted among the terminals as augmentation inputs of the observations. The UWB range inputs are used to reform the GPS observation equations that consist of pseudo-range and Doppler measurements and the updated observation equation is processed in a tightly-coupled GPS/UWB/INS integrated positioning equation using an adaptive Robust Kalman Filter. The result of the trial conducted on the roof of the Nottingham Geospatial Institute (NGI at the University of Nottingham shows that the integrated solution provides better accuracy and improves the availability of the system in GPS denied environments. RKF can eliminate the effects of gross errors. Additionally, the internal and external reliabilities of the system are enhanced when the UWB observables received from the moving terminals are involved in the positioning algorithm.

  10. Observations of ocean tidal load response in South America from subdaily GPS positions

    Science.gov (United States)

    Martens, Hilary R.; Simons, Mark; Owen, Susan; Rivera, Luis

    2016-06-01

    We explore Earth's elastic deformation response to ocean tidal loading (OTL) using kinematic Global Positioning System (GPS) observations and forward-modelled predictions across South America. Harmonic coefficients are extracted from up to 14 yr of GPS-inferred receiver locations, which we estimate at 5 min intervals using precise point positioning. We compare the observed OTL-induced surface displacements against predictions derived from spherically symmetric, non-rotating, elastic and isotropic (SNREI) Earth models. We also compare sets of modelled predictions directly for various ocean-tide and Earth-model combinations. The vector differences between predicted displacements computed using separate ocean-tide models reveal uniform-displacement components common to all stations in the South America network. Removal of the network-mean OTL-induced displacements from each site substantially reduces the vector differences between observed and predicted displacements. We focus on the dominant astronomical tidal harmonics from three distinct frequency bands: semidiurnal (M2), diurnal (O1) and fortnightly (Mf). In each band, the observed OTL-induced surface displacements strongly resemble the modelled displacement-response patterns, and the residuals agree to about 0.3 mm or better. Even with the submillimetre correspondence between observations and predictions, we detect regional-scale spatial coherency in the final set of residuals, most notably for the M2 harmonic. The spatial coherency appears relatively insensitive to the specific choice of ocean-tide or SNREI-Earth model. Varying the load model or 1-D elastic structure yields predicted OTL-induced displacement differences of order 0.1 mm or less for the network. Furthermore, estimates of the observational uncertainty place the noise level below the magnitude of the residual displacements for most stations, supporting our interpretation that random errors cannot account for the entire misfit. Therefore, the

  11. Training GPs in parent consultation skills. An evaluation of training for the Triple P-Positive Parenting Program.

    Science.gov (United States)

    Sanders, Matthew R; Tully, Lucy A; Turner, Karen M; Maher, Clare; McAuliffe, Christine

    2003-09-01

    The Triple P-Positive Parenting Program is a behavioural family intervention program that aims to prevent severe behavioral, emotional and developmental problems in children by enhancing the knowledge, skills, and confidence of parents. This study evaluated the effect of training general practitioners in the use of the primary care version of the TPP on their consultation skills, satisfaction and confidence in conducting consultations with parents. Participants were assigned to an experimental condition that involved a brief behaviorally oriented parent consultation skills training program or to a wait-list comparison group. Thirty-two GPs participated in the training. Fifteen participants attended the first workshop (intervention group) and 17 attended the second (wait-list comparison group). GPs who participated in the training reported greater satisfaction with the outcomes of their parent consultations and showed significantly greater use of targeted parent consultation skills than GPs in the wait-list comparison group. Observations of GP consultation skills during simulated patient interviews with parents showed there was a significant overall improvement in their interactional skills during parent consultations. There was a high level of satisfaction with the quality of training received by the GPs. This was a brief, cost effective program that had significant effects on participating GPs' skills, confidence and satisfaction with child consultations involving behavioral problems. Implications for public health approaches to the prevention of child psychopathology are discussed.

  12. Implementasi Sistem Informasi Geografis Daerah Pariwisata Kabupaten Temanggung Berbasis Android dengan Global Positioning System (GPS

    Directory of Open Access Journals (Sweden)

    Kartika Imam Santoso

    2016-02-01

    Full Text Available Pariwisata merupakan aspek yang berharga bagi suatu daerah, dan semakin banyak pengunjung maka dapat memajukan kesejahteraan masyarakat di sekitar obyek pariwisata. Kabupaten Temanggung memiliki banyak obyek pariwisata, penggunaan teknologi informasi seperti menggunakan aplikasi smartphone berbasis Android dapat digunakan untuk membantu wisatawan untuk mengenal daerah pariwisata dan mengetahui rute menuju ke obyek pariwisata yang diinginkan. Implementasi Sistem Informasi Geografis (SIG di daerah wisata Temanggung bertujuan untuk membangun aplikasi Wisata Temanggung berbasis Android dan menerapkan layanan Google Maps Application Programming Interface (API untuk memudahkan wisatawan dalam memperoleh informasi pemetaan lokasi objek wisata, rute dan fasilitas pendukung wisata yang ada di Kabupaten Temanggung. Metode yang digunakan adalah model proses air terjun (waterfall. Implementasi Aplikasi Wisata Temanggung menggunakan pemrograman Javascript dengan Eclipse Luna, basis data SQLite, serta peta yang bersumber dari Google Maps API. Hasilnya berupa aplikasi Wisata Temanggung berbasis Android yang membantu memudahkan wisatawan dalam memperoleh informasi tentang obyek wisata alam, buatan, budaya, kuliner, hotel dan rute dari lokasi sekarang ke lokasi obyek wisata yang diinginkan di Kabupaten Temanggung dengan bantuan Global Positioning System (GPS.  

  13. Implementasi Sistem Informasi Geografis Daerah Pariwisata Kota Semarang Berbasis Android dengan Global Positioning System (GPS

    Directory of Open Access Journals (Sweden)

    Richard RF Siahaan

    2014-01-01

    Full Text Available Pariwisata merupakan aspek yang berharga bagi suatu daerah, dengan adanya daerah wisata maka dapat memajukan kesejahteraan masyarakat sekitar. Kota Semarang memiliki daerah pariwisata yang sangat banyak, apabila sarana dan prasarana yang ada dikembangkan lebih lanjut maka dipastikan peningkatan parwisata di Kota Semarang akan semakin bertambah. Penggunaan Teknologi Informasi dapat memajukan daerah pariwisata, sehingga daerah pariwisata dapat dikenal oleh wisatawan yang ingin berkunjung ke Semarang. Sistem Informasi Geografis yang dibangun menggunakan platform android. Pada Tugas Akhir ini menggunakan Java sebagai bahasa pemorgraman dengan eclipse sebagai perangkat lunak pengembangan. Penggunaan Google Map API sebagai fungsi utama peta dalam menjalankan aplikasi serta PHP sebagai bahasa pemorgaraman sisi server dan MySQL dalam penggunaan basis data. Hasil dari perancangan Aplikasi Sistem Infomasi Geografis Kota Semarang berbasis Android ini nantinya akan memberikan informasi dalam bentuk peta yang dapat digunakan sebagai referensi bagi wisatawan yang berkunjung. Penggunaan Global Positioning System (GPS dalam aplikasi ini menjadi hal yang sangat penting dalam menentukan keberadaan wisatawan. Selain itu terdapat rute untuk menuju objek wisata yang dipilih, dalam aplikasi ini juga tersedia fasilitas-fasilitas umum seperti ATM dan Bank, Bandara, Mesjid, Gereja, Rumah Sakit dan lainnya.

  14. Low-cost, 4-system, precise GNSS positioning: a GPS, Galileo, BDS and QZSS ionosphere-weighted RTK analysis

    Science.gov (United States)

    Odolinski, Robert; Teunissen, Peter J. G.

    2017-12-01

    With the combination of emerging GNSSs, single-frequency (SF) precise RTK positioning becomes possible. In this contribution we evaluate such low-cost ublox receiver and antenna performance when combining real data of four CDMA systems, namely L1 GPS, E1 Galileo, L1 QZSS, and B1 BDS. Comparisons are made to more expensive dual-frequency (DF) GPS receivers and antennas. The formal and empirical ambiguity success rates and positioning precisions will first be evaluated while making use of L1+E1, so as to investigate whether instantaneous SF RTK is possible without the need of B1 BDS or L1 QZSS. This is followed by an analysis of the SF 4-system model performance when the residual ionosphere can be ignored and modeled as a function of the baseline length, respectively. The analyses are conducted for a location in Dunedin, New Zealand, and compared to Perth, Australia with the better visibility of BDS and QZSS. The results indicate that successful instantaneous and precise RTK positioning is feasible while using L1 GPS and E1 Galileo data, and that the SF 4-system model is competitive to DF GPS even when residual ionospheric delays are present. We finally demonstrate that when the impact from the ionosphere increases and more than one epoch is needed for successful ambiguity resolution, the SF 4-system model performance can still remain competitive with the DF GPS receivers. This is particularly true in Perth with more satellites and when higher than customary elevation cut-off angles need to be used to avoid low-elevation multipath.

  15. Cardiovascular effects of sub-daily levels of ambient fine particles: a systematic review

    Directory of Open Access Journals (Sweden)

    Perron Stéphane

    2010-06-01

    Full Text Available Abstract Background While the effects of daily fine particulate exposure (PM have been well reviewed, the epidemiological and physiological evidence of cardiovascular effects associated to sub-daily exposures has not. We performed a theoretical model-driven systematic non-meta-analytical literature review to document the association between PM sub-daily exposures (≤6 hours and arrhythmia, ischemia and myocardial infarction (MI as well as the likely mechanisms by which sub-daily PM exposures might induce these acute cardiovascular effects. This review was motivated by the assessment of the risk of exposure to elevated sub-daily levels of PM during fireworks displays. Methods Medline and Elsevier's EMBase were consulted for the years 1996-2008. Search keywords covered potential cardiovascular effects, the pollutant of interest and the short duration of the exposure. Only epidemiological and experimental studies of adult humans (age > 18 yrs published in English were reviewed. Information on design, population and PM exposure characteristics, and presence of an association with selected cardiovascular effects or physiological assessments was extracted from retrieved articles. Results Of 231 articles identified, 49 were reviewed. Of these, 17 addressed the relationship between sub-daily exposures to PM and cardiovascular effects: five assessed ST-segment depression indicating ischemia, eight assessed arrhythmia or fibrillation and five considered MI. Epidemiologic studies suggest that exposure to sub-daily levels of PM is associated with MI and ischemic events in the elderly. Epidemiological studies of sub-daily exposures suggest a plausible biological mechanism involving the autonomic nervous system while experimental studies suggest that vasomotor dysfunction may also relate to the occurrence of MI and ischemic events. Conclusions Future studies should clarify associations between cardiovascular effects of sub-daily PM exposure with PM size

  16. High Classification Rates for Continuous Cow Activity Recognition using Low-cost GPS Positioning Sensors and Standard Machine Learning Techniques

    DEFF Research Database (Denmark)

    Godsk, Torben; Kjærgaard, Mikkel Baun

    2011-01-01

    In precision livestock farming, spotting cows in need of extra attention due to health or welfare issues are essential, since the time a farmer can devote to each animal is decreasing due to growing herd sizes and increasing efficiency demands. Often, the symptoms of health and welfare state...... changes, affects the behavior of the individual animal, e.g., changes in time spend on activities like standing, lying, eating or walking. Low-cost and infrastructure-less GPS positioning sensors attached to the animals’ collars give the opportunity to monitor the movements of cows and recognize cow...... activities. By preprocessing the raw cow position data, we obtain high classification rates using standard machine learning techniques to recognize cow activities. Our objectives were to (i) determine to what degree it is possible to robustly recognize cow activities from GPS positioning data, using low...

  17. Concurrent validity and test-retest reliability of a global positioning system (GPS) and timing gates to assess sprint performance variables.

    Science.gov (United States)

    Waldron, Mark; Worsfold, Paul; Twist, Craig; Lamb, Kevin

    2011-12-01

    There has been no previous investigation of the concurrent validity and reliability of the current 5 Hz global positioning system (GPS) to assess sprinting speed or the reliability of integrated GPS-accelerometer technology. In the present study, we wished to determine: (1) the concurrent validity and reliability of a GPS and timing gates to measure sprinting speed or distance, and (2) the reliability of proper accelerations recorded via GPS-accelerometer integration. Nineteen elite youth rugby league players performed two over-ground sprints and were simultaneously assessed using GPS and timing gates. The GPS measurements systematically underestimated both distance and timing gate speed. The GPS measurements were reliable for all variables of distance and speed (coefficient of variation [CV] = 1.62% to 2.3%), particularly peak speed (95% limits of agreement [LOA] = 0.00 ± 0.8 km · h(-1); CV = 0.78%). Timing gates were more reliable (CV = 1% to 1.54%) than equivalent GPS measurements. Accelerometer measurements were least reliable (CV = 4.69% to 5.16%), particularly for the frequency of proper accelerations (95% LOA = 1.00 ± 5.43; CV = 14.12%). Timing gates and GPS were found to reliably assess speed and distance, although the validity of the GPS remains questionable. The error found in accelerometer measurements indicates the limits of this device for detecting changes in performance.

  18. APLIKASI TEKNOLOGI GLOBAL POSITIONING SYSTEM (GPS DAN TELEPON SELULAR (GSM UNTUK MONITORING TITIK AKSESKENDARAAN DINAS UNNES

    Directory of Open Access Journals (Sweden)

    Agus Suryanto

    2012-02-01

    Full Text Available Pada penelitian ini dibuat sebuah sistem memanfaatkan GPS yang dipadukan dengan teknologi SMS telepon seluler yang digunakan untuk pelacakan kendaraan bergerak. Sebuah sistem mikroprosesor yang dilengkapi dengan GPS dan telepon seluler ditempatkan pada kendaraan, yang mana posisi kendaraan tersebut secara reguler dikirimkan melalui SMS ke komputer pengendali. Langkah kerja dari pengujian ini adalah (1 perancangan sisten, (2 pembuatan program, (3 perancangan format SMS, (4 pengujian system. Kesimpulan dari penelitian ini menunjukkan 1 perancangan sistem ini dapat mendeteksi objek yang dipantau melalui visualisasi pada peta digital. Pemilihan sistem ini dengan pengiriman data posisi melalui SMS mempunyai keuntungan yaitu lebih murah dalam pembangunan dan operasinya serta mudah dalam pembangunannya. 2 Posisi longitude dan latitude yang diambil dari modul GPS riceiver di handphone valid karena sama dengan yang diambil dengan laptop.

  19. Evaluation of a regional real-time precise positioning system based on GPS/BeiDou observations in Australia

    Science.gov (United States)

    Ding, Wenwu; Tan, Bingfeng; Chen, Yongchang; Teferle, Felix Norman; Yuan, Yunbin

    2018-02-01

    The performance of real-time (RT) precise positioning can be improved by utilizing observations from multiple Global Navigation Satellite Systems (GNSS) instead of one particular system. Since the end of 2012, BeiDou, independently established by China, began to provide operational services for users in the Asia-Pacific regions. In this study, a regional RT precise positioning system is developed to evaluate the performance of GPS/BeiDou observations in Australia in providing high precision positioning services for users. Fixing three hourly updated satellite orbits, RT correction messages are generated and broadcasted by processing RT observation/navigation data streams from the national network of GNSS Continuously Operating Reference Stations in Australia (AUSCORS) at the server side. At the user side, RT PPP is realized by processing RT data streams and the RT correction messages received. RT clock offsets, for which the accuracy reached 0.07 and 0.28 ns for GPS and BeiDou, respectively, can be determined. Based on these corrections, an accuracy of 12.2, 30.0 and 45.6 cm in the North, East and Up directions was achieved for the BeiDou-only solution after 30 min while the GPS-only solution reached 5.1, 15.3 and 15.5 cm for the same components at the same time. A further improvement of 43.7, 36.9 and 45.0 percent in the three directions, respectively, was achieved for the combined GPS/BeiDou solution. After the initialization process, the North, East and Up positioning accuracies were 5.2, 8.1 and 17.8 cm, respectively, for the BeiDou-only solution, while 1.5, 3.0, and 4.7 cm for the GPS-only solution. However, we only noticed a 20.9% improvement in the East direction was obtained for the GPS/BeiDou solution, while no improvements in the other directions were detected. It is expected that such improvements may become bigger with the increasing accuracy of the BeiDou-only solution.

  20. Standard Positioning Performance Evaluation of a Single-Frequency GPS Receiver Implementing Ionospheric and Tropospheric Error Corrections

    OpenAIRE

    Alban Rakipi; Bexhet Kamo; Shkelzen Cakaj; Algenti Lala

    2015-01-01

    This paper evaluates the positioning performance of a single-frequency software GPS receiver using Ionospheric and Tropospheric corrections. While a dual-frequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, a single-frequency user must remove or calibrate this error by other means. To remove the ionosphere error we take advantage of the Klobuchar correction model, while for troposphere error mitigation the Hopfield correction model is...

  1. The State of GPS Vertical Positioning Precision : Separation of Earth Processes by Space Geodesy

    CERN Document Server

    2003-01-01

    Observed signals in GPS data are the sum of noise and real crustal motions. Interpretation of the data depends on our ability to extract a signal of interest from the total signal. This workshop will highlight the difficulties associated with extracting a signal such as post-glacial rebound, plate tectonics or loading, from vertical geodetic data.

  2. MIVIS image geocoding experience on merging position attitude system data and public domain GPS stream (ASI-GeoDAF

    Directory of Open Access Journals (Sweden)

    S. Pignatti

    2006-06-01

    Full Text Available The use of airborne scanners involves geo-referencing problems, which are difficult because of the need to know the exact platform position and attitude for each scan line. The errors of the onboard navigation system are normally corrected using ground control point on the image. This post-processing correction procedure is too long in case of multiple flight campaigns, and besides it implies the need to have available 1:10000 orthophotoimages or maps in digital format. To optimize the above procedure a new method to correct MIVIS navigational data in the post-processing phase has been implemented. The procedure takes into consideration the GPS stream in Rinex format of common knowledge and findable on the web, acquired at the ground stations of the Geodetic Data Archiving Facilities provided by ASI. The application of this correction entails the assumption that the environmental variables affecting both onboard and geodetic GPS equally affect the position measurements. The airborne data correction was carried out merging the two data sets (onboard and ground station GPS to achieve a more precise aircraft trajectory. The present study compares the geo-coded images obtained by means of the two post-processing methods.

  3. Instantaneous geodetic positioning with 10-50 Hz GPS measurements: Noise characteristics and implications for monitoring networks

    Science.gov (United States)

    Genrich, Joachim F.; Bock, Yehuda

    2006-03-01

    Recent earthquake recordings from high-rate (1 Hz) continuous GPS stations in California indicate that even higher temporal resolution provided by modern GPS receivers is desirable. We measured seven baselines during time intervals devoid of detectable transient signals at sampling rates of 1-50 Hz with geodetic receivers from four manufacturers to investigate the noise characteristics of these data. Our tests over short distances (meters) to typical station spacing (tens of kilometers) of regional GPS networks show no loss of spatial resolution compared to 1-Hz samples. Measurement noise is red with the typical ramp profile of log-log spectra below about 0.5 Hz. Above this frequency, noise is essentially white. Low-pass filtering of high-rate positions achieves improved spatial resolution compared to decimated raw samples. Averaging 20-Hz measurements to 2-Hz samples on a 40-km baseline, for example, yields about 0.5 mm horizontal and about 3-4 mm vertical accuracy at high frequencies. These estimates are a factor of 2-2.5 better than for 2-Hz raw samples. The improvements in spatial resolution due to averaging at high frequencies are substantial and approach the theoretical "square-root-of-n" expectation for independent samples. However, since noise spectral densities rise rapidly below about 0.5-Hz, low-pass filtering is only effective above this frequency. These results have important implications for the design of continuous GPS networks for crustal deformation and structural monitoring and for positioning and attitude determination of dynamic platforms.

  4. INVESTIGATING DRIVERS' RESPONSES TO ROAD-USER CHARGES USING GLOBAL POSITIONING SYSTEM (GPS TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Neil THORPE

    2003-01-01

    Full Text Available This paper describes the design and implementation of a field trial of a GPS-based road-user charging system held in Newcastle upon Tyne, U.K. Employees from the University of Newcastle upon Tyne were recruited to participate in experiments of both point-based and distance-based charging. To avoid road-user charges for commuting to and from the University during the trial period, volunteers could choose either to reschedule the departure time of their trip or to use an alternative uncharged route. Virtual charging-points were implemented using GPS equipment and the on-board charging system designed and developed by the research team in Newcastle. The paper concludes with a discussion of the future directions for empirical research on road-user charging.

  5. Pengembangan Sistem Navigasi Otomatis pada UAV (Unmanned Aerial Vehicle) dengan GPS(Global Positioning System) Waypoint

    OpenAIRE

    Hidayat, Rahmad; Mardiyanto, Ronny

    2016-01-01

    UAV adalah salah satu wahana tanpa awak di udara yang mana dapat terbang tanpa pilot, menggunakan gaya aerodinamik untuk menghasilkan gaya angkat (lift), dapat terbang secara autonomous atau dioperasikan dengan radio kontrol. UAV digunakan untuk berbagai keperluan baik di lingkup militer maupun sipil. Pada tugas akhir ini dirancang dan direalisasikan pengembangan sistem navigasi otomatis pada UAV dengan GPS waypoint. Sistem ini menggunakan kontrol manual dan autopilot. Pada mode manual, ...

  6. Pengembangan Sistem Navigasi Otomatis Pada UAV (Unmanned Aerial Vehicle dengan GPS(Global Positioning System Waypoint

    Directory of Open Access Journals (Sweden)

    Rahmad Hidayat

    2017-01-01

    Full Text Available UAV adalah salah satu wahana tanpa awak di udara yang mana dapat terbang tanpa pilot, menggunakan gaya aerodinamik untuk menghasilkan gaya angkat (lift, dapat terbang secara autonomous atau dioperasikan dengan radio kontrol. UAV digunakan untuk berbagai keperluan baik di lingkup militer maupun sipil. Pada tugas akhir ini dirancang dan direalisasikan pengembangan sistem navigasi otomatis pada UAV dengan GPS waypoint. Sistem ini menggunakan kontrol manual dan autopilot. Pada mode manual, pengguna secara manual mengendalikan pergerakan pesawat melalui radio kontroler sedangkan pada mode autopilot pesawat dikendalikan oleh mikrokontroler Arduino Mega 2560 yang mengolah data-data sensor IMU (Inertial Measurement Unit yang didalamnya terdapat gyroscope dan accelerometer, GPS dan barometric altimeter sehingga dapat terbang secara otomatis dengan sesuai waypoint GPS yang dimasukkan. Mikrokontroler menerima dan menolah data dari sensor dan menghasilkan keluaran untuk menggerakkan servo aktuator. Pengolahan data dari sensor menggunakan kontrol PID (Proportional Integral Derivative. Pesawat akan terkoneksi dengan ground station melalui perangkat telemetri untuk mengirimkan data penerbangan ke darat. Sistem navigasi ini diharapkan dapat secara tepat mengarahkan pesawat menuju satu titik atau lebih dengan toleransi kesalahan ≤ 30 meter pada ketinggian 30-100 meter. Selain itu pesawat diharapkan dapat terbang dengan radius ± 2 km dari ground station. Hasil dari pengujian dapat dilaksanakan kontrol manual dan otomatis pada UAV melalui 5 channel (aileron, elevator, throttle, rudder dan saklar. Distorsi pada kontrol manual diminimalisir dengan memperbesar faktor pembagi sinyal PWM sebesar 50μs-100μs. Kontrol otomatis dapat menstabilkan sikap pesawat di udara (sudut roll 45° dan sudut pitch 30° Setting Kp 1,2 dan Ki 0,01, setting Kp navigasi GPS 0,2 Ki 0,01 dan Kd 4 dengan sudut roll maksimal 15°.

  7. Lightweight UAV with on-board photogrammetry and single-frequency GPS positioning for metrology applications

    Science.gov (United States)

    Daakir, M.; Pierrot-Deseilligny, M.; Bosser, P.; Pichard, F.; Thom, C.; Rabot, Y.; Martin, O.

    2017-05-01

    This article presents a coupled system consisting of a single-frequency GPS receiver and a light photogrammetric quality camera embedded in an Unmanned Aerial Vehicle (UAV). The aim is to produce high quality data that can be used in metrology applications. The issue of Integrated Sensor Orientation (ISO) of camera poses using only GPS measurements is presented and discussed. The accuracy reached by our system based on sensors developed at the French Mapping Agency (IGN) Opto-Electronics, Instrumentation and Metrology Laboratory (LOEMI) is qualified. These sensors are specially designed for close-range aerial image acquisition with a UAV. Lever-arm calibration and time synchronization are explained and performed to reach maximum accuracy. All processing steps are detailed from data acquisition to quality control of final products. We show that an accuracy of a few centimeters can be reached with this system which uses low-cost UAV and GPS module coupled with the IGN-LOEMI home-made camera.

  8. Time-Dependent Noise in GPS Position Time Series By a Network Noise Estimator

    Science.gov (United States)

    Dmitrieva, K.; Segall, P.

    2014-12-01

    Some current estimates of GPS velocity uncertainties for continuous stations with more than a decade of data can be very low, noise, such as random walk. Traditional estimators, based on individual time series, are insensitive to low amplitude random walk, yet such noise significantly increases GPS velocity uncertainties. We develop a new approach to estimating noise in GPS time series, focusing on areas where the signal in the data is well characterized. We analyze data from the seismically inactive parts of central US. The data is decomposed into signal, plate rotation and Glacial Isostatic Adjustment (GIA), and various noise components. Our method processes multiple stations simultaneously with a Kalman Filter, and estimates average noise components for the network by maximum likelihood. Currently, we model white noise, flicker noise and random walk. Synthetic tests show that this approach correctly estimates the velocity uncertainty by determining a good estimate of random walk variance, even when it is too small to be correctly estimated by traditional approaches. We present preliminary results from a network of 15 GPS stations in the central USA. The data is in a North America fixed reference frame, we subtract seasonal components and GIA displacements used in the SNARF model. Hence, all data in this reference frame is treated as noise. We estimate random walk of 0.82 mm/yr0.5, flicker noise of 3.96 mm/yr0.25 and white noise of 1.05 mm. From these noise parameters the estimated velocity uncertainty is 0.29 mm/yr for 10 years of daily data. This uncertainty is significantly greater than estimated by the traditional methods, at 0.12 mm/yr. The estimated uncertainty is still less than the median residual velocity in the North America fixed reference frame, which could indicate that the true uncertainties are even larger. Additionally we estimated noise parameters and velocity uncertainties for the vertical component and for the data with common-mode signal

  9. Development and Positioning Accuracy Assessment of Single-Frequency Precise Point Positioning Algorithms by Combining GPS Code-Pseudorange Measurements with Real-Time SSR Corrections

    Directory of Open Access Journals (Sweden)

    Miso Kim

    2017-06-01

    Full Text Available We have developed a suite of real-time precise point positioning programs to process GPS pseudorange observables, and validated their performance through static and kinematic positioning tests. To correct inaccurate broadcast orbits and clocks, and account for signal delays occurring from the ionosphere and troposphere, we applied State Space Representation (SSR error corrections provided by the Seoul Broadcasting System (SBS in South Korea. Site displacements due to solid earth tide loading are also considered for the purpose of improving the positioning accuracy, particularly in the height direction. When the developed algorithm was tested under static positioning, Kalman-filtered solutions produced a root-mean-square error (RMSE of 0.32 and 0.40 m in the horizontal and vertical directions, respectively. For the moving platform, the RMSE was found to be 0.53 and 0.69 m in the horizontal and vertical directions.

  10. An investigation into the performance of real-time GPS+GLONASS Precise Point Positioning (PPP) in New Zealand

    Science.gov (United States)

    Harima, Ken; Choy, Suelynn; Rizos, Chris; Kogure, Satoshi

    2017-09-01

    This paper presents an investigation into the performance of real-time Global Navigation Satellite Systems (GNSS) Precise Point Positioning (PPP) in New Zealand. The motivation of the research is to evaluate the feasibility of using PPP technique and a satellite based augmentation system such as the Japanese Quasi-Zenith Satellite System (QZSS) to deliver a real-time precise positioning solution in support of a nation-wide high accuracy GNSS positioning coverage in New Zealand. Two IGS real-time correction streams are evaluated alongside with the PPP correction messages transmitted by the QZSS satellite known as MDC1. MDC1 corrections stream is generated by Japan Aerospace Exploration Agency (JAXA) using the Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis (MADOCA) software and are currently transmitted in test mode by the QZSS satellite. The IGS real-time streams are the CLK9B real-time corrections stream generated by the French Centre National D'études Spatiales (CNES) using the PPP-Wizard software, and the CLK81 real-time corrections stream produced by GMV using their MagicGNSS software. GNSS data is collected from six New Zealand CORS stations operated by Land Information New Zealand (LINZ) over a one-week period in 2015. GPS and GLONASS measurements are processed in a real-time PPP mode using the satellite orbit and clock corrections from the real-time streams. The results show that positioning accuracies of 6 cm in horizontal component and 15 cm in vertical component can be achieved in real-time PPP. The real-time GPS+GLONASS PPP solution required 30 minutes to converge to within 10 cm horizontal positioning accuracy.

  11. Characteristics of sub-daily precipitation extremes in observed data and regional climate model simulations

    Czech Academy of Sciences Publication Activity Database

    Beranová, Romana; Kyselý, Jan; Hanel, M.

    in press (2017) ISSN 0177-798X R&D Projects: GA ČR(CZ) GA14-18675S Institutional support: RVO:68378289 Keywords : sub-daily precipitation * regional climate models * extremes * Czech Republic Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 2.640, year: 2016 https://link.springer.com/article/10.1007/s00704-017-2102-0

  12. Sub-daily extreme events distribution and changes in Northeastern Brazil in the 20th century

    Directory of Open Access Journals (Sweden)

    R. Basso

    2015-06-01

    Full Text Available The regional analysis of extreme hydrological events is connected with the availability of a dense network of rainfall data that is absent or inaccessible in Brazil, especially for sub-daily information. In engineering, extreme events rainfall information is represented by intensity–duration–frequency (IDF relationships which are the most commonly used tools in water resources engineering for planning and design. Even if the sub-daily information that is included in the relationships is not available, the extreme rainfall information rest in the fundamentals of the IDF. This paper analyzes spatial distribution and track changes in sub-daily precipitation over Northeastern (NE Brazil. Precipitation was estimated from IDF relationships information in Brazil based in rainfall measured from 1920's to 1950's (but still used in engineering projects and information from the last half of the 20th century obtained from several IDFs gathered from municipalities' manuals, local symposia and books in many cases not easily obtainable. Results showed an intensification of extreme events in recent years, especially in shorter duration rainfall (less than 12 h. Hourly rainfall is bigger in almost all the Brazilian region, but especially in littoral and Northern portion, however, 12 and 24 h rainfall exhibit increases in the North, but, lower values in the Southern half of the region in concordance with flood changes reported by Milly et al. (2005. Analyzing the ratio between 1 and 24 h rainfall is possible to confirm its increase in all the region, with up to 35% in some areas. These results were able to show insight of sub-daily extreme events changes during 20th century in NE Brazil were previous reports were not found. The results also alerts for the necessity of engineering projects review, as outdated information is still being used for design purposes.

  13. Precise positioning with current multi-constellation Global Navigation Satellite Systems: GPS, GLONASS, Galileo and BeiDou.

    Science.gov (United States)

    Li, Xingxing; Zhang, Xiaohong; Ren, Xiaodong; Fritsche, Mathias; Wickert, Jens; Schuh, Harald

    2015-02-09

    The world of satellite navigation is undergoing dramatic changes with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs). At the moment more than 70 satellites are already in view, and about 120 satellites will be available once all four systems (BeiDou + Galileo + GLONASS + GPS) are fully deployed in the next few years. This will bring great opportunities and challenges for both scientific and engineering applications. In this paper we develop a four-system positioning model to make full use of all available observations from different GNSSs. The significant improvement of satellite visibility, spatial geometry, dilution of precision, convergence, accuracy, continuity and reliability that a combining utilization of multi-GNSS brings to precise positioning are carefully analyzed and evaluated, especially in constrained environments.

  14. A comparison of methods to estimate future sub-daily design rainfall

    Science.gov (United States)

    Li, J.; Johnson, F.; Evans, J.; Sharma, A.

    2017-12-01

    Warmer temperatures are expected to increase extreme short-duration rainfall due to the increased moisture-holding capacity of the atmosphere. While attention has been paid to the impacts of climate change on future design rainfalls at daily or longer time scales, the potential changes in short duration design rainfalls have been often overlooked due to the limited availability of sub-daily projections and observations. This study uses a high-resolution regional climate model (RCM) to predict the changes in sub-daily design rainfalls for the Greater Sydney region in Australia. Sixteen methods for predicting changes to sub-daily future extremes are assessed based on different options for bias correction, disaggregation and frequency analysis. A Monte Carlo cross-validation procedure is employed to evaluate the skill of each method in estimating the design rainfall for the current climate. It is found that bias correction significantly improves the accuracy of the design rainfall estimated for the current climate. For 1 h events, bias correcting the hourly annual maximum rainfall simulated by the RCM produces design rainfall closest to observations, whereas for multi-hour events, disaggregating the daily rainfall total is recommended. This suggests that the RCM fails to simulate the observed multi-duration rainfall persistence, which is a common issue for most climate models. Despite the significant differences in the estimated design rainfalls between different methods, all methods lead to an increase in design rainfalls across the majority of the study region.

  15. Investigation for improving Global Positioning System (GPS) orbits using a discrete sequential estimator and stochastic models of selected physical processes

    Science.gov (United States)

    Goad, Clyde C.; Chadwell, C. David

    1993-01-01

    GEODYNII is a conventional batch least-squares differential corrector computer program with deterministic models of the physical environment. Conventional algorithms were used to process differenced phase and pseudorange data to determine eight-day Global Positioning system (GPS) orbits with several meter accuracy. However, random physical processes drive the errors whose magnitudes prevent improving the GPS orbit accuracy. To improve the orbit accuracy, these random processes should be modeled stochastically. The conventional batch least-squares algorithm cannot accommodate stochastic models, only a stochastic estimation algorithm is suitable, such as a sequential filter/smoother. Also, GEODYNII cannot currently model the correlation among data values. Differenced pseudorange, and especially differenced phase, are precise data types that can be used to improve the GPS orbit precision. To overcome these limitations and improve the accuracy of GPS orbits computed using GEODYNII, we proposed to develop a sequential stochastic filter/smoother processor by using GEODYNII as a type of trajectory preprocessor. Our proposed processor is now completed. It contains a correlated double difference range processing capability, first order Gauss Markov models for the solar radiation pressure scale coefficient and y-bias acceleration, and a random walk model for the tropospheric refraction correction. The development approach was to interface the standard GEODYNII output files (measurement partials and variationals) with software modules containing the stochastic estimator, the stochastic models, and a double differenced phase range processing routine. Thus, no modifications to the original GEODYNII software were required. A schematic of the development is shown. The observational data are edited in the preprocessor and the data are passed to GEODYNII as one of its standard data types. A reference orbit is determined using GEODYNII as a batch least-squares processor and the

  16. GPS Test Facility

    Data.gov (United States)

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

  17. Impact of habitat-specific GPS positional error on detection of movement scales by first-passage time analysis.

    Directory of Open Access Journals (Sweden)

    David M Williams

    Full Text Available Advances in animal tracking technologies have reduced but not eliminated positional error. While aware of such inherent error, scientists often proceed with analyses that assume exact locations. The results of such analyses then represent one realization in a distribution of possible outcomes. Evaluating results within the context of that distribution can strengthen or weaken our confidence in conclusions drawn from the analysis in question. We evaluated the habitat-specific positional error of stationary GPS collars placed under a range of vegetation conditions that produced a gradient of canopy cover. We explored how variation of positional error in different vegetation cover types affects a researcher's ability to discern scales of movement in analyses of first-passage time for white-tailed deer (Odocoileus virginianus. We placed 11 GPS collars in 4 different vegetative canopy cover types classified as the proportion of cover above the collar (0-25%, 26-50%, 51-75%, and 76-100%. We simulated the effect of positional error on individual movement paths using cover-specific error distributions at each location. The different cover classes did not introduce any directional bias in positional observations (1 m≤mean≤6.51 m, 0.24≤p≤0.47, but the standard deviation of positional error of fixes increased significantly with increasing canopy cover class for the 0-25%, 26-50%, 51-75% classes (SD = 2.18 m, 3.07 m, and 4.61 m, respectively and then leveled off in the 76-100% cover class (SD = 4.43 m. We then added cover-specific positional errors to individual deer movement paths and conducted first-passage time analyses on the noisy and original paths. First-passage time analyses were robust to habitat-specific error in a forest-agriculture landscape. For deer in a fragmented forest-agriculture environment, and species that move across similar geographic extents, we suggest that first-passage time analysis is robust with regard to

  18. Application of Individualized Speed Thresholds to Interpret Position Specific Running Demands in Elite Professional Rugby Union: A GPS Study.

    Directory of Open Access Journals (Sweden)

    Cillian Reardon

    Full Text Available A number of studies have used GPS technology to categorise rugby union locomotive demands. However, the utility of the results of these studies is confounded by small sample sizes, sub-elite player status and the global application of absolute speed thresholds to all player positions. Furthermore, many of these studies have used GPS units with low sampling frequencies. The aim of the present study was to compare and contrast the high speed running (HSR demands of professional rugby union when utilizing micro-technology units sampling at 10 Hz and applying relative or individualised speed zones. The results of this study indicate that application of individualised speed zones results in a significant shift in the interpretation of the HSR demands of both forwards and backs and positional sub-categories therein. When considering the use of an absolute in comparison to an individualised HSR threshold, there was a significant underestimation for forwards of HSR distance (HSRD (absolute = 269 ± 172.02, individualised = 354.72 ± 99.22, p < 0.001, HSR% (absolute = 5.15 ± 3.18, individualised = 7.06 ± 2.48, p < 0.001 and HSR efforts (HSRE (absolute = 18.81 ± 12.25; individualised = 24.78 ± 8.30, p < 0.001. In contrast, there was a significant overestimation of the same HSR metrics for backs with the use of an absolute threshold (HSRD absolute = 697.79 ± 198.11, individualised = 570.02 ± 171.14, p < 0.001; HSR% absolute = 10.85 ± 2.82, individualised = 8.95 ± 2.76, p < 0.001; HSRE absolute = 41.55 ± 11.25; individualised = 34.54 ± 9.24, p < 0.001. This under- or overestimation associated with an absolute speed zone applies to varying degrees across the ten positional sub-categories analyzed and also to individuals within the same positional sub-category. The results of the present study indicated that although use of an individulised HSR threshold improves the interpretation of the HSR demands on a positional basis, inter

  19. A resampling strategy based on bootstrap to reduce the effect of large blunders in GPS absolute positioning

    Science.gov (United States)

    Angrisano, Antonio; Maratea, Antonio; Gaglione, Salvatore

    2017-07-01

    In the absence of obstacles, a GPS device is generally able to provide continuous and accurate estimates of position, while in urban scenarios buildings can generate multipath and echo-only phenomena that severely affect the continuity and the accuracy of the provided estimates. Receiver autonomous integrity monitoring (RAIM) techniques are able to reduce the negative consequences of large blunders in urban scenarios, but require both a good redundancy and a low contamination to be effective. In this paper a resampling strategy based on bootstrap is proposed as an alternative to RAIM, in order to estimate accurately position in case of low redundancy and multiple blunders: starting with the pseudorange measurement model, at each epoch the available measurements are bootstrapped—that is random sampled with replacement—and the generated a posteriori empirical distribution is exploited to derive the final position. Compared to standard bootstrap, in this paper the sampling probabilities are not uniform, but vary according to an indicator of the measurement quality. The proposed method has been compared with two different RAIM techniques on a data set collected in critical conditions, resulting in a clear improvement on all considered figures of merit.

  20. Evapotranspiration partition at sub-daily scale using laser and chamber techniques

    Science.gov (United States)

    Wang, L.; Parkes, S. D.; McCabe, M. F.; Azcurra, C.; Wang, J.

    2012-12-01

    Evapotranspiration (ET) partitioning is important for quantifying the water budget and understanding vegetation control on water cycles in various ecosystems. With the development of spectroscopy-based techniques for in-situ isotope measurements, the use of stable isotope based ET partition is rising rapidly. The sub-daily scale ET partition, however, is still rarely seen in the literature. In this study, we conducted an intensive field campaign measuring ET partition using laser-based isotope and chamber techniques in a pasture system between May and June 2012 in eastern Australia. Six soil collars were used, three of which had natural vegetation and the other three were bare soil collars where vegetation was artificially removed. The vegetated and bare soil collars were used to determine the isotopic composition of ET and evaporation, respectively. The isotopic composition of the transpiration flux was determined using a Licor leaf chamber for grasses inside the vegetated collars. The diurnal patterns in isotopic compositions were observed. In the morning, the isotopic compositions were depleted. The isotopic composition of ET became more enriched and leveled off during midday. Similar patterns were found for the isotopic composition of evaporation. Overall the total ET flux over the campaign was dominated by evaporation, though transpiration contributions were high between 10am and 12pm. This study demonstrated the use of chamber-based measurements for direct partitioning of ET at sub-daily scale and showed a rarely observed diurnal pattern of ET partition.

  1. Global Positioning System (GPS) and Geographic Information System (GIS) analysis of mobile harvesting equipment and sediment delivery to streams during forest harvest operations on steep terrain: Experimental design

    Science.gov (United States)

    Daniel Bowker; Jeff Stringer; Chris Barton; Songlin. Fei

    2011-01-01

    Sediment mobilized by forest harvest machine traffic contributes substantially to the degradation of headwater stream systems. This study monitored forest harvest machine traffic to analyze how it affects sediment delivery to stream channels. Harvest machines were outfitted with global positioning system (GPS) dataloggers, recording machine movements and working status...

  2. Sub-daily precipitation disaggregation for a simulation of annual runoff maxima

    Science.gov (United States)

    Sikorska, Anna; Seibert, Jan

    2017-04-01

    Measurement of precipitation has been often restricted to daily totals only. This applies especially to observations from the previous century which constitutes a valuable source of long-term precipitation records needed for statistical analysis such as for annual runoff maxima. In this respect, the knowledge about the exact temporal distribution of these precipitation totals at sub-daily time steps can play an important role on the magnitude of simulated runoff maxima using these data. But it is difficult to estimate the sub-daily temporal distribution of precipitation if it was not measured. Instead, the effect of the precipitation in the form of runoff measured at the catchment outlet, which is usually available at sub-daily time steps for longer periods, provides an alternative to evaluate the potential effect of the need to disaggregate precipitation data. In this study we assess how the choice of the temporal distribution of daily precipitation totals might affect the simulation of the catchment runoff annual maxima when using a hydrological model. To examine this issue, we tested six different settings of precipitation total distribution within the day. These are: 1) uniform distribution (daily totals uniquely divided over 24 hours); all daily totals fall within a respective time window, i.e., 2) one hour, 3) two successive hours, 4) three successive hours, 5) six successive hours, and 6) twelve successive hours, each time randomly selected for each observation day independently. To assess the effect on simulated runoff maxima, such generated hourly precipitation datasets were next used as input into a pre-calibrated HBV model. As a reference, we used model simulations with observed hourly precipitation data. This study was conducted using thirty years of precipitation and runoff observations in three Swiss catchments. Our results showed that the annual maxima were best simulated when distributing daily totals over twelve successive hours randomly selected

  3. Non-stationarity in daily and sub-daily intense rainfall – Part 1: Sydney, Australia

    Directory of Open Access Journals (Sweden)

    D. Jakob

    2011-08-01

    Full Text Available This study was driven by a need to clarify how variations in climate might affect intense rainfall and the potential for flooding. Sub-daily durations are of particular interest for urban applications. Worldwide, few such observation-based studies exist, which is mainly due to limitations in data. While there are still large discrepancies between precipitation data sets from observations and models, both show that there is a tendency for moist regions to become wetter and for dry regions to become drier. However, changes in extreme conditions may show the opposite sign to those in average conditions. Where changes in observed intense precipitation have been studied, this has typically been for daily durations or longer.

    The purpose of this two-part study is to examine daily and sub-daily rainfall extremes for evidence of non-stationarity. Here the problem was addressed by supplementing one long record (Part 1 by a set of shorter records for a 30-yr concurrent period (Part 2. Variations in frequency and magnitude of rainfall extremes across durations from 6 min to 72 h were assessed using data from sites in the south-east of Australia. For the analyses presented in this paper, a peaks-over-threshold approach was chosen since it allows investigating changes in frequency as well as magnitude. Non-parametric approaches were used to assess changes in frequency, magnitude, and quantile estimates as well as the statistical significance of changes for one station (Sydney Observatory Hill for the period 1921 to 2005. Deviations from the long-term average vary with season, duration, and threshold. The effects of climate variations are most readily detected for the highest thresholds. Deviations from the long-term average tend to be larger for frequencies than for magnitudes, and changes in frequency and magnitude may have opposite signs.

    Investigations presented in this paper show that variations in frequency and magnitude of events at

  4. GPS satellite clock error estimation for real time PPP and the assessment of position quality

    Science.gov (United States)

    Galera Monico, J. F.; Marques, H. A.

    2012-12-01

    Real time PPP method requires the availability of real time precise orbits and corrections or errors of the satellites clocks. Currently, it is possible to use the predicted IGU ephemerides available by the IGS centers. However, the satellites clocks corrections available in the IGU do not present enough accuracy (3 ns or 0.9 m) to accomplish real time PPP with centimeter accuracy. Therefore, it is necessary to develop appropriate methodologies for estimating the satellite clock corrections in real time with better quality. The estimation of satellite clock corrections can be carried out based on a GNSS network of reference and performing the adjustment in a combined PPP mode. Thus, all systematic effects involved with the GNSS satellite signals must be modeled appropriately for each station of the network. Once the corrections of the satellite clocks are estimated in real time, they should be sent to the users, which will use them for application in the GNSS data processing from a particular station also in real time PPP mode. To achieve such aim, a system composed by two software's, one for estimating the satellite clock corrections based on data from a GNSS network and the other for the realization of the real time PPP was developed. The results were generated in real time and post-processed mode (simulating real time). The estimate of the satellites clocks corrections was generated based on the measurements of the pseudorange smoothed by carrier phase and also using the original pseudorange and carrier phase with ambiguities estimation for each satellite available at each station. The daily accuracy of the estimated satellite clock corrections reached the order of 0.15 ns (0,05 m) and the application in the GNSS positioning shows that is possible now to accomplish real time PPP in the kinematic mode with accuracy of the order of 10 to 20 cm.

  5. Strengths and weaknesses of Global Positioning System (GPS) data-loggers and semi-structured interviews for capturing fine-scale human mobility: findings from Iquitos, Peru.

    Science.gov (United States)

    Paz-Soldan, Valerie A; Reiner, Robert C; Morrison, Amy C; Stoddard, Steven T; Kitron, Uriel; Scott, Thomas W; Elder, John P; Halsey, Eric S; Kochel, Tadeusz J; Astete, Helvio; Vazquez-Prokopec, Gonzalo M

    2014-06-01

    Quantifying human mobility has significant consequences for studying physical activity, exposure to pathogens, and generating more realistic infectious disease models. Location-aware technologies such as Global Positioning System (GPS)-enabled devices are used increasingly as a gold standard for mobility research. The main goal of this observational study was to compare and contrast the information obtained through GPS and semi-structured interviews (SSI) to assess issues affecting data quality and, ultimately, our ability to measure fine-scale human mobility. A total of 160 individuals, ages 7 to 74, from Iquitos, Peru, were tracked using GPS data-loggers for 14 days and later interviewed using the SSI about places they visited while tracked. A total of 2,047 and 886 places were reported in the SSI and identified by GPS, respectively. Differences in the concordance between methods occurred by location type, distance threshold (within a given radius to be considered a match) selected, GPS data collection frequency (i.e., 30, 90 or 150 seconds) and number of GPS points near the SSI place considered to define a match. Both methods had perfect concordance identifying each participant's house, followed by 80-100% concordance for identifying schools and lodgings, and 50-80% concordance for residences and commercial and religious locations. As the distance threshold selected increased, the concordance between SSI and raw GPS data increased (beyond 20 meters most locations reached their maximum concordance). Processing raw GPS data using a signal-clustering algorithm decreased overall concordance to 14.3%. The most common causes of discordance as described by a sub-sample (n=101) with whom we followed-up were GPS units being accidentally off (30%), forgetting or purposely not taking the units when leaving home (24.8%), possible barriers to the signal (4.7%) and leaving units home to recharge (4.6%). We provide a quantitative assessment of the strengths and weaknesses of

  6. From GSM positioning to the identification of multiple spherical magma sources using GPS data: the TOPINV algorithm and software

    Science.gov (United States)

    Saltogianni, Vasso; Stiros, Stathis

    2014-05-01

    Inversion of spherical (Mogi) multiple magma sources from surface deformation data is a very difficult task because it corresponds to the inversion of a redundant, highly non-linear system of equations, and is usually faced in the basis of sampling techniques (up to 104-106 Monte Carlo-based samples). An alternative, quasi-deterministic topological inversion based on the principles of beacon or GSM positioning has been proposed to solve this problem: the location of a point is determined from the common surface (intersection of geometric loci) of the areas covered by a beacon/GSM cell, using simple forward computations only. Our approach is exemplified in the solution of a system of n equations and two unknowns (x,y). First, a 2D grid G is defined with all possible locations of (x,y) approximated by individual points. Second, for each measurement/observation i a simple inequality is formed; this inequality defines that the (forward) predicted value for a point of the grid minus the observed value is in absolute value smaller than a factor ktimes the standard error of the measurement. Grid G is 'scanned' with this inequality and subset Si of its points which satisfy this inequality (Boolean operation) is defined. The process is repeated for all n observations and n subsets Si are defined. Third, the common section S of these subsets Si, if there exists, contains the solution of the system, and an estimate of this solution is derived as the center of gravity of S. Fourth, the solution is optimized repeating this process for various values of k, until a minimal value of S and a minimum variance of the solution is obtained. This approach can be generalized for n unknown variables, leading to a grid G in Rn space, R4for a single Mogi source and R8 for a double one. Techniques to focus on unique, statistically significant solutions (especially minimal trade-off between depth and volume of modeled sources) and to calculations limited to less than 109 gridpoints are

  7. IceBridge GPS L1B Time-Tagged Real-Time Position and Attitude Solution, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains elevation, roll, pitch, and heading measurements over Antarctica using the Ashtech GG24 GPS+ receiver and the Systron and Donner MMQ-50...

  8. IceBridge GPS L1B Time-Tagged Real-Time Position and Attitude Solution

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains elevation, roll, pitch, and heading measurements over Antarctica using the Ashtech GG24 GPS+ receiver and the Systron and Donner MMQ-50...

  9. Combination of radar and daily precipitation data to estimate meaningful sub-daily point precipitation extremes

    Science.gov (United States)

    Pegram, Geoff; Bardossy, Andras; Sinclair, Scott

    2017-04-01

    The use of radar measurements for the space time estimation of precipitation has for many decades been a central topic in hydro-meteorology. In this presentation we are interested specifically in daily and sub-daily extreme values of precipitation at gauged or ungauged locations which are important for design. The purpose of the presentation is to develop a methodology to combine daily precipitation observations and radar measurements to estimate sub-daily extremes at point locations. Radar data corrected using precipitation-reflectivity relationships lead to biased estimations of extremes. Different possibilities of correcting systematic errors using the daily observations are investigated. Observed gauged daily amounts are interpolated to un-sampled points and subsequently disaggregated using the sub-daily values obtained by the radar. Different corrections based on the spatial variability and the sub-daily entropy of scaled rainfall distributions are used to provide unbiased corrections of short duration extremes. In addition, a statistical procedure not based on a matching day by day correction is tested. In this last procedure, as we are only interested in rare extremes, low to medium values of rainfall depth were neglected leaving 12 days of ranked daily maxima in each set per year, whose sum typically comprises about 50% of each annual rainfall total. The sum of these 12 day maxima is first interpolated using a Kriging procedure. Subsequently this sum is disaggregated to daily values using a nearest neighbour procedure. The daily sums are then disaggregated by using the relative values of the biggest 12 radar based days in each year. Of course, the timings of radar and gauge maxima can be different, so the new method presented here uses radar for disaggregating daily gauge totals down to 15 min intervals in order to extract the maxima of sub-hourly through to daily rainfall. The methodologies were tested in South Africa, where an S-band radar operated

  10. Regional frequency analysis of observed sub-daily rainfall maxima over eastern China

    Science.gov (United States)

    Sun, Hemin; Wang, Guojie; Li, Xiucang; Chen, Jing; Su, Buda; Jiang, Tong

    2017-02-01

    Based on hourly rainfall observational data from 442 stations during 1960-2014, a regional frequency analysis of the annual maxima (AM) sub-daily rainfall series (1-, 2-, 3-, 6-, 12-, and 24-h rainfall, using a moving window approach) for eastern China was conducted. Eastern China was divided into 13 homogeneous regions: Northeast (NE1, NE2), Central (C), Central North (CN1, CN2), Central East (CE1, CE2, CE3), Southeast (SE1, SE2, SE3, SE4), and Southwest (SW). The generalized extreme value performed best for the AM series in regions NE, C, CN2, CE1, CE2, SE2, and SW, and the generalized logistic distribution was appropriate in the other regions. Maximum return levels were in the SE4 region, with value ranges of 80-270 mm (1-h to 24-h rainfall) and 108-390 mm (1-h to 24-h rainfall) for 20- and 100 yr, respectively. Minimum return levels were in the CN1 and NE1 regions, with values of 37-104 mm and 53-140 mm for 20 and 100 yr, respectively. Comparing return levels using the optimal and commonly used Pearson-III distribution, the mean return-level differences in eastern China for 1-24-h rainfall varied from -3-4 mm to -23-11 mm (-10%-10%) for 20-yr events, reaching -6-26 mm (-10%-30%) and -10-133 mm (-10%-90%) for 100-yr events. In view of the large differences in estimated return levels, more attention should be given to frequency analysis of sub-daily rainfall over China, for improved water management and disaster reduction.

  11. GPS Separator

    CERN Multimedia

    2016-01-01

    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.

  12. Hacking GPS

    CERN Document Server

    Kingsley-Hughes, Kathie

    2005-01-01

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

  13. PEMODELAN PROTOTYPE TRACKING DENGAN PEMANFAATAN GEOLOCATION SEBAGAI GPS (GLOBAL POSITIONING SYSTEM BERBASIS WEB MOBILE PADA JASA PENGIRIMAN JNE SEMARANG

    Directory of Open Access Journals (Sweden)

    Ika Tri Meilani

    2016-03-01

    Full Text Available JNE merupakan perusahaan yang bergerak dibidang pengiriman barang atau dokumen yang sangat maju, karena banyak dimanfaatkan berbagai toko online dalam melakukan pengiriman barang pada customer. Sementara itu, tingkat kejahatan dijalanan semakin meningkat di berbagai kota di Indonesia. Sehingga diperlukan antisipasi pengamanan pada sebuah pengiriman untuk meningkatkan kepercayaan customer dan memberi rasa aman pada bagian pengangkutan. Selain dari sisi pengamanan, tingkat efisiensi waktu dalam pengiriman dapat berpengaruh pada tingkat kinerja perusahaan. Maka diperlukan sebuah sistem yang mampu memonitoring pengangkutan dan melakukan estimasi waktu secara efisien dalam membatasi waktu pengiriman dengan memanfaatkan geolocation sebagai GPS dengan menggunakan metode prototype model. Maka dapat diambil kesimpulan bahwa Pemodelan Prototype Tracking dengan Pemanfaat Geolocation sebagai GPS dapat dimanfaatkan sebagai media dalam memonitor pengiriman barang secara visual (Map. Kata Kunci : Tracking, Jasa Pengiriman, Geolocation, Google Map, GPS.

  14. Vibrations of an ice-tongue using GPS records

    Science.gov (United States)

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

    2010-05-01

    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

  15. High rate GPS positioning , JASON altimetry and marine gravimetry : monitoring the Antarctic Circumpolar Current (ACC) through the DRAKE campaigns.

    Science.gov (United States)

    Melachroinos, S. A.; Biancale, R.; Menard, Y.; Sarrailh, M.

    2008-12-01

    The Drake campaign which took place from Jan 14, 2006 - 08 Feb, 2006 has been a very successful mission in collecting a wide range of GPS and marine gravity data all along JASON altimetry ground track n° 104. The same campaign will be repeated in 2009 along 028 and 104 JASON-2 ground track. The Drake Passage (DP) chokepoint is not only well suited geographically, as the Antarctic Circumpolar Current (ACC) is constricted to its narrowest extent of 700 km, but observations and models suggest that dynamical balances are particular effective in this area. Furthermore the space geodesy observations and their products provided from several altimetry missions (currently operating ENVISAT, JASON 1 and 2, GFO, ERS and other plannified for the future such as Altika, SWOT) require the cross comparison with independent geodetic techniques at the DP. The current experiment comprises a kinematic GPS and marine gravimetry Cal/Val geodetic approach and it aims to : validate with respect to altimetry data and surface models such a kinematic high frequency GPS technique for measuring sea state and sea surface height (SSH), compare the GPS SSH profiles with altimetry mean dynamic topography (MDT) and mean sea surface (MSS) models, give recommendations for future "offshore" Cal/Val activities on the ground tracks of altimeter satellites such as JASON-2, GFO, Altika using the GNSS technology etc. The GPS observations are collected from GPS antennas installed on a wave-rider buoy , aboard the R/V "Polarstern" and from continuous geodetic reference stations in the proximity. We also analyse problems related to the ship's attitude variations in roll, pitch and yaw and a way to correct them. We also give emphasis on the impact of the ship's acceleration profiles on the so called "squat effect" and ways to deal with it. The project will in particular benefit the GOCE mission by proposing to integrate GOCE in the ocean circulation study and validate GOCE products with our independent

  16. Combining Radar and Daily Precipitation Data to Estimate Meaningful Sub-daily Precipitation Extremes

    Science.gov (United States)

    Pegram, G. G. S.; Bardossy, A.

    2016-12-01

    Short duration extreme rainfalls are important for design. The purpose of this presentation is not to improve the day by day estimation of precipitation, but to obtain reasonable statistics for the subdaily extremes at gauge locations. We are interested specifically in daily and sub-daily extreme values of precipitation at gauge locations. We do not employ the common procedure of using time series of control station to determine the missing data values in a target. We are interested in individual rare events, not sequences. The idea is to use radar to disaggregate daily totals to sub-daily amounts. In South Arica, an S-band radar operated relatively continuously at Bethlehem from 1998 to 2003, whose scan at 1.5 km above ground [CAPPI] overlapped a dense (10 km spacing) set of 45 pluviometers recording in the same 6-year period. Using this valuable set of data, we are only interested in rare extremes, therefore small to medium values of rainfall depth were neglected, leaving 12 days of ranked daily maxima in each set per year, whose sum typically comprised about 50% of each annual rainfall total. The method presented here uses radar for disaggregating daily gauge totals in subdaily intervals down to 15 minutes in order to extract the maxima of sub-hourly through to daily rainfall at each of 37 selected radar pixels [1 km square in plan] which contained one of the 45 pluviometers not masked out by the radar foot-print. The pluviometer data were aggregated to daily totals, to act as if they were daily read gauges; their only other task was to help in the cross-validation exercise. The extrema were obtained as quantiles by ordering the 12 daily maxima of each interval per year. The unusual and novel goal was not to obtain the reproduction of the precipitation matching in space and time, but to obtain frequency distributions of the gauge and radar extremes, by matching their ranks, which we found to be stable and meaningful in cross-validation tests. We provide and

  17. Assessment of long-range kinematic GPS positioning errors by comparison with airborne laser altimetry and satellite altimetry

    DEFF Research Database (Denmark)

    Zhang, X.H.; Forsberg, René

    2007-01-01

    Long-range airborne laser altimetry and laser scanning (LIDAR) or airborne gravity surveys in, for example, polar or oceanic areas require airborne kinematic GPS baselines of many hundreds of kilometers in length. In such instances, with the complications of ionospheric biases, it can be a real c...

  18. Expanding HadISD: quality-controlled, sub-daily station data from 1931

    Science.gov (United States)

    Dunn, Robert J. H.; Willett, Kate M.; Parker, David E.; Mitchell, Lorna

    2016-09-01

    HadISD is a sub-daily, station-based, quality-controlled dataset designed to study past extremes of temperature, pressure and humidity and allow comparisons to future projections. Herein we describe the first major update to the HadISD dataset. The temporal coverage of the dataset has been extended to 1931 to present, doubling the time range over which data are provided. Improvements made to the station selection and merging procedures result in 7677 stations being provided in version 2.0.0.2015p of this dataset. The selection of stations to merge together making composites has also been improved and made more robust. The underlying structure of the quality control procedure is the same as for HadISD.1.0.x, but a number of improvements have been implemented in individual tests. Also, more detailed quality control tests for wind speed and direction have been added. The data will be made available as NetCDF files at http://www.metoffice.gov.uk/hadobs/hadisd and updated annually.

  19. Using Global Positioning Systems (GPS) and temperature data to generate time-activity classifications for estimating personal exposure in air monitoring studies: an automated method.

    Science.gov (United States)

    Nethery, Elizabeth; Mallach, Gary; Rainham, Daniel; Goldberg, Mark S; Wheeler, Amanda J

    2014-05-08

    Personal exposure studies of air pollution generally use self-reported diaries to capture individuals' time-activity data. Enhancements in the accuracy, size, memory and battery life of personal Global Positioning Systems (GPS) units have allowed for higher resolution tracking of study participants' locations. Improved time-activity classifications combined with personal continuous air pollution sampling can improve assessments of location-related air pollution exposures for health studies. Data was collected using a GPS and personal temperature from 54 children with asthma living in Montreal, Canada, who participated in a 10-day personal air pollution exposure study. A method was developed that incorporated personal temperature data and then matched a participant's position against available spatial data (i.e., road networks) to generate time-activity categories. The diary-based and GPS-generated time-activity categories were compared and combined with continuous personal PM2.5 data to assess the impact of exposure misclassification when using diary-based methods. There was good agreement between the automated method and the diary method; however, the automated method (means: outdoors = 5.1%, indoors other =9.8%) estimated less time spent in some locations compared to the diary method (outdoors = 6.7%, indoors other = 14.4%). Agreement statistics (AC1 = 0.778) suggest 'good' agreement between methods over all location categories. However, location categories (Outdoors and Transit) where less time is spent show greater disagreement: e.g., mean time "Indoors Other" using the time-activity diary was 14.4% compared to 9.8% using the automated method. While mean daily time "In Transit" was relatively consistent between the methods, the mean daily exposure to PM2.5 while "In Transit" was 15.9 μg/m3 using the automated method compared to 6.8 μg/m3 using the daily diary. Mean times spent in different locations as categorized by a GPS-based method were

  20. Enhancing positioning accuracy in urban terrain by fusing data from a GPS receiver, inertial sensors, stereo-camera and digital maps for pedestrian navigation.

    Science.gov (United States)

    Przemyslaw, Baranski; Pawel, Strumillo

    2012-01-01

    The paper presents an algorithm for estimating a pedestrian location in an urban environment. The algorithm is based on the particle filter and uses different data sources: a GPS receiver, inertial sensors, probability maps and a stereo camera. Inertial sensors are used to estimate a relative displacement of a pedestrian. A gyroscope estimates a change in the heading direction. An accelerometer is used to count a pedestrian's steps and their lengths. The so-called probability maps help to limit GPS inaccuracy by imposing constraints on pedestrian kinematics, e.g., it is assumed that a pedestrian cannot cross buildings, fences etc. This limits position inaccuracy to ca. 10 m. Incorporation of depth estimates derived from a stereo camera that are compared to the 3D model of an environment has enabled further reduction of positioning errors. As a result, for 90% of the time, the algorithm is able to estimate a pedestrian location with an error smaller than 2 m, compared to an error of 6.5 m for a navigation based solely on GPS.

  1. Simulating sub-daily Intensity-Frequency-Duration curves in Australia using a dynamical high-resolution regional climate model

    Science.gov (United States)

    Mantegna, Gabriel A.; White, Christopher J.; Remenyi, Tomas A.; Corney, Stuart P.; Fox-Hughes, Paul

    2017-11-01

    Climate change has the potential to significantly alter the characteristics of high-intensity, short-duration rainfall events, potentially leading to more severe and more frequent flash floods. Research has shown that future changes to such events could far exceed expectations based on temperature scaling and basic physical principles alone, but that computationally expensive convection-permitting models are required to accurately simulate sub-daily extreme rainfall events. It is therefore crucial to be able to model future changes to sub-daily duration extreme rainfall events as cost effectively as possible, especially in Australia where such information is scarce. In this study, we seek to determine what the shortest duration of extreme rainfall is that can be simulated by a less computationally expensive convection-parametrizing Regional Climate Model (RCM). We examine the ability of the Conformal Cubic Atmospheric Model (CCAM), a ∼10 km high-resolution convection-parametrizing RCM, to reproduce sub-daily Intensity-Frequency-Duration (IFD) curves corresponding to two long-term observational stations in the Australian island state of Tasmania, and examine the future model projections. We find that CCAM simulates observed extreme rainfall statistics well for 3-h durations and longer, challenging the current understanding that convection-permitting models are needed to accurately model sub-daily extreme rainfall events. Further, future projections from CCAM for the end of this Century show that extreme sub-daily rainfall intensities could increase by more than 15% per °C, far exceeding the 7% scaling estimate predicted by the Clausius-Clapeyron vapour pressure relationship and the 5% scaling estimate recommended by the Australian Rainfall and Runoff guide.

  2. Calculation of new snow densities from sub-daily automated snow measurements

    Science.gov (United States)

    Helfricht, Kay; Hartl, Lea; Koch, Roland; Marty, Christoph; Lehning, Michael; Olefs, Marc

    2017-04-01

    In mountain regions there is an increasing demand for high-quality analysis, nowcasting and short-range forecasts of the spatial distribution of snowfall. Operational services, such as for avalanche warning, road maintenance and hydrology, as well as hydropower companies and ski resorts need reliable information on the depth of new snow (HN) and the corresponding water equivalent (HNW). However, the ratio of HNW to HN can vary from 1:3 to 1:30 because of the high variability of new snow density with respect to meteorological conditions. In the past, attempts were made to calculate new snow densities from meteorological parameters mainly using daily values of temperature and wind. Further complex statistical relationships have been used to calculate new snow densities on hourly to sub-hourly time intervals to drive multi-layer snow cover models. However, only a few long-term in-situ measurements of new snow density exist for sub-daily time intervals. Settling processes within the new snow due to loading and metamorphism need to be considered when computing new snow density. As the effect of these processes is more pronounced for long time intervals, a high temporal resolution of measurements is desirable. Within the pluSnow project data of several automatic weather stations with simultaneous measurements of precipitation (pluviometers), snow water equivalent (SWE) using snow pillows and snow depth (HS) measurements using ultrasonic rangers were analysed. New snow densities were calculated for a set of data filtered on the basis of meteorological thresholds. The calculated new snow densities were compared to results from existing new snow density parameterizations. To account for effects of settling of the snow cover, a case study based on a multi-year data set using the snow cover model SNOWPACK at Weissfluhjoch was performed. Measured median values of hourly new snow densities at the different stations range from 54 to 83 kgm-3. This is considerably lower than a 1

  3. The potential for the exploration of activity patterns in the urban landscape with GPS-positioning and electronic activity diaries

    DEFF Research Database (Denmark)

    Hovgesen, Henrik Harder; Nielsen, Thomas Alexander Sick; Lassen, Claus

    2005-01-01

    The integration of GPS-devices with handheld cell phones or small computers opens new perspectives for urban and regional research. Detailed knowledge may now be gained on peoples itineraries through the urban landscape, how places are embedded in use contexts with each others and how temporal...... rythms affects the different parts of the city. GPS-based tracking has previously mainly been used to track vehicle movements, fx. in transportation surveys. The use of personal devices makes it foremost possible to place the individual respondents use of urban space in its context of transport routes...... on the use of urban space. The core of the work will be an equal treatment of activities in the virtual as well as the physical world. Substitution effects between the virtual and the physical world will be in focus, together with differences between the spatio-temporal patterns of groups with different...

  4. New ERP predictions based on (sub-)daily ocean tides from satellite altimetry data

    Science.gov (United States)

    Madzak, Matthias; Böhm, Sigrid; Böhm, Johannes; Bosch, Wolfgang; Schuh, Harald

    2013-04-01

    A new model for Earth rotation variations based on ocean tide models is highly desirable in order to close the gap between geophysical Earth rotation models and geodetic observations. We have started a project, SPOT (Short Period Ocean Tidal variations in Earth Rotation), with the goal to develop a new model of short period Earth rotation variations based on one of the best currently available empirical ocean tide models obtained from satellite altimetry. We employ the EOT11a model which is an upgrade of EOT08a, developed at DGFI, Munich. As EOT11a does not provide the tidal current velocities which are fundamental contributors to Earth rotation excitation, the calculation of current velocities from the tidal elevations is one of three main areas of research in project SPOT. The second key aspect is the conversion from ocean tidal angular momentum to the corresponding ERP variations using state-of-the-art transfer functions. A peculiar innovation at this step will be to consider the Earth's response to ocean tidal loading based on a realistic Earth model, including an anelastic mantle. The third part of the project deals with the introduction of the effect of minor tides. Ocean tide models usually only provide major semi-diurnal and diurnal tidal terms and the minor tides have to be inferred through admittance assumptions. Within the proposed project, selected minor tidal terms and the corresponding ERP variations shall be derived directly from satellite altimetry data. We determine ocean tidal angular momentum of four diurnal and five sub-daily tides from EOT11a and apply the angular momentum approach to derive a new model of ocean tidal Earth rotation variations. This poster gives a detailed description of project SPOT as well as the status of work progress. First results are presented as well.

  5. Evaluating elk habitat interactions with GPS collars

    Science.gov (United States)

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

    2001-01-01

    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...

  6. Tightly Coupled Integration of GPS Ambiguity Fixed Precise Point Positioning and MEMS-INS through a Troposphere-Constrained Adaptive Kalman Filter

    Science.gov (United States)

    Han, Houzeng; Xu, Tianhe; Wang, Jian

    2016-01-01

    Precise Point Positioning (PPP) makes use of the undifferenced pseudorange and carrier phase measurements with ionospheric-free (IF) combinations to achieve centimeter-level positioning accuracy. Conventionally, the IF ambiguities are estimated as float values. To improve the PPP positioning accuracy and shorten the convergence time, the integer phase clock model with between-satellites single-difference (BSSD) operation is used to recover the integer property. However, the continuity and availability of stand-alone PPP is largely restricted by the observation environment. The positioning performance will be significantly degraded when GPS operates under challenging environments, if less than five satellites are present. A commonly used approach is integrating a low cost inertial sensor to improve the positioning performance and robustness. In this study, a tightly coupled (TC) algorithm is implemented by integrating PPP with inertial navigation system (INS) using an Extended Kalman filter (EKF). The navigation states, inertial sensor errors and GPS error states are estimated together. The troposphere constrained approach, which utilizes external tropospheric delay as virtual observation, is applied to further improve the ambiguity-fixed height positioning accuracy, and an improved adaptive filtering strategy is implemented to improve the covariance modelling considering the realistic noise effect. A field vehicular test with a geodetic GPS receiver and a low cost inertial sensor was conducted to validate the improvement on positioning performance with the proposed approach. The results show that the positioning accuracy has been improved with inertial aiding. Centimeter-level positioning accuracy is achievable during the test, and the PPP/INS TC integration achieves a fast re-convergence after signal outages. For troposphere constrained solutions, a significant improvement for the height component has been obtained. The overall positioning accuracies of the height

  7. Tightly Coupled Integration of GPS Ambiguity Fixed Precise Point Positioning and MEMS-INS through a Troposphere-Constrained Adaptive Kalman Filter

    Directory of Open Access Journals (Sweden)

    Houzeng Han

    2016-07-01

    Full Text Available Precise Point Positioning (PPP makes use of the undifferenced pseudorange and carrier phase measurements with ionospheric-free (IF combinations to achieve centimeter-level positioning accuracy. Conventionally, the IF ambiguities are estimated as float values. To improve the PPP positioning accuracy and shorten the convergence time, the integer phase clock model with between-satellites single-difference (BSSD operation is used to recover the integer property. However, the continuity and availability of stand-alone PPP is largely restricted by the observation environment. The positioning performance will be significantly degraded when GPS operates under challenging environments, if less than five satellites are present. A commonly used approach is integrating a low cost inertial sensor to improve the positioning performance and robustness. In this study, a tightly coupled (TC algorithm is implemented by integrating PPP with inertial navigation system (INS using an Extended Kalman filter (EKF. The navigation states, inertial sensor errors and GPS error states are estimated together. The troposphere constrained approach, which utilizes external tropospheric delay as virtual observation, is applied to further improve the ambiguity-fixed height positioning accuracy, and an improved adaptive filtering strategy is implemented to improve the covariance modelling considering the realistic noise effect. A field vehicular test with a geodetic GPS receiver and a low cost inertial sensor was conducted to validate the improvement on positioning performance with the proposed approach. The results show that the positioning accuracy has been improved with inertial aiding. Centimeter-level positioning accuracy is achievable during the test, and the PPP/INS TC integration achieves a fast re-convergence after signal outages. For troposphere constrained solutions, a significant improvement for the height component has been obtained. The overall positioning accuracies

  8. Characterizing effects of hydropower plants on sub-daily flow regimes

    Science.gov (United States)

    Bejarano, María Dolores; Sordo-Ward, Álvaro; Alonso, Carlos; Nilsson, Christer

    2017-07-01

    A characterization of short-term changes in river flow is essential for understanding the ecological effects of hydropower plants, which operate by turning the turbines on or off to generate electricity following variations in the market demand (i.e., hydropeaking). The goal of our study was to develop an approach for characterizing the effects of hydropower plant operations on within-day flow regimes across multiple dams and rivers. For this aim we first defined ecologically meaningful metrics that provide a full representation of the flow regime at short time scales from free-flowing rivers and rivers exposed to hydropeaking. We then defined metrics that enable quantification of the deviation of the altered short-term flow regime variables from those of the unaltered state. The approach was successfully tested in two rivers in northern Sweden, one free-flowing and another regulated by cascades of hydropower plants, which were additionally classified based on their impact on short-term flows in sites of similar management. The largest differences between study sites corresponded to metrics describing sub-daily flow magnitudes such as amplitude (i.e., difference between the highest and the lowest hourly flows) and rates (i.e., rise and fall rates of hourly flows). They were closely followed by frequency-related metrics accounting for the numbers of within-day hourly flow patterns (i.e., rises, falls and periods of stability of hourly flows). In comparison, between-site differences for the duration-related metrics were smallest. In general, hydropeaking resulted in higher within-day flow amplitudes and rates and more but shorter periods of a similar hourly flow patterns per day. The impacted flow feature and the characteristics of the impact (i.e., intensity and whether the impact increases or decreases whatever is being described by the metric) varied with season. Our approach is useful for catchment management planning, defining environmental flow targets

  9. An Extended ADOP for Performance Evaluation of Single-Frequency Single-Epoch Positioning by BDS/GPS in Asia-Pacific Region

    Science.gov (United States)

    Liu, Xin; Zhang, Shubi; Zhang, Qiuzhao; Yang, Wei

    2017-01-01

    Single-Frequency Single-Epoch (SFSE) high-precision positioning has always been the hot spot of Global Navigation Satellite System (GNSS), and ambiguity dilution of precision (ADOP) is a well-known scalar measure for success rate of ambiguity resolution. Traditional ADOP expression is complicated, thus the SFSE extended ADOP (E-ADOP), with the newly defined Summation-Multiplication Ratio of Weight (SMRW) and two theorems for short baseline, was developed. This simplifies the ADOP expression; gives a clearer insight into the influences of SMRW and number of satellites on E-ADOP; and makes theoretical analysis of E-ADOP more convenient than that of ADOP, and through that the E-ADOP value can be predicted more accurately than through the ADOP expression for ADOP value. E-ADOP reveals that number of satellites and SMRW or high-elevation satellite are important for ADOP and, through E-ADOP, we studied which factor is dominant to control ADOP in different conditions and make ADOP different between BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), and BDS/GPS. Based on experimental results of SFSE positioning with different baselines, some conclusions are made: (1) ADOP decreases when new satellites are added mainly because the number of satellites becomes larger; (2) when the number of satellites is constant, ADOP is mainly affected by SMRW; (3) in contrast to systems where the satellites with low-elevation are the majority or where low- and high-elevation satellites are equally distributed, in systems where the high-elevation satellites are the majority, the SMRW mainly makes ADOP smaller, even if there are fewer satellites than in the two previous cases, and the difference in numbers of satellites can be expanded as the proportion of high-elevation satellites becomes larger; and (4) ADOP of BDS is smaller than ADOP of GPS mainly because of its SMRW. PMID:28973977

  10. An Extended ADOP for Performance Evaluation of Single-Frequency Single-Epoch Positioning by BDS/GPS in Asia-Pacific Region

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2017-09-01

    Full Text Available Single-Frequency Single-Epoch (SFSE high-precision positioning has always been the hot spot of Global Navigation Satellite System (GNSS, and ambiguity dilution of precision (ADOP is a well-known scalar measure for success rate of ambiguity resolution. Traditional ADOP expression is complicated, thus the SFSE extended ADOP (E-ADOP, with the newly defined Summation-Multiplication Ratio of Weight (SMRW and two theorems for short baseline, was developed. This simplifies the ADOP expression; gives a clearer insight into the influences of SMRW and number of satellites on E-ADOP; and makes theoretical analysis of E-ADOP more convenient than that of ADOP, and through that the E-ADOP value can be predicted more accurately than through the ADOP expression for ADOP value. E-ADOP reveals that number of satellites and SMRW or high-elevation satellite are important for ADOP and, through E-ADOP, we studied which factor is dominant to control ADOP in different conditions and make ADOP different between BeiDou Navigation Satellite System (BDS, Global Positioning System (GPS, and BDS/GPS. Based on experimental results of SFSE positioning with different baselines, some conclusions are made: (1 ADOP decreases when new satellites are added mainly because the number of satellites becomes larger; (2 when the number of satellites is constant, ADOP is mainly affected by SMRW; (3 in contrast to systems where the satellites with low-elevation are the majority or where low- and high-elevation satellites are equally distributed, in systems where the high-elevation satellites are the majority, the SMRW mainly makes ADOP smaller, even if there are fewer satellites than in the two previous cases, and the difference in numbers of satellites can be expanded as the proportion of high-elevation satellites becomes larger; and (4 ADOP of BDS is smaller than ADOP of GPS mainly because of its SMRW.

  11. Impact of the Geoplasma on a Spaceborne GPS(Global Positioning System) Receiver System - A Preliminary Study

    Science.gov (United States)

    1989-02-28

    It is well-known that the TEC is the prime indicator of group path delay for earth-space paths and Klobuchar of AFGL has developed a number of region...specific models. The "community" of those who make it a business to study TEC and led by Klobuchar , has also exploited the so-called BENT model to...Algorithm developed by Klobuchar [1975]. It is designed to correct for approximately 50 Z of the delay error for GPS users ... this error being largely

  12. GPS positioning and desktop mapping. Applications to environmental monitoring. Report on task JNT B898 on the Finnish support programme to IAEA safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Kansanaho, A.; Ilander, T.; Toivonen, H.

    1995-10-01

    Satellite navigation has been used for in-field applications by the Finnish Centre for Radiation and Nuclear Safety since 1993. Because of this experience, training in the use of GPS positioning and desktop mapping was chosen as a task under the Finnish Support programme to IAEA safeguards. A lecture and a field experiment was held in the training course on environmental monitoring at the IAEA headquarters in June 1995. Real-time mapping of the co-ordinates and storing information on sampling sites and procedures can make safeguards implementation more efficient and effective. Further software development are needed for these purposes. (author) (6 figs.).

  13. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  15. A graphical approach to characterize sub-daily flow regimes and evaluate its alterations due to hydropeaking.

    Science.gov (United States)

    Alonso, Carlos; Román, Alfonso; Bejarano, Maria Dolores; Garcia de Jalon, Diego; Carolli, Mauro

    2017-01-01

    Most flow regime characterizations focus on long time scale flow patterns, which are not precise enough to capture key components of short-term flow fluctuations. Recent proposed methods describing sub-daily flow fluctuations are focused on limited components of the flow regime being unable to fully represent it, or on the identification of peaking events based on subjectively defined thresholds, being unsuitable for evaluations of short-term flow regime alterations through comparisons between regulated and free-flowing rivers. This study aims to launch an innovative approach based on the visual display of quantitative information to address the challenge of the short-term hydrologic characterization and evaluation of alteration resulting from hydropeaking. We propose a graphical method to represent a discrete set of ecologically relevant indices that characterize and evaluate the alteration of sub-daily flow regimes. The frequency of occurrence of classified values of a descriptive hydrological variable is represented in a map-like graph where longitude, latitude and altitude represent the Julian day, the value of the variable and the frequency of occurrence, respectively. Subsequently, we tested the method on several rivers, both free-flowing and subjected to hydropower production. The advantages of our approach compared to other analytical methods are: (i) it displays a great amount of information without oversimplification; (ii) it takes into account changes in the intensity, timing and frequency of the sub-daily flows, without needing a priori defined thresholds to identify hydropeaking events; and (iii) it supports the Water Framework Directive goal. Specifically, results from applications of our graphical method agree with Sauterleute and Charmasson (2014) analytical method. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. GPS Composite Clock Analysis

    OpenAIRE

    Wright, James R.

    2008-01-01

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

  17. Characteristics of atmospheric gravity waves observed using the MU (Middle and Upper atmosphere) radar and GPS (Global Positioning System) radio occultation

    Science.gov (United States)

    TSUDA, Toshitaka

    2014-01-01

    The wind velocity and temperature profiles observed in the middle atmosphere (altitude: 10–100 km) show perturbations resulting from superposition of various atmospheric waves, including atmospheric gravity waves. Atmospheric gravity waves are known to play an important role in determining the general circulation in the middle atmosphere by dynamical stresses caused by gravity wave breaking. In this paper, we summarize the characteristics of atmospheric gravity waves observed using the middle and upper atmosphere (MU) radar in Japan, as well as novel satellite data obtained from global positioning system radio occultation (GPS RO) measurements. In particular, we focus on the behavior of gravity waves in the mesosphere (50–90 km), where considerable gravity wave attenuation occurs. We also report on the global distribution of gravity wave activity in the stratosphere (10–50 km), highlighting various excitation mechanisms such as orographic effects, convection in the tropics, meteorological disturbances, the subtropical jet and the polar night jet. PMID:24492645

  18. Training GPs in parent consultation skills: an evaluation of training for the Triple P-Positive Parenting Program

    National Research Council Canada - National Science Library

    Sanders, MR; Turner, KM; Maher, C; Tully, LA; McAuliffe, C

    2003-01-01

    BACKGROUND: The Triple P-Positive Parenting Program is a behavioural family intervention program that aims to prevent severe behavioral, emotional and developmental problems in children by enhancing...

  19. An Enhanced UWB-Based Range/GPS Cooperative Positioning Approach Using Adaptive Variational Bayesian Cubature Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Feng Shen

    2015-01-01

    Full Text Available Precise position awareness is a fundamental requirement for advanced applications of emerging intelligent transportation systems, such as collision warning and speed advisory system. However, the achievable level of positioning accuracy using global navigation satellite systems does not meet the requirements of these applications. Fortunately, cooperative positioning (CP techniques can improve the performance of positioning in a vehicular ad hoc network (VANET through sharing the positions between vehicles. In this paper, a novel enhanced CP technique is presented by combining additional range-ultra-wide bandwidth- (UWB- based measurements. Furthermore, an adaptive variational Bayesian cubature Kalman filtering (AVBCKF algorithm is proposed and used in the enhanced CP method, which can add robustness to the time-variant measurement noise. Based on analytical and experimental results, the proposed AVBCKF-based CP method outperforms the cubature Kalman filtering- (CKF- based CP method and extended Kalman filtering- (EKF- based CP method.

  20. GPS Metric Tracking Unit

    Science.gov (United States)

    2008-01-01

    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.

  1. LADOTD GPS technology management plan.

    Science.gov (United States)

    2012-02-01

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

  2. Integrating different tracking systems in football: multiple camera semi-automatic system, local position measurement and GPS technologies.

    Science.gov (United States)

    Buchheit, Martin; Allen, Adam; Poon, Tsz Kit; Modonutti, Mattia; Gregson, Warren; Di Salvo, Valter

    2014-12-01

    Abstract During the past decade substantial development of computer-aided tracking technology has occurred. Therefore, we aimed to provide calibration equations to allow the interchangeability of different tracking technologies used in soccer. Eighty-two highly trained soccer players (U14-U17) were monitored during training and one match. Player activity was collected simultaneously with a semi-automatic multiple-camera (Prozone), local position measurement (LPM) technology (Inmotio) and two global positioning systems (GPSports and VX). Data were analysed with respect to three different field dimensions (small, 14.4 km · h-1) was slightly-to-moderately greater when tracked with Prozone, and accelerations, small-to-very largely greater with LPM. For most of the equations, the typical error of the estimate was of a moderate magnitude. Interchangeability of the different tracking systems is possible with the provided equations, but care is required given their moderate typical error of the estimate.

  3. GPS & Roadpricing

    DEFF Research Database (Denmark)

    Zabic, Martina

    2005-01-01

    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...

  4. 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.

  5. Monitoring recent crustal movements in the Kenya rift valley by global positioning system (GPS) — a proposal

    Science.gov (United States)

    Rostom, R. S.

    There is evidence that the Kenya Rift is active. 1990 witnessed the execution of the Kenya Rift International Seismic Project to study the deep structure of the Kenya Rift. Yet there is no actual measurement of the rate of its spreading. Estimation based on volumes of volcanic rocks extruded over a given period has led to a wide range of estimates (0.2-2 mm/a). There is a need to establish geometrically the real spreading rate at present. The new technology (Global Positioning System) in its precise mode gives a promise to solve the problem. A preliminary network is proposed to consist of 4 points on each of the Rift walls. The logistics of site location, configuration of the network, observation method, frequency, etc. are discussed. The project requires international cooperation for execution.

  6. GPS in Travel and Activity Surveys

    DEFF Research Database (Denmark)

    Nielsen, Thomas Alexander Sick; Hovgesen, Henrik Harder

    2004-01-01

    The use of GPS-positioning as a monitoring tool in travel and activity surveys opens up a range of possibilities. Using a personal GPS device, the locations and movements of respondents can be followed over a longer period of time. It will then be possible to analyse how the use of urban spaces...... 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...

  7. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP) for a Single Frequency Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) Receiver.

    Science.gov (United States)

    Qian, Chuang; Liu, Hui; Zhang, Ming; Shu, Bao; Xu, Longwei; Zhang, Rufei

    2016-12-05

    As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) is proposed. The method uses a Time-differenced Carrier Phase (TDCP) model, which eliminates the Inner-System Bias (ISB) between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM) to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  8. Mapping Tomorrow's Resources: A symposium on the uses of remote sensing, Geographic Information Systems (GIS), and Global Positioning Systems (GPS) for natural resources management

    Energy Technology Data Exchange (ETDEWEB)

    Falconer, A.

    1993-01-01

    The College of Natural Resources recognizes the important role it has in educating natural resources managers and leaders who can provide the guidance and knowledge needed to increase the production of the earth's renewable resources while sustaining and enhancing the global environment and the natural resource base. The College's teaching, research, extension, and service efforts focus on the many aspects of sustained multiple-natural-resources management and their relationship to man. Through its many programs, the College of Natural Resources focuses on solving local, state, national, and global problems to enhance a more efficient and contemporary use of the world's natural resources. Natural Resources and Environmental Issues (NREI) which began publication in 1993, is a technical series that addresses current topics relevant to natural resources and to the environment. The journal is published as a series of volumes, with at least one being issued each year as the proceedings of the Natural Resources Week Symposium. In the issue on Mapping Tommorrow's Resources, the following topics are discussed: Natural Resource Information from Monopoly to Competition; Global Resources and Mission to Planet Earth; Geographic Information Systems (GIS) Systems and Data Management for Global Data Sets in Natural Resources; the Global Resource Information Database; Overview of GIS Technology in Utah State Government; Politically Correct Global Mapping and Monitoring; Integrating Satellite Imagery and GIS into Natural Resources Management; Forest Service Applications of Remote Sensing and the National Training Program; the Position of the Global Positioning System (GPS) in Wildlife and Habitat Mapping; and the Bureau of Land Management's (BLM's) Remote Sensing Program in Utah.

  9. The need for GPS standardization

    Science.gov (United States)

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

    1992-01-01

    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.

  10. Changes in sub-daily precipitation extremes in a global climate model with super-parameterization under CO2 warming

    Science.gov (United States)

    Khairoutdinov, Marat; Zhou, Xin

    2015-04-01

    Virtually all of the projections for future change of extreme precipitation statistics under CO2 warming have been made using global climate models (GCMs) in which clouds and, in particular, convective cloud systems are not explicitly resolved, but rather parameterized. In our study, a different kind of a GCM, a super-parameterized Community Atmosphere Model (SP-CAM), is employed. In SP-CAM, all the conventional cloud parameterizations are replaced with a small-domain cloud resolving model (CRM), called super-parameterization (SP). The SP is embedded in each grid column of the host GCM. The resolution of each embedded CRM is 4 km, which is generally sufficient to explicitly represent deep convection, which is mostly responsible for extreme precipitation events. In this study, we use the SP-CAM to contrast to the present and to conventional climate model, CAM, the sub-daily extreme precipitation statistics in response to the sea-surface temperatures (SSTs) and CO2 levels as projected for the end of 21st century in response to the IPCC AR5 RCP8.5 emission scenario. Different mechanisms for extreme precipitation changes are discussed.

  11. Applications of GPS technologies to field sports.

    Science.gov (United States)

    Aughey, Robert J

    2011-09-01

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

  12. A Comparison of GPS Workload Demands in Match Play and Small-Sided Games by the Positional Role in Youth Soccer

    Directory of Open Access Journals (Sweden)

    Beenham Mathew

    2017-06-01

    Full Text Available The external demands of small-sided games (SSGs according to the positional role are currently unknown. Using a Catapult Minimax X3 5 Hz GPS, with a 100 Hz tri-axial accelerometer, we compared the accumulated tri-axial player workload per min (PLacc·min-1 during friendly youth match play (MP (11 vs. 11 and SSGs (2 vs. 2, 3 vs. 3, and 4 vs. 4. Significant differences existed between all SSGs and MP for PLacc·min-1 (F = 21.91, p < 0.001, η2 = 0.38, and individual X (F = 27.40, p < 0.001, η2 = 0.43, Y (F = 14.50, p < 0.001, η2 = 0.29 and Z (F = 19.28, p < 0.001, η2 = 0.35 axis loads. Across all conditions, mean PLacc·min-1 was greater for midfielders (p = 0.004, CI: 0.68, 4.56 and forwards (p = 0.037, CI: 0.08, 3.97 than central defenders. In all conditions, greater Y axis values existed for wide defenders (p = 0.024, CI: 0.67, 1.38, midfielders (p = 0.006, CI: 0.18, 1.50 and forwards (p = 0.007, CI: 0.17, 0.15 compared to central defenders. Midfielders reported greater Z axis values compared to central defenders (p = 0.002, CI: 0.40, 2.23. We concluded that SSGs elicited greater external loads than MP, and previous studies may have underestimated the demands of SSGs.

  13. A Comparison of GPS Workload Demands in Match Play and Small-Sided Games by the Positional Role in Youth Soccer.

    Science.gov (United States)

    Beenham, Mathew; Barron, David J; Fry, John; Hurst, Howard H; Figueirdo, Antonio; Atkins, Steve

    2017-06-01

    The external demands of small-sided games (SSGs) according to the positional role are currently unknown. Using a Catapult Minimax X3 5 Hz GPS, with a 100 Hz tri-axial accelerometer, we compared the accumulated tri-axial player workload per min (PLacc·min(-1)) during friendly youth match play (MP) (11 vs. 11) and SSGs (2 vs. 2, 3 vs. 3, and 4 vs. 4). Significant differences existed between all SSGs and MP for PLacc·min(-1) (F = 21.91, p < 0.001, η2 = 0.38), and individual X (F = 27.40, p < 0.001, η2 = 0.43), Y (F = 14.50, p < 0.001, η2 = 0.29) and Z (F = 19.28, p < 0.001, η2 = 0.35) axis loads. Across all conditions, mean PLacc·min(-1) was greater for midfielders (p = 0.004, CI: 0.68, 4.56) and forwards (p = 0.037, CI: 0.08, 3.97) than central defenders. In all conditions, greater Y axis values existed for wide defenders (p = 0.024, CI: 0.67, 1.38), midfielders (p = 0.006, CI: 0.18, 1.50) and forwards (p = 0.007, CI: 0.17, 0.15) compared to central defenders. Midfielders reported greater Z axis values compared to central defenders (p = 0.002, CI: 0.40, 2.23). We concluded that SSGs elicited greater external loads than MP, and previous studies may have underestimated the demands of SSGs.

  14. Assessing the importance of spatio-temporal RCM resolution when estimating sub-daily extreme precipitation under current and future climate conditions

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Luchner, J.; Onof, C.

    2017-01-01

    The increase in extreme precipitation is likely to be one of the most significant impacts of climate change in cities due to increased pluvial flood risk. Hence, reliable information on changes in sub-daily extreme precipitation is needed for robust adaptation strategies. This study explores extr...

  15. Scintillation-Hardened GPS Receiver

    Science.gov (United States)

    Stephens, Donald R.

    2015-01-01

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

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

    Science.gov (United States)

    Williamson, Walton R. (Inventor)

    2013-01-01

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

  17. The analogue method for precipitation prediction: finding better analogue situations at a sub-daily time step

    Science.gov (United States)

    Horton, Pascal; Obled, Charles; Jaboyedoff, Michel

    2017-07-01

    Analogue methods (AMs) predict local weather variables (predictands) such as precipitation by means of a statistical relationship with predictors at a synoptic scale. The analogy is generally assessed on gradients of geopotential heights first to sample days with a similar atmospheric circulation. Other predictors such as moisture variables can also be added in a successive level of analogy. The search for candidate situations similar to a given target day is usually undertaken by comparing the state of the atmosphere at fixed hours of the day for both the target day and the candidate analogues. This is a consequence of using standard daily precipitation time series, which are available over longer periods than sub-daily data. However, it is unlikely for the best analogy to occur at the exact same hour for the target and candidate situations. A better analogue situation may be found with a time shift of several hours since a better fit can occur at different times of the day. In order to assess the potential for finding better analogues at a different hour, a moving time window (MTW) has been introduced. The MTW resulted in a better analogy in terms of the atmospheric circulation and showed improved values of the analogy criterion on the entire distribution of the extracted analogue dates. The improvement was found to increase with the analogue rank due to an accumulation of better analogues in the selection. A seasonal effect has also been identified, with larger improvements shown in winter than in summer. This may be attributed to stronger diurnal cycles in summer that favour predictors taken at the same hour for the target and analogue days. The impact of the MTW on the precipitation prediction skill has been assessed by means of a sub-daily precipitation series transformed into moving 24 h totals at 12, 6, and 3 h time steps. The prediction skill was improved by the MTW, as was the reliability of the prediction. Moreover, the improvements were greater for days

  18. Development of stream-subsurface flow module in sub-daily simulation of Escherichia coli using SWAT

    Science.gov (United States)

    Kim, Minjeong; Boithias, Laurie; Cho, Kyung Hwa; Silvera, Norbert; Thammahacksa, Chanthamousone; Latsachack, Keooudone; Rochelle-Newall, Emma; Sengtaheuanghoung, Oloth; Pierret, Alain; Pachepsky, Yakov A.; Ribolzi, Olivier

    2017-04-01

    Water contaminated with pathogenic bacteria poses a large threat to public health, especially in the rural areas in the tropics where sanitation and drinking water facilities are often lacking. Several studies have used the Soil and Water Assessment Tool (SWAT) to predict the export of in-stream bacteria at a watershed-scale. However, SWAT is limited to in-stream processes, such as die-off, resuspension and, deposition; and it is usually implemented on a daily time step using the SCS Curve Number method, making it difficult to explore the dynamic fate and transport of bacteria during short but intense events such as flash floods in tropical humid montane headwaters. To address these issues, this study implemented SWAT on an hourly time step using the Green-Ampt infiltration method, and tested the effects of subsurface flow (LATQ+GWQ in SWAT) on bacterial dynamics. We applied the modified SWAT model to the 60-ha Houay Pano catchment in Northern Laos, using sub-daily rainfall and discharge measurements, electric conductivity-derived fractions of overland and subsurface flows, suspended sediments concentrations, and the number of fecal indicator organism Escherichia coli monitored at the catchment outlet from 2011 to 2013. We also took into account land use change by delineating the watershed with the 3-year composite land use map. The results show that low subsurface flow of less than 1 mm recovered the underestimation of E. coli numbers during the dry season, while high subsurface flow caused an overestimation during the wet season. We also found that it is more reasonable to apply the stream-subsurface flow interaction to simulate low in-stream bacteria counts. Using fecal bacteria to identify and understand the possible interactions between overland and subsurface flows may well also provide some insight into the fate of other bacteria, such as those involved in biogeochemical fluxes both in-stream and in the adjacent soils and hyporheic zones.

  19. Low-cost implementation of Differential GPS using Arduino

    OpenAIRE

    Svaton, Martin

    2016-01-01

    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.

  20. A GPS coverage model

    Science.gov (United States)

    Skidmore, Trent A.

    1994-01-01

    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.

  1. Effect of GPS errors on Emission model

    DEFF Research Database (Denmark)

    Lehmann, Anders; Gross, Allan

    n this paper we will show how Global Positioning Services (GPS) data obtained from smartphones can be used to model air quality in urban settings. The paper examines the uncertainty of smartphone location utilising GPS, and ties this location uncertainty to air quality models. The results presented...

  2. GPS Satellite Simulation Facility

    Data.gov (United States)

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

  3. GPS Separator HD

    CERN Multimedia

    2016-01-01

    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.

  4. Global Positioning System for the Geosciences: Summary and Proceedings of a Workshop on Improving the GPS Reference Station Infrastructure for Earth, Oceanic, and Atmospheric Science Applications

    Science.gov (United States)

    1997-01-01

    This report, which represents the results of the workshop, is divided into two sections. Section I includes an executive summary, a chapter introducing the reader to GPS and its usefulness for Earth, oceanic, and atmospheric research, and four chapters summarizing the themes of the workshop presentations, poster papers, and working group discussions. Section II contains the proceedings of the workshop and is divided into five chapters corresponding to the five categories of invited papers written by workshop speakers and authors of poster papers. The appendices contain additional information about the workshop and the Steering Committee.

  5. Why GPS makes distances bigger than they are

    NARCIS (Netherlands)

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

    2016-01-01

    Global navigation satellite systems such as the Global Positioning System (GPS) is one of the most important sensors for movement analysis. GPS is widely used to record the trajectories of vehicles, animals and human beings. However, all GPS movement data are affected by both measurement and

  6. 78 FR 67132 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2013-11-08

    ... 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...

  7. 77 FR 70421 - GPS Satellite Simulator Control Working Group Meeting

    Science.gov (United States)

    2012-11-26

    ... 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. Positive and negative GPS-TEC ionospheric storm effects during the extreme space weather event of March 2015 over the Brazilian Sector

    Science.gov (United States)

    Fagundes, Paulo Roberto; Fejer, B. G.; Kavutarapu, Venkatesh; Gil Pillat, Valdir; Cardoso, Felipe Antonio; Ribeiro, Brunno Augusto

    2016-07-01

    We studied the response of the ionosphere (F-region) in the Brazilian sector during extreme space weather event of 17 March 2015 using a large network of 102 GPS-TEC stations. It is observed that the Vertical Total Electron Content (VTEC) was severely disturbed during the storm main and recovery phases. A wavelike oscillation with three peaks was observed in the TEC diurnal variation from equator to low latitudes during the storm main phase on 17th and 18th March, 2015. The latitudinal extent of the wavelike oscillation peaks decreased from the beginning of main phase towards the recovery phase. The first peak extended from beyond 0S to 30S, the second occurred from 6S to 25S, whereas the third diurnal peaks was confined from 13S to 25S. In addition, a strong negative phase in VTEC variations was observed during the recovery phase on March 18-19, 2015. This ionospheric negative phase was stronger at low-latitudes than in the equatorial region. Also, two latitudinal chains of GPS-TEC stations from equatorial region to low latitudes in the East and West Brazilian sectors are used to investigate the storm time behavior of the Equatorial Ionization Anomaly (EIA) in the East and West Brazilian sectors. We observed an anomalous behavior in EIA caused by the wavelike oscillations during the storm main phase on 17 March, and suppression of the EIA, resulting from the negative phase in VTEC, in the storm recovery phase.

  9. Brief report: Using global positioning system (GPS) enabled cell phones to examine adolescent travel patterns and time in proximity to alcohol outlets.

    Science.gov (United States)

    Byrnes, Hilary F; Miller, Brenda A; Morrison, Christopher N; Wiebe, Douglas J; Remer, Lillian G; Wiehe, Sarah E

    2016-07-01

    As adolescents gain freedom to explore new environments unsupervised, more time in proximity to alcohol outlets may increase risks for alcohol and marijuana use. This pilot study: 1) Describes variations in adolescents' proximity to outlets by time of day and day of the week, 2) Examines variations in outlet proximity by drinking and marijuana use status, and 3) Tests feasibility of obtaining real-time data to study adolescent proximity to outlets. U.S. adolescents (N = 18) aged 16-17 (50% female) carried GPS-enabled smartphones for one week with their locations tracked. The geographic areas where adolescents spend time, activity spaces, were created by connecting GPS points sequentially and adding spatial buffers around routes. Proximity to outlets was greater during after school and evening hours. Drinkers and marijuana users were in proximity to outlets 1½ to 2 times more than non-users. Findings provide information about where adolescents spend time and times of greatest risk, informing prevention efforts. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  10. LADOTD GPS technology management plan : tech summary.

    Science.gov (United States)

    2012-02-01

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

  11. SMEX03 Airborne GPS Bistatic Radar Data

    Data.gov (United States)

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

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

    African Journals Online (AJOL)

    eobe

    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 ...

  13. VLBI Type Experimental Observation of GPS

    Science.gov (United States)

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

    2010-06-01

    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.

  14. 77 FR 23668 - GPS Satellite Simulator Working Group Notice of Meeting

    Science.gov (United States)

    2012-04-20

    ... 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...

  15. NASA's GPS tracking system for Aristoteles

    Science.gov (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.

    1991-12-01

    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.

  16. Nutrigenomic targeting of carbohydrate craving behavior: can we manage obesity and aberrant craving behaviors with neurochemical pathway manipulation by Immunological Compatible Substances (nutrients) using a Genetic Positioning System (GPS) Map?

    Science.gov (United States)

    Downs, B William; Chen, Amanda L C; Chen, Thomas J H; Waite, Roger L; Braverman, Eric R; Kerner, Mallory; Braverman, Dasha; Rhoades, Patrick; Prihoda, Thomas J; Palomo, Tomas; Oscar-Berman, Marlene; Reinking, Jeffrey; Blum, Seth H; DiNubile, Nicholas A; Liu, H H; Blum, Kenneth

    2009-09-01

    Genetic mediated physiological processes that rely on both pharmacological and nutritional principles hold great promise for the successful therapeutic targeting of reduced carbohydrate craving, body-friendly fat loss, healthy body recomposition, and overall wellness. By integrating an assembly of scientific knowledge on inheritable characteristics and environmental mediators of gene expression, we review the relationship of genes, hormones, neurotransmitters, and nutrients as they correct unwanted weight gain coupled with unhappiness. In contrast to a simple one-locus, one-mechanism focus on pharmaceuticals alone, we hypothesize that the use of nutrigenomic treatment targeting multi-physiological neurological, immunological, and metabolic pathways will enable clinicians to intercede in the process of lipogenesis by promoting lipolysis while attenuating aberrant glucose cravings. In turn, this approach will enhance wellness in a safe and predictable manner through the use of a Genetic Positioning System (GPS) Map. The GPS Map, while presently incomplete, ultimately will serve not only as a blueprint for personalized medicine in the treatment of obesity, but also for the development of strategies for reducing many harmful addictive behaviors and promoting optimal health by using substances compatible with the body's immune system.

  17. Nutrigenomic targeting of carbohydrate craving behavior: Can we manage obesity and aberrant craving behaviors with neurochemical pathway manipulation by Immunological Compatible Substances (nutrients) using a Genetic Positioning System (GPS) Map?

    Science.gov (United States)

    Downs, B. William; Chen, Amanda L.C.; Chen, Thomas J.H.; Waite, Roger L.; Braverman, Eric R.; Kerner, Mallory; Braverman, Dasha; Rhoades, Patrick; Prihoda, Thomas J.; Palomo, Tomas; Oscar-Berman, Marlene; Reinking, Jeffrey; Blum, Seth H.; DiNubile, Nicholas A.; Liu, H.H.; Blum, Kenneth

    2013-01-01

    SUMMARY Genetic mediated physiological processes that rely on both pharmacological and nutritional principles hold great promise for the successful therapeutic targeting of reduced carbohydrate craving, body-friendly fat loss, healthy body recomposition, and overall wellness. By integrating an assembly of scientific knowledge on inheritable characteristics and environmental mediators of gene expression, we review the relationship of genes, hormones, neurotransmitters, and nutrients as they correct unwanted weight gain coupled with unhappiness. In contrast to a simple one-locus, one-mechanism focus on pharmaceuticals alone, we hypothesize that the use of nutrigenomic treatment targeting multi-physiological neurological, immunological, and metabolic pathways will enable clinicians to intercede in the process of lipogenesis by promoting lipolysis while attenuating aberrant glucose cravings. In turn, this approach will enhance wellness in a safe and predictable manner through the use of a Genetic Positioning System (GPS) Map. The GPS Map, while presently incomplete, ultimately will serve not only as a blueprint for personalized medicine in the treatment of obesity, but also for the development of strategies for reducing many harmful addictive behaviors and promoting optimal health by using substances compatible with the body’s immune system. PMID:19450935

  18. Space Station GPS Multipath Analysis and Validation

    Science.gov (United States)

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

    1999-01-01

    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).

  19. Software defined radio for GPS

    OpenAIRE

    Solé Gaset, Marc

    2009-01-01

    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...

  20. GPS Multipath in Urban Environments

    Science.gov (United States)

    Bilich, A.; Sella, G.

    2008-12-01

    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.

  1. Holes: Ionospheric Scintillation, GPS and Imputation

    Science.gov (United States)

    2007-03-01

    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

  2. Phase Correction for GPS Antenna with Nonunique Phase Center

    Science.gov (United States)

    Fink, Patrick W.; Dobbins, Justin

    2005-01-01

    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.

  3. Briefing highlights space weather risks to GPS

    Science.gov (United States)

    Tretkoff, Ernie

    2011-07-01

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

  4. The performance analysis of a real-time integrated INS/GPS vehicle navigation system with abnormal GPS measurement elimination.

    Science.gov (United States)

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

    2013-08-15

    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.

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

    Directory of Open Access Journals (Sweden)

    IM. O. Widyantara

    2015-06-01

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

  6. Evaluation of solar radio bursts' effect on GPS receiver signal tracking within International GPS Service network

    Science.gov (United States)

    Chen, Zhiyu; Gao, Yang; Liu, Zhizhao

    2005-06-01

    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.

  7. Assessing the importance of spatio-temporal RCM resolution when estimating sub-daily extreme precipitation under current and future climate conditions

    DEFF Research Database (Denmark)

    Sunyer Pinya, Maria Antonia; Luchner, J.; Onof, C.

    2017-01-01

    The increase in extreme precipitation is likely to be one of the most significant impacts of climate change in cities due to increased pluvial flood risk. Hence, reliable information on changes in sub-daily extreme precipitation is needed for robust adaptation strategies. This study explores...... extreme precipitation over Denmark generated by the regional climate model (RCM) HIRHAM-ECEARTH at different spatial resolutions (8, 12, 25 and 50km), three RCM from the RiskChange project at 8km resolution and three RCMs from ENSEMBLES at 25km resolution at temporal aggregations from 1 to 48h......) are more consistent across all temporal aggregations in the representation of high-order moments and extreme precipitation. The biases in the spatial pattern of extreme precipitation change across temporal and spatial resolution. The hourly extreme value distributions of the HIRHAM-ECEARTH simulations...

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

    Science.gov (United States)

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

    2005-01-01

    The advancing role of Global Positioning System (GPS) technology in ecology has made studies of animal movement possible for larger and more vagile species. A simple field test revealed that lengths of GPS-based movement data were strongly biased (P<0.001) by effects of forest canopy. Global Positioning System error added an average of 27.5% additional...

  9. Progress on GPS standardization

    Science.gov (United States)

    Thomas, C.

    1993-01-01

    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.

  10. MicroGPS for Low-Cost Orbit Determination

    Science.gov (United States)

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

    1997-07-01

    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.

  11. Physical applications of GPS geodesy: a review.

    Science.gov (United States)

    Bock, Yehuda; Melgar, Diego

    2016-10-01

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

  12. GPS-Aided Video Tracking

    Directory of Open Access Journals (Sweden)

    Udo Feuerhake

    2015-08-01

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

  13. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao

    2009-05-01

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

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

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

    Science.gov (United States)

    Katie M. Moriarty; Clinton W. Epps

    2015-01-01

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

  15. KOORDINIRAN PRENOS GPS PODATKOV MOBILNE NAPRAVE DO STREŽNIKA

    OpenAIRE

    Ravber, Miha

    2012-01-01

    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.

  16. How and Why to Do VLBI on GPS

    Science.gov (United States)

    Dickey, J. M.

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  18. Coordinate Time and Proper Time in the GPS

    Science.gov (United States)

    Matolcsi, T.; Matolcsi, M.

    2008-01-01

    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…

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

    Science.gov (United States)

    March, Kathryn A.

    2012-01-01

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

  20. 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 ...

  1. GPS, su datum vertical.

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

    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.

  2. Bluetooth GPS logger

    OpenAIRE

    Vymětal, Jan

    2009-01-01

    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

  3. Is GPS telemetry location error screening beneficial?

    Science.gov (United States)

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

    2017-01-01

    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.

  4. Discovering Hidden Treasures with GPS Technology

    Science.gov (United States)

    Nagel, Paul; Palmer, Roger

    2014-01-01

    "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…

  5. Integrating GPS with Dead Reckoning Sensors

    DEFF Research Database (Denmark)

    Cederholm, Jens Peter

    2000-01-01

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

  6. Dual RF Astrodynamic GPS Orbital Navigator Satellite

    Science.gov (United States)

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

    2009-01-01

    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.

  7. 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...

  8. Localization system for use in GPS denied environments

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-01

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

  9. Variability in GPS sources

    NARCIS (Netherlands)

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

    2003-01-01

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

  10. Applying GPS to check horizontal control quality

    Directory of Open Access Journals (Sweden)

    Jakub Vincent

    2004-03-01

    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

  11. Update on GPS Modernization Efforts

    Science.gov (United States)

    2015-06-11

    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

  12. ESOLIP - estimate of solid and liquid precipitation at sub-daily time resolution by combining snow height and rain gauge measurements

    Science.gov (United States)

    Mair, E.; Bertoldi, G.; Leitinger, G.; Della Chiesa, S.; Niedrist, G.; Tappeiner, U.

    2013-07-01

    Measuring precipitation in mountain areas is a demanding task, but essential for hydrological and environmental themes. Especially in small Alpine catchments with short hydrological response, precipitation data with high temporal resolution are required for a better understanding of the hydrological cycle. Since most climate/meteorological stations are situated at the easily accessible bottom of valleys, and the few heated rain gauges installed at higher elevation sites are problematic in winter conditions, an accurate quantification of winter (snow) precipitation at high elevations remains difficult. However, there are an increasing number of micro-meteorological stations and snow height sensors at high elevation locations in Alpine catchments. To benefit from data of such stations, an improved approach to estimate solid and liquid precipitation (ESOLIP) is proposed. ESOLIP allows gathering hourly precipitation data throughout the year by using unheated rain gauge data, careful filtering of snow height sensors as well as standard meteorological data (air temperature, relative humidity, global shortwave radiation, wind speed). ESOLIP was validated at a well-equipped test site in Stubai Valley (Tyrol, Austria), comparing results to winter precipitation measured with a snow pillow and a heated rain gauge. The snow height filtering routine and indicators for possible precipitation were tested at a field site in Matsch Valley (South Tyrol, Italy). Results show a good match with measured data because variable snow density is taken into account, which is important when working with freshly fallen snow. Furthermore, the results show the need for accurate filtering of the noise of the snow height signal and they confirm the unreliability of heated rain gauges for estimating winter precipitation. The described improved precipitation estimate ESOLIP at sub-daily time resolution is helpful for precipitation analysis and for several hydrological applications like monitoring

  13. 75 FR 51481 - In the Matter of Certain GPS Devices and Products Containing Same; Modification Proceeding

    Science.gov (United States)

    2010-08-20

    ... 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...

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

    Science.gov (United States)

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

    2000-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Ceva, A.

    2000-07-01

    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)

  16. GPS Precision Timing at CERN

    CERN Document Server

    Beetham, C G

    1999-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jhen-Kai Liao

    2013-08-01

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

  18. Accuracy of High-Rate GPS for Seismology

    Science.gov (United States)

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

    2006-01-01

    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.

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

    National Research Council Canada - National Science Library

    Leejoice, Robert

    2000-01-01

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

  20. Pilot GPS/LORAN Receiver Programming Performance: A Laboratory Evaluation

    Science.gov (United States)

    1994-02-01

    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.

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

    Science.gov (United States)

    2013-12-01

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

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

    National Research Council Canada - National Science Library

    Joseph, Kurt

    1999-01-01

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

  3. ISOLDE target zone GPS robot Camera B Part1

    CERN Multimedia

    2016-01-01

    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.

  4. ISOLDE target zone GPS robot, Camera B Part2

    CERN Multimedia

    2016-01-01

    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.

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

    CERN Multimedia

    2016-01-01

    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.

  6. ISOLDE target zone GPS robot Camera B Part1 HD

    CERN Multimedia

    2016-01-01

    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.

  7. SMEX02 Airborne GPS Bistatic Radar Data, Iowa

    Data.gov (United States)

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

  8. Pretty Easy Pervasive Positioning

    DEFF Research Database (Denmark)

    Hansen, Rene; Wind, Rico; Jensen, Christian Søndergaard

    2009-01-01

    With the increasing availability of positioning based on GPS, Wi-Fi, and cellular technologies and the proliferation of mobile devices with GPS, Wi-Fi and cellular connectivity, ubiquitous positioning is becoming a reality. While offerings by companies such as Google, Skyhook, and Spotigo render...

  9. GPS pseudolites: Theory, design, and applications

    Science.gov (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.

  10. A maritime wireless communication primitive power-supplied by GPS

    Science.gov (United States)

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

    2014-10-01

    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.

  11. An Interdisciplinary Approach at Studying the Earth-Sun System with GPS/GNSS and GPS-like Signals

    Science.gov (United States)

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

    2005-01-01

    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

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

    Science.gov (United States)

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

    2017-01-01

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

  13. Evaluation of some software measuring displacements using GPS in real-time

    Science.gov (United States)

    Langbein, John

    2006-01-01

    (Langbein and Bock, 2004). But, not all locales include strain and tiltmeters. Thus, having the capability to extract signals with periods of less than a day is desirable since the distribution of GPS is more extensive than strain and tilt.At both Parkfield and Long Valley, the USGS has been using other software packages to process the GPS data at sub-daily intervals and in real-time. The underlying goal of these types of measurements is to detect any deformation event as it evolves; the 24 hour processing might not provide timely results if such a deformation event is precursory to a geologic hazard (an earthquake for Parkfield and either a volcanic event or an earthquake for Long Valley).In Long Valley, We use the software package called 3DTracker (http://www.3dtracker.com, http://www.condorearth.com) to estimate the changes of in position of a remote site relative to a “fixed” site. The 3DTracker software uses double difference GPS code measurements and receiversatellite-time triple differences from one epoch to the next of the GPS phase data (a proxy for travel-time measurements) and employs a Kalman filter to obtain stability in the estimate of position. That is, the estimate of the current position depends upon the estimate of the prior position. Hence, a time series of position looks fairly smooth depending upon the coefficient selected for the Kalman filter. With triple differences, the sometimes troublesome initial integer cycle ambiguity terms cancel (number of wavelengths between the receiver and each satellite), but only the incremental change in position is calculated. This triple difference Kalman filter solution is slow to converge and less accurate than a double difference (e.g., RTD, Track) solution, but it is robust and computationally efficient (Remondi and Brown, 2000). 3D-Tracker allows use of various single-frequency and dual-frequency GPS phase and code observables including the ionospheric-free combinations (known as LC or L3 and P(L3)) formed

  14. Regional and Local Geoid Undulations for Computing Orthometric Heights from GPS Measurements Project

    Data.gov (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...

  15. Sensing Human Activity: GPS Tracking.

    Science.gov (United States)

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

    2009-01-01

    THE ENHANCEMENT OF GPS TECHNOLOGY ENABLES THE USE OF GPS DEVICES NOT ONLY AS NAVIGATION AND ORIENTATION TOOLS, BUT ALSO AS INSTRUMENTS USED TO CAPTURE TRAVELLED ROUTES: as sensors that measure activity on a city scale or the regional scale. TU Delft developed a process and database architecture for collecting data on pedestrian movement in three European city centres, Norwich, Rouen and Koblenz, and in another experiment for collecting activity data of 13 families in Almere (The Netherlands) for one week. The question posed in this paper is: what is the value of GPS as 'sensor technology' measuring activities of people? The conclusion is that GPS offers a widely useable instrument to collect invaluable spatial-temporal data on different scales and in different settings adding new layers of knowledge to urban studies, but the use of GPS-technology and deployment of GPS-devices still offers significant challenges for future research.

  16. Sensing Human Activity: GPS Tracking

    Science.gov (United States)

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

    2009-01-01

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

  17. Fundamentals of GPS Receivers A Hardware Approach

    CERN Document Server

    Doberstein, Dan

    2012-01-01

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

  18. Using Transponders on the Moon to Increase Accuracy of GPS

    Science.gov (United States)

    Penanen, Konstantin; Chui, Talso

    2008-01-01

    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.

  19. New approach for earthquake/tsunami monitoring using dense GPS networks.

    Science.gov (United States)

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

    2013-01-01

    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.

  20. Cooperative Localization in GPS-Limited Urban Environments

    Science.gov (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.

  1. Saved by Iridium? An Alternative to GPS

    Science.gov (United States)

    2012-05-17

    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.” http://www.goodreads.com/author/quotes/ 14190

  2. GPS Technology for the Development of Business Information Systems

    OpenAIRE

    Muresan, Mihaela

    2006-01-01

    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...

  3. Continuous professional development for GPs

    DEFF Research Database (Denmark)

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

    2014-01-01

    . 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...

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

    Science.gov (United States)

    Pistoll, Chance; Furler, John

    2017-10-01

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

  5. De GPS al mapa

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Kenji Oguni

    2013-12-01

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

  7. 75 FR 76024 - In the Matter of Certain GPS Devices and Products Containing Same; Enforcement Proceeding; Notice...

    Science.gov (United States)

    2010-12-07

    ... COMMISSION In the Matter of Certain GPS Devices and Products Containing Same; Enforcement Proceeding; Notice... importation of certain global positioning system (``GPS'') devices and products containing the same by reason... and cease-and-desist orders against SiRF, Pharos, and Mio. The remedial orders are directed to GPS...

  8. 75 FR 3901 - Announcement of IS-GPS-200E Interface Control Working Group (ICWG) Teleconference Meeting

    Science.gov (United States)

    2010-01-25

    ... Department of the Air Force Announcement of IS-GPS-200E Interface Control Working Group (ICWG) Teleconference... notice informs the public that the Global Positioning Systems Wing will be hosting an Interface Control Working Group (ICWG) teleconference meeting for the document IS-GPS-200E (NAVSTAR GPS Space Segment...

  9. Ionospheric corrections for GPS time transfer

    Science.gov (United States)

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

    2014-03-01

    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.

  10. 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...

  11. High dynamic GPS receiver validation demonstration

    Science.gov (United States)

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

    1985-01-01

    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.

  12. GPS Estimates of Integrated Precipitable Water Aid Weather Forecasters

    Science.gov (United States)

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

    2013-01-01

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

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

    DEFF Research Database (Denmark)

    Jensen, Kjeld; Larsen, Morten; Simonsen, Tom

    2012-01-01

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

  14. Hastighedskort for Danmark vha. GPS

    DEFF Research Database (Denmark)

    Andersen, Ove; Lahrmann, Harry; Torp, Kristian

    2011-01-01

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

  15. 75 FR 8928 - Announcement of IS-GPS-200, IS-GPS-705, IS-GPS-800 Interface Control Working Group (ICWG...

    Science.gov (United States)

    2010-02-26

    ... Department of 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...

  16. Signal-to-Noise Ratio Prediction and Validation for Space Shuttle GPS Flight Experiment

    Science.gov (United States)

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

    2002-01-01

    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.

  17. Improvement and Refinement of the GPS/MET Data Analysis Algorithm

    Science.gov (United States)

    Herman, Benjamin M.

    2003-01-01

    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.

  18. Soil Moisture Retrieval Based on GPS Signal Strength Attenuation

    Directory of Open Access Journals (Sweden)

    Franziska Koch

    2016-07-01

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

  19. Snow Depth with GPS: Case Study from Minnesota 2010-2011

    Science.gov (United States)

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

    2011-12-01

    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

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

    Directory of Open Access Journals (Sweden)

    Krzysztof Bikonis

    2013-09-01

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

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    N. Jakowski

    1996-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Craig Roberts

    2011-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Qasim Ali

    2014-09-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Yuanjin Pan

    2015-10-01

    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.

  6. Nuclear-Powered GPS Spacecraft Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Bernard

    1977-05-01

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

  7. Study of differential GPS system for UAVs

    OpenAIRE

    Trujillo Martí, Oriol

    2016-01-01

    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...

  8. Estimation of interfrequency receiver biases in Korean Peninsula using GPS measurements

    Science.gov (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.

  9. Using GPS to Detect Imminent Tsunamis

    Science.gov (United States)

    Song, Y. Tony

    2009-01-01

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

  10. Human factors evaluation of TSO-C129A GPS receivers

    Science.gov (United States)

    1998-10-22

    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 ...

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

    Science.gov (United States)

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

    2017-06-17

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

  12. A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

    Science.gov (United States)

    Seo, Jiwon; Chen, Yu-Hsuan; De Lorenzo, David S.; Lo, Sherman; Enge, Per; Akos, Dennis; Lee, Jiyun

    2011-01-01

    Due to their weak received signal power, Global Positioning System (GPS) signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs). However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR) with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU) coupled with a new generation Graphics Processing Unit (GPU) having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities. PMID:22164116

  13. A Real-Time Capable Software-Defined Receiver Using GPU for Adaptive Anti-Jam GPS Sensors

    Directory of Open Access Journals (Sweden)

    Dennis Akos

    2011-09-01

    Full Text Available Due to their weak received signal power, Global Positioning System (GPS signals are vulnerable to radio frequency interference. Adaptive beam and null steering of the gain pattern of a GPS antenna array can significantly increase the resistance of GPS sensors to signal interference and jamming. Since adaptive array processing requires intensive computational power, beamsteering GPS receivers were usually implemented using hardware such as field-programmable gate arrays (FPGAs. However, a software implementation using general-purpose processors is much more desirable because of its flexibility and cost effectiveness. This paper presents a GPS software-defined radio (SDR with adaptive beamsteering capability for anti-jam applications. The GPS SDR design is based on an optimized desktop parallel processing architecture using a quad-core Central Processing Unit (CPU coupled with a new generation Graphics Processing Unit (GPU having massively parallel processors. This GPS SDR demonstrates sufficient computational capability to support a four-element antenna array and future GPS L5 signal processing in real time. After providing the details of our design and optimization schemes for future GPU-based GPS SDR developments, the jamming resistance of our GPS SDR under synthetic wideband jamming is presented. Since the GPS SDR uses commercial-off-the-shelf hardware and processors, it can be easily adopted in civil GPS applications requiring anti-jam capabilities.

  14. 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

  15. Algorithms for Global Positioning

    DEFF Research Database (Denmark)

    Borre, Kai; Strang, Gilbert

    and replaces the authors' previous work, Linear Algebra, Geodesy, and GPS (1997). An initial discussion of the basic concepts, characteristics and technical aspects of different satellite systems is followed by the necessary mathematical content which is presented in a detailed and self-contained fashion....... At the heart of the matter are the positioning algorithms on which GPS technology relies, the discussion of which will affirm the mathematical contents of the previous chapters. Numerous ready-to-use MATLAB codes are included for the reader. This comprehensive guide will be invaluable for engineers...... and academic researchers who wish to master the theory and practical application of GPS technology....

  16. GPs' mental wellbeing and psychological resources: a cross-sectional survey.

    Science.gov (United States)

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

    2017-08-01

    The negative impact of work has been the traditional focus of GP surveys. We know little about GP positive mental health and psychological resources. To profile and contextualise GP positive mental health and personal psychological resources. Cross-sectional survey of GPs working in Northern Ireland (NI). A questionnaire comprising the Warwick Edinburgh Mental Wellbeing Scale (WEMWBS) and measures of resilience, optimism, self-efficacy, and hope, and sociodemographic information was posted to 400 GPs randomly selected from a publicly available GP register. The response rate was 55% (n = 221 out of 400). Mean value for GP wellbeing (WEMWBS) was 50.2 (standard deviation [SD] 8) compared to UK vets 48.8 (SD 9), UK teachers 47.2 (SD 9), and the population of NI 50.8 (SD 9). After adjustment for confounding, mean WEMWBS was 2.4 units (95% CI = 0.02 to 4.7) higher in female GPs than males (P = 0.05), and 4.0 units (95% CI = 0.8 to 7.3) higher in GPs ≥55 years than GPs ≤44 years (P = 0.02). Optimism was 1.1 units higher in female GPs than male GPs (95% CI = 0.1 to 2.0), and 1.56 units higher in GPs ≥55 years (95% CI = 0.2 to 2.9) than in those ≤44 years. Hope was 3 units higher in GPs ≥55 years (95% CI = 0.4 to 5.7) than in those aged 45-54 years. Correlation between WEMWBS and psychological resources was highest with hope (r = 0.65, P 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.

  17. A study of ionospheric grid modification technique for BDS/GPS receiver

    Science.gov (United States)

    Liu, Xuelin; Li, Meina; Zhang, Lei

    2017-07-01

    For the single-frequency GPS receiver, ionospheric delay is an important factor affecting the positioning performance. There are many kinds of ionospheric correction methods, common models are Bent model, IRI model, Klobuchar model, Ne Quick model and so on. The US Global Positioning System (GPS) uses the Klobuchar coefficients transmitted in the satellite signal to correct the ionospheric delay error for a single frequency GPS receiver, but this model can only reduce the ionospheric error of about 50% in the mid-latitudes. In the Beidou system, the accuracy of the correction delay is higher. Therefore, this paper proposes a method that using BD grid information to correct GPS ionospheric delay to improve the ionospheric delay for the BDS/GPS compatible positioning receiver. In this paper, the principle of ionospheric grid algorithm is introduced in detail, and the positioning accuracy of GPS system and BDS/GPS compatible positioning system is compared and analyzed by the real measured data. The results show that the method can effectively improve the positioning accuracy of the receiver in a more concise way.

  18. Estimating waste transfer station delays using GPS.

    Science.gov (United States)

    Wilson, Bruce Gordon; Vincent, Julie K

    2008-01-01

    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.

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

    Science.gov (United States)

    Star, Mikhael; Collette, Lanita

    2010-01-01

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

  20. Troposphere Modeling and Filtering for Precise GPS Leveling

    NARCIS (Netherlands)

    Kleijer, F.

    2004-01-01

    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,

  1. Evaluation of EGM2008 by means of GPS Levelling Uganda

    African Journals Online (AJOL)

    Personal

    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 (http://www-gpsg.mit.edu). To control processing, the software ...

  2. 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 ...

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

    Directory of Open Access Journals (Sweden)

    S. Gandolfi

    2001-06-01

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

  4. CLPX-Airborne: Airborne GPS Bistatic Radar

    Data.gov (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...

  5. GPS Attitude Determination for Launch Vehicles Project

    Data.gov (United States)

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

  6. GPS operations at Olkiluoto in 2011

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-06-15

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

  7. Global Positioning System Bibliography

    Science.gov (United States)

    1992-03-01

    316. Buisson, J. A., 0. J. Oaks, and H. Warren (1985). "Absolute calibration and precise positioning between major European time observatories and...Fla, 29 November-2 December, pp. 39-46. Krakiwsky, E. J., B. Wanless, B. Buffett , K. P. Schwarz, and M. Nakiboglu (1985). "GPS orbit improvement and...K. P. Schwarz, E. J. Krakiwsky, B. Buffett , and B. Wanless (1984). "A multi-pass, multi-station approach to GPS orbital improvement and precise

  8. Simulation and Performance Evaluations of the New GPS L5 and L1 Signals

    Directory of Open Access Journals (Sweden)

    Tahir Saleem

    2017-01-01

    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.

  9. Concurrent Validity of GPS for Deriving Mechanical Properties of Sprint Acceleration.

    Science.gov (United States)

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

    2017-01-01

    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

    2015-07-01

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-24

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

  12. Predicting metabolic rate during level and uphill outdoor walking using a low-cost GPS receiver.

    Science.gov (United States)

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

    2016-08-01

    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.

  13. A New Algorithm for ABS/GPS Integration Based on Fuzzy-Logic in Vehicle Navigation System

    Directory of Open Access Journals (Sweden)

    Ali Amin Zadeh

    2011-10-01

    Full Text Available GPS based vehicle navigation systems have difficulties in tracking vehicles in urban canyons due to poor satellite availability. ABS (Antilock Brake System Navigation System consists of self-contained optical encoders mounted on vehicle wheels that can continuously provide accurate short-term positioning information. In this paper, a new concept regarding GPS/ABS integration, based on Fuzzy Logic is presented. The proposed algorithm is used to identify GPS position accuracy based on environment and vehicle dynamic knowledge. The GPS is used as reference during the time it is in a good condition and replaced by ABS positioning system when GPS information is unreliable. We compare our proposed algorithm with other common algorithm in real environment. Our results show that the proposed algorithm can significantly improve the stability and reliability of ABS/GPS navigation system.

  14. Optimization of GPS Interferometric Reflectometry for Remote Sensing

    Science.gov (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

  15. Contents of GPS Data Files

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-09

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

  16. Mw 8.5 BENGKULU EARTHQUAKES FROM CONTINUOUS GPS DATA

    Directory of Open Access Journals (Sweden)

    W. A. W. Aris

    2016-09-01

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

  17. Enjoying a healthy pregnancy: GPs' essential role in health promotion.

    Science.gov (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.

  18. Reduction Vehicle Speed Using GPS Android Smart Phone Programming

    Directory of Open Access Journals (Sweden)

    Sameer Sami Hassan

    2017-07-01

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

  19. Global GPS Ionospheric Modelling Using Spherical Harmonic Expansion Approach

    Directory of Open Access Journals (Sweden)

    Byung-Kyu Choi

    2010-12-01

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

  20. Diagnosing dementia with confidence by GPs.

    NARCIS (Netherlands)

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

    2007-01-01

    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.

  1. The SMS-GPS-Trip-Method

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  2. Measurement of stride parameters using a wearable GPS and inertial measurement unit.

    Science.gov (United States)

    Tan, Huiling; Wilson, Alan M; Lowe, John

    2008-01-01

    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.

  3. TAGGING, TRACKING AND LOCATING WITHOUT GPS

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-08

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

  4. GPS and Injury Prevention in Professional Soccer.

    Science.gov (United States)

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

    2016-02-01

    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.

  5. At-sea aerial survey GPS points in southern California, 1999-2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This file contains the flight trackline Global Positioning System (GPS) point data from the aerial surveys. Surveys were flown at 60 meters (200 feet) above sea...

  6. An Advanced, Low-Cost, GPS-Based Animal Tracking System

    National Research Council Canada - National Science Library

    Patrick E. Clark; Douglas E. Johnson; Mark A. Kniep; Phillip Jermann; Brad Huttash; Andrew Wood; Michael Johnson; Craig McGillivan; Kevin Titus

    2006-01-01

    Abstract An improved global positioning system (GPS)–based animal tracking system is needed to meet quickly evolving demands of ecological research, range livestock production, and natural resource management...

  7. Miniaturized Radiation Hardened Beam-Steerable GPS Receiver Front End Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Position, Navigation and Timing (PNT) capability via GPS services are used by NASA for (1) real-time on-board autonomous navigation, (2) attitude determination and...

  8. Daily GPS-Derived Estimates Of Axis Of Rotation Of Earth

    Science.gov (United States)

    Lindqwister, Ulf J.; Blewitt, Geoffrey; Freedman, Adam

    1994-01-01

    Report describes study in which data gathered by worldwide network of 21 Global Positioning System (GPS) receivers during 3-week experiment in January and February 1991 used to estimate location of axis of rotation of Earth.

  9. Variable Terrestrial GPS Telemetry Detection Rates: Parts 1 - 7—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Studies utilizing Global Positioning System (GPS) telemetry rarely result in 100% fix success rates (FSR). Many assessments of wildlife resource use do not account...

  10. Using 1-Hz GPS data to measure deformations caused by the Denali fault earthquake.

    Science.gov (United States)

    Larson, Kristine M; Bodin, Paul; Gomberg, Joan

    2003-05-30

    The 3 November 2002 moment magnitude 7.9 Denali fault earthquake generated large, permanent surface displacements in Alaska and large-amplitude surface waves throughout western North America. We find good agreement between strong ground-motion records integrated to displacement and 1-hertz Global Positioning System (GPS) position estimates collected approximately 140 kilometers from the earthquake epicenter. One-hertz GPS receivers also detected seismic surface waves 750 to 3800 kilometers from the epicenter, whereas these waves saturated many of the seismic instruments in the same region. High-frequency GPS increases the dynamic range and frequency bandwidth of ground-motion observations, providing another tool for studying earthquake processes.

  11. 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

    2014-01-01

    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....

  12. A Framework For Using GPS Data In Physical Activity And Sedentary Behavior Studies

    DEFF Research Database (Denmark)

    Jankowska, Marta M; Schipperijn, Jasper; Kerr, Jacqueline

    2015-01-01

    Global Positioning Systems (GPS) are increasingly applied in activity studies, yet significant theoretical and methodological challenges remain. This paper presents a framework for integrating GPS data with other technologies to create dynamic representations of behaviors in context. Utilizing more...... accurate and sensitive measures to link behavior and environmental exposures allows for new research questions and methods to be developed. SUMMARY: Global Positioning Systems can be linked with other technologies to create dynamic representations of behaviors in context....

  13. GPS acquisition solution for use cases in all types of environments

    OpenAIRE

    Al Bitar-El Natour, Hanaa; Escher, Anne-Christine; Macabiau, Christophe; Julien, Olivier; Monnerat, Michel

    2006-01-01

    International audience; The dramatic increase of Location Based Services and other location and navigation applications gives rise to a crucial need to improve positioning solutions. Currently, the American GPS is the only operational satellite based positioning system as the European Galileo system will be operational by 2010. Hence, this paper only deals with GPS receivers. The Time To First Fix (TTFF) and the sensitivity are the key drivers for their performance evaluation. The TTFF is the...

  14. A Forward GPS Multipath Simulator Based on the Vegetation Radiative Transfer Equation Model.

    Science.gov (United States)

    Wu, Xuerui; Jin, Shuanggen; Xia, Junming

    2017-06-05

    Global Navigation Satellite Systems (GNSS) have been widely used in navigation, positioning and timing. Nowadays, the multipath errors may be re-utilized for the remote sensing of geophysical parameters (soil moisture, vegetation and snow depth), i.e., GPS-Multipath Reflectometry (GPS-MR). However, bistatic scattering properties and the relation between GPS observables and geophysical parameters are not clear, e.g., vegetation. In this paper, a new element on bistatic scattering properties of vegetation is incorporated into the traditional GPS-MR model. This new element is the first-order radiative transfer equation model. The new forward GPS multipath simulator is able to explicitly link the vegetation parameters with GPS multipath observables (signal-to-noise-ratio (SNR), code pseudorange and carrier phase observables). The trunk layer and its corresponding scattering mechanisms are ignored since GPS-MR is not suitable for high forest monitoring due to the coherence of direct and reflected signals. Based on this new model, the developed simulator can present how the GPS signals (L1 and L2 carrier frequencies, C/A, P(Y) and L2C modulations) are transmitted (scattered and absorbed) through vegetation medium and received by GPS receivers. Simulation results show that the wheat will decrease the amplitudes of GPS multipath observables (SNR, phase and code), if we increase the vegetation moisture contents or the scatters sizes (stem or leaf). Although the Specular-Ground component dominates the total specular scattering, vegetation covered ground soil moisture has almost no effects on the final multipath signatures. Our simulated results are consistent with previous results for environmental parameter detections by GPS-MR.

  15. Validation of GPS and accelerometer technology in swimming.

    Science.gov (United States)

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

    2014-03-01

    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.

  16. Investigating Atmospheric Rivers using GPS PW from Ocean Transits

    Science.gov (United States)

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

    2014-12-01

    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.

  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

    2010-01-01

    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

    Science.gov (United States)

    Neilan, Ruth E.; Dixon, T. H.; Meehan, Thomas K.; Melbourne, William G.; Scheid, John A.; Kellogg, J. N.; Stowell, J. L.

    1989-01-01

    For three weeks, from January 18 to February 5, 1988, scientists and engineers from 13 countries and 30 international agencies and institutions cooperated in the most extensive GPS (Global Positioning System) field campaign, and the largest geodynamics experiment, in the world to date. This collaborative eperiment concentrated GPS receivers in Central and South America. The predicted rates of motions are on the order of 5-10 cm/yr. Global coverage of GPS observations spanned 220 deg of longitude and 125 deg of latitude using a total of 43 GPS receivers. The experiment was the first civilian effort at implementing an extended international GPS satellite tracking network. Covariance analyses incorporating the extended tracking network predicted significant improvement in precise orbit determination, allowing accurate long-baseline geodesy in the science areas.

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

    Science.gov (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

  20. Review of current GPS methodologies for producing accurate time series and their error sources

    Science.gov (United States)

    He, Xiaoxing; Montillet, Jean-Philippe; Fernandes, Rui; Bos, Machiel; Yu, Kegen; Hua, Xianghong; Jiang, Weiping

    2017-05-01

    The Global Positioning System (GPS) is an important tool to observe and model geodynamic processes such as plate tectonics and post-glacial rebound. In the last three decades, GPS has seen tremendous advances in the precision of the measurements, which allow researchers to study geophysical signals through a careful analysis of daily time series of GPS receiver coordinates. However, the GPS observations contain errors and the time series can be described as the sum of a real signal and noise. The signal itself can again be divided into station displacements due to geophysical causes and to disturbing factors. Examples of the latter are errors in the realization and stability of the reference frame and corrections due to ionospheric and tropospheric delays and GPS satellite orbit errors. There is an increasing demand on detecting millimeter to sub-millimeter level ground displacement signals in order to further understand regional scale geodetic phenomena hence requiring further improvements in the sensitivity of the GPS solutions. This paper provides a review spanning over 25 years of advances in processing strategies, error mitigation methods and noise modeling for the processing and analysis of GPS daily position time series. The processing of the observations is described step-by-step and mainly with three different strategies in order to explain the weaknesses and strengths of the existing methodologies. In particular, we focus on the choice of the stochastic model in the GPS time series, which directly affects the estimation of the functional model including, for example, tectonic rates, seasonal signals and co-seismic offsets. Moreover, the geodetic community continues to develop computational methods to fully automatize all phases from analysis of GPS time series. This idea is greatly motivated by the large number of GPS receivers installed around the world for diverse applications ranging from surveying small deformations of civil engineering structures (e

  1. GPs' experiences of children with anxiety disorders in primary care: a qualitative study.

    Science.gov (United States)

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

    2017-12-01

    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.

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

    Directory of Open Access Journals (Sweden)

    K. Boniface

    2009-07-01

    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.

  3. 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)

    2009-07-01

    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.)

  4. GPS sensing of precipitable water vapour during the March 2010 Melbourne storm

    Science.gov (United States)

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

    2013-11-01

    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.

  5. High dynamic, low volume GPS receiver

    Science.gov (United States)

    Hurd, W. J.

    1983-01-01

    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.

  6. Quantifying deformation in North Borneo with GPS

    Science.gov (United States)

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

    2017-10-01

    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

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

    OpenAIRE

    Blažek, Martin

    2009-01-01

    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...

  8. The Mathematics of the Global Positioning System.

    Science.gov (United States)

    Nord, Gail D.; Jabon, David; Nord, John

    1997-01-01

    Presents an activity that illustrates the application of mathematics to modern navigation and utilizes the Global Positioning System (GPS). GPS is a constellation of 24 satellites that enables receivers to compute their position anywhere on the earth with great accuracy. (DDR)

  9. Implementasi Sistem Pelacakan Kendaraan Bermotor Menggunakan Gps Dan Gprs Dengan Integrasi Googlemap

    Directory of Open Access Journals (Sweden)

    Yazid Dul Muchlisin

    2011-07-01

    Full Text Available Abstract— Vehicle tracking system using GPS and GPRS integration googlemap provide information that is maximized with the technology of GPS (Global Positioning System receiver which can indicate the position of the vehicle with the map and the ability of the appointment of direction and position coordinates (x, y or latitude, longitude textually and visual at any location. Vehicle tracking system is built using equipment GIS (Geographic Information System and dedicated to smartphones which support Global Positioning System (GPS, as well as portable computers, using General Packet Radio Service (GPRS as a connection to the internet. The hardware used is a smartphone that supports GPS with supporting tools used are GoogleMaps, Notepad + +, NetBeans IDE 6.5.1, Mysql, Java (J2ME, PHP, JavaScript. The results of this system in the form of tracking system capable of monitoring the movement of vehicles on an ongoing position by utilizing GPS and GPRS as the sender of the wireless data and Internet connections.   Keywords— GIS, GPS, GPRS, googlemaps, J2ME,

  10. Cooperative Positioning in Wireless Sensor Networks Using Semidefinite Programming

    OpenAIRE

    Monir Vaghefi, Sayed Reza

    2015-01-01

    With the rapid development of wireless technologies, the demand for positioning services has grown dramatically over the past three decades. The Global Positioning System (GPS) is widely used in wireless devices for positioning purposes. However, in addition to having bulky and expensive equipment, GPS receivers do not operate properly in dense and indoor environments. Difficulties in using GPS lead us to use sensor localization in which the position information is obtained from the measureme...

  11. A civil complement to GPS and Glonass

    Science.gov (United States)

    Rosetti, C.

    1989-10-01

    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.

  12. Design and testing of a GPS/GSM collar prototype to combat cattle rustling

    Directory of Open Access Journals (Sweden)

    Francesco M. Tangorra

    2013-10-01

    Full Text Available Rustling is an age-old practice that was widespread in Italy until the first half of the 20th century. Today, incidents of cattle rustling are again being reported. However, the problem is not only found in Italy. It is also becoming a plague for ranchers in the US and is still rampant in East Africa. In Italy, the cattle rustling phenomena have usually been limited through the direct control of the herdsmen. Global positioning system (GPS and geographic information system (GIS combined technologies are increasingly applied for tracking and monitoring livestock with greater spatial and temporal resolution. However, so far, no case studies of the use of GPS technology to combat cattle rustling have been reported in the literature. The aim of this research was to develop a GPS/GSM (global system for mobile communication collar, using commercial hardware and implementing a specific software [ARVAshepherd 1.0; ARVAtec Srl, Rescaldina (MI, Italy] to track animals’ movements outside their grazing area and to signal when animals are straying outside virtual perimeters. A phase I study was conducted from January to June 2011 to build the GPS/GSM collar and to assess its performances in terms of GPS accuracy and precision, while a phase II study was conducted in July 2011 to test the GPS collar under real-life operating conditions. The static GPS positioning error achieved a circular error probable (50% and horizontal 95% accuracy of 1.462 m and 4.501 m, respectively. This is comparable with values obtained by other authors in static tests of a commercial GPS collar for grazing studies. In field tests, the system was able to identify the incorrect position of the cattle and the warning messages were sent promptly to the farmer, continuing until the animals had been repositioned inside the fence, thus highlighting the potential of the GPS/GSM collar as an anti-theft system.

  13. Glacial Isostatic Adjustment in North America Observed by Continuous and Episodic GPS

    Science.gov (United States)

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

    2003-12-01

    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 because of the limited distribution of continuous GPS sites in and around Hudson Bay, the area of maximum glacial loading. In the last two years new continuous GPS sites have been established in Canada, but they are presently of limited use due to their short time series. Episodic GPS 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 episodic GPS data. We present data from over 100 continuous GPS sites throughout North America and more than 40 GPS sites of the Canadian Base Network (CBN). The CBN sites located across central and southern Canada have been episodically occupied between 1994 and 2002. We have detected 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. A three-dimensional site velocity distribution may permit assessment of the role of GIA in the seismicity of eastern North America.

  14. Miniaturized GPS/MEMS IMU integrated board

    Science.gov (United States)

    Lin, Ching-Fang (Inventor)

    2012-01-01

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

  15. GPS/MEMS IMU/Microprocessor Board for Navigation

    Science.gov (United States)

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

    2009-01-01

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

  16. Utilization of GPS Tropospheric Delays for Climate Research

    Science.gov (United States)

    Suparta, Wayan

    2017-05-01

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

  17. Software for a GPS-Reflection Remote-Sensing System

    Science.gov (United States)

    Lowe, Stephen

    2003-01-01

    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).

  18. Android App Based Vehicle Tracking Using GPS And GSM

    Directory of Open Access Journals (Sweden)

    Jessica Saini

    2017-09-01

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

  19. GPS/GNSS Antenna Characterization : GPS-ABC Workshop V RTCA Washington, DC October 14, 2016.

    Science.gov (United States)

    2016-10-14

    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...

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

    Data.gov (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...

  1. The GPS Laser Retroreflector Array Project

    Science.gov (United States)

    Merkowitz, Stephen M.

    2012-01-01

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

  2. GPS-KOMPAS NA MOBILNI NAPRAVI

    OpenAIRE

    Bokan, Samo

    2011-01-01

    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...

  3. Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver

    Science.gov (United States)

    Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.

    2012-01-01

    Global Positioning System (GPS)-based navigation has become common for low-Earth orbit spacecraft as the signal environment is similar to that on the Earth s surface. The situation changes abruptly, however, for spacecraft whose orbital altitudes exceed that of the GPS constellation. Visibility is dramatically reduced and signals that are present may be very weak and more susceptible to interference. GPS receivers effective at these altitudes require increased sensitivity, which often requires a high-gain antenna. Pointing such an antenna can pose a challenge. One efficient approach to mitigate these problems is the use of a digitally steered antenna array. Such an antenna can optimally allocate gain toward desired signal sources and away from interferers. This paper presents preliminary results in the development and test of a digitally steered antenna array for the Navigator GPS research program at NASA s Goddard Space Flight Center. In particular, this paper highlights the development of an array and front-end electronics, the development and test of a real-time software GPS receiver, and implementation of three beamforming methods for combining the signals from the array. Additionally, this paper discusses the development of a GPS signal simulator which produces digital samples of the GPS L1C/A signals as they would be received by an arbitrary antenna array configuration. The simulator models transmitter and receiver dynamics, near-far and multipath interference, and has been a critical component in both the development and test of the GPS receiver. The GPS receiver system was tested with real and simulated GPS signals. Preliminary results show that performance improvement was achieved in both the weak signal and interference environments, matching analytical predictions. This paper summarizes our initial findings and discusses the advantages and limitations of the antenna array and the various beamforming methods.

  4. Volcano monitoring using GPS: Developing data analysis strategies based on the June 2007 Kīlauea Volcano intrusion and eruption

    Science.gov (United States)

    Larson, Kristine M.; Poland, Michael; Miklius, Asta

    2010-01-01

    The global positioning system (GPS) is one of the most common techniques, and the current state of the art, used to monitor volcano deformation. In addition to slow (several centimeters per year) displacement rates, GPS can be used to study eruptions and intrusions that result in much larger (tens of centimeters over hours-days) displacements. It is challenging to resolve precise positions using GPS at subdaily time intervals because of error sources such as multipath and atmospheric refraction. In this paper, the impact of errors due to multipath and atmospheric refraction at subdaily periods is examined using data from the GPS network on Kīlauea Volcano, Hawai'i. Methods for filtering position estimates to enhance precision are both simulated and tested on data collected during the June 2007 intrusion and eruption. Comparisons with tiltmeter records show that GPS instruments can precisely recover the timing of the activity.

  5. Human Factors and Operations Issues in GPS and WAAS Sensor Approvals A Review and Comparison of FAA and RTCA Documents

    Science.gov (United States)

    1997-07-01

    This report is the culmination of the first task in a project to evaluate human factors and operations issues associated : with the integration of Class C Global Positioning System (GPS) sensors and Class Beta GPS/Wide Area Augmentation System : (WAA...

  6. Human factors and operations issues in GPS and WAAS sensor approvals : a review and comparison of FAA and RTCA documents

    Science.gov (United States)

    1997-07-01

    This report is the culmination of the first task in a project to evaluate human factors and operations issues associated with the integration of Class C Global Positioning System (GPS) sensors and Class Beta GPS/Wide Area Augmentation System (WAAS) s...

  7. Validating One-on-One GPS Instruction Methodology for Natural Resource Area Assessments Using Forestry Undergraduate Students

    Science.gov (United States)

    Unger, Daniel R.

    2014-01-01

    Undergraduate students pursuing a Bachelor of Science in Forestry (BSF) at Stephen F. Austin State University (SFA) attend an intensive 6-week residential hands-on instruction in applied field methods. The intensive 6-week instruction includes learning how to use the Global Positioning System (GPS) with a Garmin eTrex HCx GPS unit to accurately…

  8. Development of soil compaction analysis software (SCAN) integrating a low cost GPS receiver and compactometer.

    Science.gov (United States)

    Hwang, Jinsang; Yun, Hongsik; Kim, Juhyong; Suh, Yongcheol; Hong, Sungnam; Lee, Dongha

    2012-01-01

    A software for soil compaction analysis (SCAN) has been developed for evaluating the compaction states using the data from the GPS as well as a compactometer attached on the roller. The SCAN is distinguished from other previous software for intelligent compaction (IC) in that it can use the results from various types of GPS positioning methods, and it also has an optimal structure for remotely managing the large amounts of data gathered from numerous rollers. For this, several methods were developed: (1) improving the accuracy of low cost GPS receiver's positioning results; (2) modeling the trajectory of a moving roller using a GPS receiver's results and linking it with the data from the compactometer; and (3) extracting the information regarding the compaction states of the ground from the modeled trajectory, using spatial analysis methods. The SCAN was verified throughout various field compaction tests, and it has been confirmed that it can be a very effective tool in evaluating field compaction states.

  9. Effect of reference stations on continuous GPS (CGPS) time series

    Science.gov (United States)

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

    2004-12-01

    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.

  10. METHOD OF MAXIMAL INFORMATIVE ZONE FOR VIRTUAL REFERENCE STATION DEVELOPMENT IN KINEMATIC SYSTEMS OF GPS NETWORKS

    Directory of Open Access Journals (Sweden)

    R. A. Eminov,

    2013-03-01

    Full Text Available The existing actual material on experimental assessment of positioning error in VRS GPS networks is analyzed where the mobile receiver is provided with virtual reference station. The method of highly informative zone is suggested for removal of initial uncertainty in reference station selection with the aim to develop minimal GPS network consisting of three reference stations. Methodical recommendations and directions are given for the suggested method application.

  11. Synchronised Encoding of GPS NMEA Messages onto Hig h Definition Video Streams

    OpenAIRE

    Lewis, Paul; Winstanley, Adam C.; McCarthy, Tim

    2007-01-01

    Consumer awareness and retail penetration of high definition (HD) technologies has increased dramatically over the last few years. This has led not only to increased interest and expectation of these technologies but also affordability of equipment. Global Positioning Systems (GPS) have also seen a very dramatic increase in consumer exposure and affordability with in car navigation systems, as an example, becoming more common place. The integration of HD Video (HDV) and GPS offers new researc...

  12. Stigma and GPs' perceptions of dementia

    NARCIS (Netherlands)

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

    2016-01-01

    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

  13. Wave measurements using GPS velocity signals.

    Science.gov (United States)

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

    2011-01-01

    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.

  14. GPS queues with heterogeneous traffic classes

    NARCIS (Netherlands)

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

    2002-01-01

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

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

    National Research Council Canada - National Science Library

    Richard M. Allen; Alon Ziv

    2011-01-01

      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...

  16. New method of GPS orbit determination from GCPS network for the purpose of DOP calculations

    Directory of Open Access Journals (Sweden)

    Aly M. El-naggar

    2012-06-01

    Full Text Available The accuracy of GPS measurement satisfies the requirements of some applications, but many applications require an improvement of GPS measurement accuracy. For precise positioning by GPS, it is necessary to perform GPS mission planning. The GPS mission planning is a pre-survey task in which the values of Dilution Of Precision (DOP should be predicted for the observation points, this task should determine the best observation periods which meet the project requirements. The main purpose of this work is to study a rather simple but still fairly accurate algorithm to determine the artificial satellite orbits for the purpose of DOP calculation. The orbit determination algorithm proposed in this paper is implemented by using several reference stations and calculated the orbits by new algorithm; inverse GPS. Inverse GPS means that reference stations are considered as satellites and satellite as receiver. This new algorithm used to calculate the satellite orbit which is mainly used to calculate the DOP. A comparison is done between the estimated PDOP by using satellite coordinates from new method and from the SP3 (Standard Product # 3 file.

  17. What is the problem with medically unexplained symptoms for GPs? A meta-synthesis of qualitative studies.

    Science.gov (United States)

    Johansen, May-Lill; Risor, Mette Bech

    2017-04-01

    To gain a deeper understanding of challenges faced by GPs when managing patients with MUS. We used meta-ethnography to synthesize qualitative studies on GPs' perception and management of MUS. The problem with MUS for GPs is the epistemological incongruence between dominant disease models and the reality of meeting patients suffering from persistent illness. GPs have used flexible approaches to manage the situation, yet patients and doctors have had parallel negative experiences of being stuck, untrustworthy and helpless. In the face of cognitive incongruence, GPs have strived to achieve relational congruence with their patients. This has led to parallel positive experiences of mutual trust and validation. With more experience, some GPs seem to overcome the incongruences, and later studies point towards a reframing of the MUS problem. For GPs, the challenge with MUS is most importantly at an epistemological level. Hence, a full reframing of the problem of MUS for GPs (and for patients) implies broad changes in basic medical knowledge and education. Short-term: Improve management of patients with MUS by transferring experience-based, reality-adjusted knowledge from senior GPs to juniors. Long-term: Work towards new models of disease that integrate knowledge from all relevant disciplines. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Application of a wearable GPS unit for examining interindividual distances in a herd of Thoroughbred dams and their foals.

    Science.gov (United States)

    Sato, Fumio; Tanabe, Tomoki; Murase, Harutaka; Tominari, Masataka; Kawai, Masahito

    2017-01-01

    Global positioning system (GPS) units are now lightweight and compact. They have proven useful for analyzing the behavioral characteristics of horses in pastures. Because the GPS records data in latitude and longitude, it may be feasible to calculate the distance between GPS units. The present study aimed to confirm the applicability of GPS units in behavioral studies on horses. For this, we analyzed the accuracy of the distances calculated from GPS units using Hubeny's distance formula and of the monthly changes in interindividual distances obtained from GPS units worn by Thoroughbred dams and their foals in a pasture until weaning. The calculated inter-GPS distances were highly accurate. The regression line was linear, and the squared correlation coefficient (r2) was 0.9998. During the first month of age, the interindividual dam-dam and foal-foal distances were significantly greater than the dam-foal distance. During the second month of age, the dam-foal distance increased once and gradually decreased up to the fifth month of age. During the sixth month of age, the dam-foal distance was significantly greater than the foal-foal distance. The GPS distances calculated using Hubeny's distance formula were useful for analyzing changes in interindividual distances in a herd of Thoroughbred dams and their foals. Most likely, calculation of the distance between GPS units worn on equine head collars is likely to become a very useful tool as an objective index for quantifying equine behavioral observations.

  19. Application of a wearable GPS unit for examining interindividual distances in a herd of Thoroughbred dams and their foals

    Science.gov (United States)

    SATO, Fumio; TANABE, Tomoki; MURASE, Harutaka; TOMINARI, Masataka; KAWAI, Masahito

    2017-01-01

    ABSTRACT Global positioning system (GPS) units are now lightweight and compact. They have proven useful for analyzing the behavioral characteristics of horses in pastures. Because the GPS records data in latitude and longitude, it may be feasible to calculate the distance between GPS units. The present study aimed to confirm the applicability of GPS units in behavioral studies on horses. For this, we analyzed the accuracy of the distances calculated from GPS units using Hubeny’s distance formula and of the monthly changes in interindividual distances obtained from GPS units worn by Thoroughbred dams and their foals in a pasture until weaning. The calculated inter-GPS distances were highly accurate. The regression line was linear, and the squared correlation coefficient (r2) was 0.9998. During the first month of age, the interindividual dam–dam and foal–foal distances were significantly greater than the dam–foal distance. During the second month of age, the dam–foal distance increased once and gradually decreased up to the fifth month of age. During the sixth month of age, the dam–foal distance was significantly greater than the foal–foal distance. The GPS distances calculated using Hubeny’s distance formula were useful for analyzing changes in interindividual distances in a herd of Thoroughbred dams and their foals. Most likely, calculation of the distance between GPS units worn on equine head collars is likely to become a very useful tool as an objective index for quantifying equine behavioral observations. PMID:28400702

  20. Near real-time GPS applications for tsunami early warning systems

    Directory of Open Access Journals (Sweden)

    C. Falck

    2010-02-01

    Full Text Available GPS (Global Positioning System technology is widely used for positioning applications. Many of them have high requirements with respect to precision, reliability or fast product delivery, but usually not all at the same time as it is the case for early warning applications. The tasks for the GPS-based components within the GITEWS project (German Indonesian Tsunami Early Warning System, Rudloff et al., 2009 are to support the determination of sea levels (measured onshore and offshore and to detect co-seismic land mass displacements with the lowest possible latency (design goal: first reliable results after 5 min. The completed system was designed to fulfil these tasks in near real-time, rather than for scientific research requirements. The obtained data products (movements of GPS antennas are supporting the warning process in different ways. The measurements from GPS instruments on buoys allow the earliest possible detection or confirmation of tsunami waves on the ocean. Onshore GPS measurements are made collocated with tide gauges or seismological stations and give information about co-seismic land mass movements as recorded, e.g., during the great Sumatra-Andaman earthquake of 2004 (Subarya et al., 2006. This information is important to separate tsunami-caused sea height movements from apparent sea height changes at tide gauge locations (sensor station movement and also as additional information about earthquakes' mechanisms, as this is an essential information to predict a tsunami (Sobolev et al., 2007.

    This article gives an end-to-end overview of the GITEWS GPS-component system, from the GPS sensors (GPS receiver with GPS antenna and auxiliary systems, either onshore or offshore to the early warning centre displays. We describe how the GPS sensors have been installed, how they are operated and the methods used to collect, transfer and process the GPS data in near real-time. This includes the sensor system design, the communication

  1. Real-time multi-GNSS single-frequency precise point positioning

    NARCIS (Netherlands)

    de Bakker, P.F.; Tiberius, C.C.J.M.

    2017-01-01

    Precise Point Positioning (PPP) is a popular Global Positioning System (GPS) processing strategy, thanks to its high precision without requiring additional GPS infrastructure. Single-Frequency PPP (SF-PPP) takes this one step further by no longer relying on expensive dual-frequency GPS receivers,

  2. GPS sledovací systém

    OpenAIRE

    Hofman, Jan

    2010-01-01

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

  3. Guidance simulation and test support for differential GPS flight experiment

    Science.gov (United States)

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

    1987-01-01

    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.

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

    Science.gov (United States)

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

    2010-09-01

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

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

    Science.gov (United States)

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

    2017-01-01

    Global Positioning System (GPS) tags are nowadays widely used in wildlife tracking. This geolocation technique can suffer from fix loss biases due to poor satellite GPS geometry, that result in tracking data gaps leading to wrong research conclusions. In addition, new solar-powered GPS tags deployed on birds can suffer from a new "battery drain bias" currently ignored in movement ecology analyses. We use a GPS tracking dataset of bearded vultures (Gypaetus barbatus), tracked for several years with solar GPS tags, to evaluate the causes and triggers of fix and data retrieval loss biases. We compare two models of solar GPS tags using different data retrieval systems (Argos vs GSM-GPRS), and programmed with different duty cycles. Neither of the models was able to accomplish the duty cycle programed initially. Fix and data retrieval loss rates were always greater than expected, and showed non-random gaps in GPS locations. Number of fixes per month of tracking was a bad criterion to identify tags with smaller biases. Fix-loss rates were four times higher due to battery drain than due to poor GPS satellite geometry. Both tag models were biased due to the uneven solar energy available for the recharge of the tag throughout the annual cycle, resulting in greater fix-loss rates in winter compared to summer. In addition, we suggest that the bias found along the diurnal cycle is linked to a complex three-factor interaction of bird flight behavior, topography and fix interval. More fixes were lost when vultures were perching compared to flying, in rugged versus flat topography. But long fix-intervals caused greater loss of fixes in dynamic (flying) versus static situations (perching). To conclude, we emphasize the importance of evaluating fix-loss bias in current tracking projects, and deploying GPS tags that allow remote duty cycle updates so that the most appropriate fix and data retrieval intervals can be selected.

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

    Directory of Open Access Journals (Sweden)

    Rafa Silva

    Full Text Available Global Positioning System (GPS tags are nowadays widely used in wildlife tracking. This geolocation technique can suffer from fix loss biases due to poor satellite GPS geometry, that result in tracking data gaps leading to wrong research conclusions. In addition, new solar-powered GPS tags deployed on birds can suffer from a new "battery drain bias" currently ignored in movement ecology analyses. We use a GPS tracking dataset of bearded vultures (Gypaetus barbatus, tracked for several years with solar GPS tags, to evaluate the causes and triggers of fix and data retrieval loss biases. We compare two models of solar GPS tags using different data retrieval systems (Argos vs GSM-GPRS, and programmed with different duty cycles. Neither of the models was able to accomplish the duty cycle programed initially. Fix and data retrieval loss rates were always greater than expected, and showed non-random gaps in GPS locations. Number of fixes per month of tracking was a bad criterion to identify tags with smaller biases. Fix-loss rates were four times higher due to battery drain than due to poor GPS satellite geometry. Both tag models were biased due to the uneven solar energy available for the recharge of the tag throughout the annual cycle, resulting in greater fix-loss rates in winter compared to summer. In addition, we suggest that the bias found along the diurnal cycle is linked to a complex three-factor interaction of bird flight behavior, topography and fix interval. More fixes were lost when vultures were perching compared to flying, in rugged versus flat topography. But long fix-intervals caused greater loss of fixes in dynamic (flying versus static situations (perching. To conclude, we emphasize the importance of evaluating fix-loss bias in current tracking projects, and deploying GPS tags that allow remote duty cycle updates so that the most appropriate fix and data retrieval intervals can be selected.

  7. Investigation into the Effect of Atmospheric Particulate Matter (PM2.5 and PM10) Concentrations on GPS Signals.

    Science.gov (United States)

    Lau, Lawrence; He, Jun

    2017-03-03

    The Global Positioning System (GPS) has been widely used in navigation, surveying, geophysical and geodynamic studies, machine guidance, etc. High-precision GPS applications such as geodetic surveying need millimeter and centimeter level accuracy. Since GPS signals are affected by atmospheric effects, methods of correcting or eliminating ionospheric and tropospheric bias are needed in GPS data processing. Relative positioning can be used to mitigate the atmospheric effect, but its efficiency depends on the baseline lengths. Air pollution is a serious problem globally, especially in developing countries that causes health problems to humans and damage to the ecosystem. Respirable suspended particles are coarse particles with a diameter of 10 micrometers or less, also known as PM10. Moreover, fine particles with a diameter of 2.5 micrometers or less are known as PM2.5. GPS signals travel through the atmosphere before arriving at receivers on the Earth's surface, and the research question posed in this paper is: are GPS signals affected by the increased concentration of the PM2.5/PM10 particles? There is no standard model of the effect of PM2.5/PM10 particles on GPS signals in GPS data processing, although an approximate generic model of non-gaseous atmospheric constituents (GPS signals and validates the aforementioned approximate model with a carrier-to-noise ratio (CNR)-based empirical method. Both the approximate model and the empirical results show that the atmospheric PM2.5/PM10 particles and their concentrations have a negligible effect on GPS signals and the effect is comparable with the noise level of GPS measurements.

  8. Investigation into the Effect of Atmospheric Particulate Matter (PM2.5 and PM10 Concentrations on GPS Signals

    Directory of Open Access Journals (Sweden)

    Lawrence Lau

    2017-03-01

    Full Text Available The Global Positioning System (GPS has been widely used in navigation, surveying, geophysical and geodynamic studies, machine guidance, etc. High-precision GPS applications such as geodetic surveying need millimeter and centimeter level accuracy. Since GPS signals are affected by atmospheric effects, methods of correcting or eliminating ionospheric and tropospheric bias are needed in GPS data processing. Relative positioning can be used to mitigate the atmospheric effect, but its efficiency depends on the baseline lengths. Air pollution is a serious problem globally, especially in developing countries that causes health problems to humans and damage to the ecosystem. Respirable suspended particles are coarse particles with a diameter of 10 micrometers or less, also known as PM10. Moreover, fine particles with a diameter of 2.5 micrometers or less are known as PM2.5. GPS signals travel through the atmosphere before arriving at receivers on the Earth’s surface, and the research question posed in this paper is: are GPS signals affected by the increased concentration of the PM2.5/PM10 particles? There is no standard model of the effect of PM2.5/PM10 particles on GPS signals in GPS data processing, although an approximate generic model of non-gaseous atmospheric constituents (<1 mm can be found in the literature. This paper investigates the effect of the concentration of PM2.5/PM10 particles on GPS signals and validates the aforementioned approximate model with a carrier-to-noise ratio (CNR-based empirical method. Both the approximate model and the empirical results show that the atmospheric PM2.5/PM10 particles and their concentrations have a negligible effect on GPS signals and the effect is comparable with the noise level of GPS measurements.

  9. GPs' use of problem solving therapy for depression: a qualitative study of barriers to and enablers of evidence based care

    Directory of Open Access Journals (Sweden)

    Gunn Jane

    2007-04-01

    Full Text Available Abstract Background Depression is a major health concern, predominantly treated by general practitioners (GPs. Problem solving therapy (PST is recognised as an effective treatment for depression that is not widely used by GPs. This research aims to explore barriers and enablers that may influence GPs use of this treatment. Method Qualitative methodology was used including individual and focus group interviews of GPs, PST experts and consumers. Analysis was undertaken using the Theory of Planned Behaviour (TPB as a framework. Results A spectrum of potential influences, on GPs' use of PST emerged. Both barriers and enablers were identified. PST was perceived as being close to current practice approaches and potentially beneficial to both doctor and patient. In addition to a broadly positive attitude to PST, expressed by those with previous experience of its use, potential solutions to perceived barriers emerged. By contrast some GPs expressed fear that the use of PST would result in loss of doctor control of consultations and associated potential adverse patient outcomes. Patient expectations, which emerged as not always coinciding with GPs' perception of those expectations, were identified as a potential influence on GPs' decision concerning adoption of PST. In addition specific factors, including GP skill and confidence, consultation time constraints and technical issues related to PST were noted as potential concerns. Conclusion This research contributes to our knowledge of the factors that may influence GPs' decisions regarding use of PST as a treatment for depression. It recognises both barriers and enablers. It suggests that for many GPs, PST is viewed in a positive light, providing encouragement to those seeking to increase the provision of PST by GPs. In identifying a number of potential barriers, along with associated options to address many of these barriers, it provides insights which may assist in the planning of GP training in PST.

  10. Group delay variations of GPS transmitting and receiving antennas

    Science.gov (United States)

    Wanninger, Lambert; Sumaya, Hael; Beer, Susanne

    2017-09-01

    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.

  11. Developing Digital Privacy: Children's Moral Judgments Concerning Mobile GPS Devices.

    Science.gov (United States)

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

    2017-05-07

    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.

  12. WegenerNet 1km-scale sub-daily rainfall data and their application: a hydrological modeling study on the sensitivity of small-catchment runoff to spatial rainfall variability

    Science.gov (United States)

    Oh, Sungmin; Hohmann, Clara; Foelsche, Ulrich; Fuchsberger, Jürgen; Rieger, Wolfgang; Kirchengast, Gottfried

    2017-04-01

    WegenerNet Feldbach region (WEGN), a pioneering experiment for weather and climate observations, has recently completed its first 10-year precipitation measurement cycle. The WEGN has measured precipitation, temperature, humidity, and other parameters since the beginning of 2007, supporting local-level monitoring and modeling studies, over an area of about 20 km x 15 km centered near the City of Feldbach (46.93 ˚ N, 15.90 ˚ E) in the Alpine forelands of southeast Austria. All the 151 stations in the network are now equipped with high-quality Meteoservis sensors as of August 2016, following an equipment with Friedrichs sensors at most stations before, and continue to provide high-resolution (2 km2/5-min) gauge based precipitation measurements for interested users in hydro-meteorological communities. Here we will present overall characteristics of the WEGN, with a focus on sub-daily precipitation measurements, from the data processing (data quality control, gridded data products generation, etc.) to data applications (e.g., ground validation of satellite estimates). The latter includes our recent study on the propagation of uncertainty from rainfall to runoff. The study assesses responses of small-catchment runoff to spatial rainfall variability in the WEGN region over the Raab valley, using a physics-based distributed hydrological model; Water Flow and Balance Simulation Model (WaSiM), developed at ETH Zurich (Schulla, ETH Zurich, 1997). Given that uncertainty due to resolution of rainfall measurements is believed to be a significant source of error in hydrologic modeling especially for convective rainfall that dominates in the region during summer, the high-resolution of WEGN data furnishes a great opportunity to analyze effects of rainfall events on the runoff at different spatial resolutions. Furthermore, the assessment can be conducted not only for the lower Raab catchment (area of about 500 km2) but also for its sub-catchments (areas of about 30-70 km2

  13. Comparison of the Stochastic Models for Double-Differenced GPS Measurements

    Directory of Open Access Journals (Sweden)

    Dudy Darmawan

    2004-11-01

    Full Text Available Double-differenced GPS carrier phase measurements are commonly used in GPS precise positioning applications and processed with algorithms based on the least-squares (LS principle. In order to apply the LS principle, one needs to define properly both the functional and stochastic models. Whilst the functional model for precise GPS positioning is sufficiently well known, realistic stochastic modeling is still a difficult task to accomplish in practice. Incorrect stochastic models for double-differenced GPS measurements will lead to unreliable estimates for ambiguity resolution and, eventually, it will bias positioning results. The common assumption when we construct the stochastic model is that all raw GPS measurements are independent and have the same variances. In fact, this is not realistic, since due to varying noise levels measurements obtained from different GPS satellites cannot have the same accuracy. A realistic stochastic modeling should be able to capture the ordinary noises in the observables. In order to specify a realistic stochastic model for precise relative GPS positioning applications, in this paper the performance of three stochastic models namely the commonly used model or the standard model, the outer product of residual data vector model and Minimum Norm Quadratic Unbiased Estimation (MINQUE are examined and effects of each the proposed model on statistic for ambiguity search and positioning accuracy are compared. The results indicate that the MINQUE model tends to perform better than the other models. Using the MINQUE model, the reliability of the ambiguity resolution and the statistics of the baseline components can be improved. It may suggest that the MINQUE model, which is based on modern statistical theory, is capable of capturing the ordinary noises.

  14. Precise Relative Positioning of Formation Flying Spacecraft using GPS

    NARCIS (Netherlands)

    Kroes, R.

    2006-01-01

    Spacecraft formation flying is considered as a key technology for advanced space missions. Compared to large individual spacecraft, the distribution of sensor systems amongst multiple platforms offers improved flexibility, shorter times to mission, and the prospect of being more cost effective.

  15. Observation of Earth's free oscillation by dense GPS array: after the 2011 Tohoku megathrust earthquake.

    Science.gov (United States)

    Mitsui, Yuta; Heki, Kosuke

    2012-01-01

    Day-scale Earth's free oscillation after large earthquakes has been detected by underground instruments such as strainmeters, gravimeters and seismometers, to investigate Earth's internal structure, geodynamics, and source properties of earthquakes. Here we show that Global Positioning System (GPS) can also detect the signals of the Earth's free oscillation. A dense GPS array in Japan (GEONET) recorded the surface deformation following the 2011 Tohoku megathrust earthquake. A simple array analysis over 300 stations reduces local noise in GPS time series. We find that the dense GPS array truly detected both spheroidal and toroidal fundamental modes in three-direction displacement. This new tool has a strong potential to investigate the free oscillations particularly in low-frequency bands.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature...... behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS...... occultations with CALIPSO profiles over deep convection. Results show a sharp spike in GPS bending angle highly correlated to the top of the clouds, corresponding to anomalously cold temperatures within the clouds. Above the clouds the temperatures return to background conditions, and there is a strong...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature...... behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS...... occultations with CALIPSO profiles over deep convection. Results show a sharp spike in GPS bending angle highly correlated to the top of the clouds, corresponding to anomalously cold temperatures within the clouds. Above the clouds the temperatures return to background conditions, and there is a strong...

  18. A RLS-SVM Aided Fusion Methodology for INS during GPS Outages

    Science.gov (United States)

    Yao, Yiqing; Xu, Xiaosu

    2017-01-01

    In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS) outages, a novel robust least squares support vector machine (LS-SVM)-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS). The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics. PMID:28245549

  19. A RLS-SVM Aided Fusion Methodology for INS during GPS Outages

    Directory of Open Access Journals (Sweden)

    Yiqing Yao

    2017-02-01

    Full Text Available In order to maintain a relatively high accuracy of navigation performance during global positioning system (GPS outages, a novel robust least squares support vector machine (LS-SVM-aided fusion methodology is explored to provide the pseudo-GPS position information for the inertial navigation system (INS. The relationship between the yaw, specific force, velocity, and the position increment is modeled. Rather than share the same weight in the traditional LS-SVM, the proposed algorithm allocates various weights for different data, which makes the system immune to the outliers. Field test data was collected to evaluate the proposed algorithm. The comparison results indicate that the proposed algorithm can effectively provide position corrections for standalone INS during the 300 s GPS outage, which outperforms the traditional LS-SVM method. Historical information is also involved to better represent the vehicle dynamics.

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

    Science.gov (United States)

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

    2015-03-01

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

  1. Error Analysis of Determining Airplane Location by Global Positioning System

    OpenAIRE

    Hajiyev, Chingiz; Burat, Alper

    1999-01-01

    This paper studies the error analysis of determining airplane location by global positioning system (GPS) using statistical testing method. The Newton Rhapson method positions the airplane at the intersection point of four spheres. Absolute errors, relative errors and standard deviation have been calculated The results show that the positioning error of the airplane varies with the coordinates of GPS satellite and the airplane.

  2. The validity and reliability of GPS units for measuring distance in team sport specific running patterns.

    Science.gov (United States)

    Jennings, Denise; Cormack, Stuart; Coutts, Aaron J; Boyd, Luke; Aughey, Robert J

    2010-09-01

    To assess the validity and reliability of distance data measured by global positioning system (GPS) units sampling at 1 and 5 Hz during movement patterns common to team sports. Twenty elite Australian Football players each wearing two GPS devices (MinimaxX, Catapult, Australia) completed straight line movements (10, 20, 40 m) at various speeds (walk, jog, stride, sprint), changes of direction (COD) courses of two different frequencies (gradual and tight), and a team sport running simulation circuit. Position and speed data were collected by the GPS devices at 1 and 5 Hz. Distance validity was assessed using the standard error of the estimate (±90% confidence intervals [CI]). Reliability was estimated using typical error (TE) ± 90% CI (expressed as coefficient of variation [CV]). Measurement accuracy decreased as speed of locomotion increased in both straight line and the COD courses. Difference between criterion and GPS measured distance ranged from 9.0% to 32.4%. A higher sampling rate improved validity regardless of distance and locomotion in the straight line, COD and simulated running circuit trials. The reliability improved as distance traveled increased but decreased as speed increased. Total distance over the simulated running circuit exhibited the lowest variation (CV 3.6%) while sprinting over 10 m demonstrated the highest (CV 77.2% at 1 Hz). Current GPS systems maybe limited for assessment of short, high speed straight line running and efforts involving change of direction. An increased sample rate improves validity and reliability of GPS devices.

  3. PFISR GPS tracking mode for researching high-latitude ionospheric electron density gradients associated with GPS scintillation

    Science.gov (United States)

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

    2016-12-01

    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.

  4. Application of GPS Measurements for Ionospheric and Tropospheric Modelling

    Science.gov (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

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

    Directory of Open Access Journals (Sweden)

    E Chavoshi

    2016-04-01

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

  6. 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.

    2009-07-01

    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.

  7. GPs' experiences with out-of-hours GP cooperatives: a survey study from the Netherlands.

    Science.gov (United States)

    Smits, Marleen; Keizer, Ellen; Huibers, Linda; Giesen, Paul

    2014-09-01

    Out-of-hours primary care has been provided by general practitioner (GP) cooperatives since the year 2000 in the Netherlands. Early studies in countries with similar organizational structures showed positive GP experiences. However, nowadays it is said that GPs experience a high workload at the cooperative and that they outsource a considerable part of their shifts. To examine positive and negative experiences of GPs providing out-of-hours primary care, and the frequency and reasons for outsourcing shifts. A cross-sectional observational survey among 688 GPs connected to six GP cooperatives in the Netherlands, using a web-based questionnaire. The response was 55% (n = 378). The main reasons for working in GP cooperatives were to retain registration as GP (79%) and remain experienced in acute care (74%). GPs considered the peak hours (81%) and the high number of patients (73%) as the most negative aspects. Most GPs chose to provide the out-of-hours shifts themselves: 85% outsourced maximally 25% of their shifts. The percentage of outsourced shifts increased with age. Main reasons for outsourcing were the desire to have more private time (76%); the high workload in daytime practice (71%); and less the workload during out-of-hours (46%). GPs are motivated to work in out-of-hours GP cooperatives, and they outsource few shifts. GPs consider the peak load and the large number of (non-urgent) help requests as the most negative aspects. To motivate and involve GPs for 7 × 24-h primary care, it is important to set limits on their workload.

  8. TLALOCNet: A Continuous GPS-Met Array in Mexico for Seismotectonic and Atmospheric Research

    Science.gov (United States)

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

    2015-12-01

    TLALOCNet is a network of continuous Global Positioning System (cGPS) and meteorology stations in Mexico for the interrogation of the earthquake cycle, tectonic processes, land subsidence, and atmospheric processes of Mexico. Once completed, TLALOCNet will span all of Mexico and will link existing GPS infrastructure in North America and the Caribbean aiming towards creating a continuous, federated network of networks in the Americas. Phase 1 (2014-2015), funded by NSF and UNAM, is building and upgrading 30+ cGPS-Met sites to the high standard of the EarthScope Plate Boundary Observatory (PBO). Phase 2 (2016) will add ~25 more cGPS-Met stations to be funded through CONACyT. TLALOCNet provides open and freely available raw GPS data, GPS-PWV, surface meteorology measurements, time series of daily positions, as well as a station velocity field to support a broad range of geoscience investigations. This is accomplished through the development of the TLALOCNet data center (http://tlalocnet.udg.mx) that serves as a collection and distribution point. This data center is based on UNAVCO's Dataworks-GSAC software and can work as part of UNAVCO's seamless archive for discovery, sharing, and access to data.The TLALOCNet data center also contains contributed data from several regional networks in Mexico. By using the same protocols and structure as the UNAVCO and other COCONet regional data centers, the geodetic community has the capability of accessing data from a large number of scientific and academically operated Mexican GPS sites. This archive provides a fully querable and scriptable GPS and Meteorological data retrieval point. Additionally Real-time 1Hz streams from selected TLALOCNet stations are available in BINEX, RTCM 2.3 and RTCM 3.1 formats via the Networked Transport of RTCM via Internet Protocol (NTRIP).

  9. Mining significant semantic locations from GPS data

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  10. Using GPS for studying pastoral mobility

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2017-01-01

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

  11. GPS Radio Occultation as Part of the Global Observing System for Atmosphere

    Science.gov (United States)

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

    2008-01-01

    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.

  12. Airborne Antenna System for Minimum-Cycle-Slip GPS Reception

    Science.gov (United States)

    Wright, C. Wayne

    2009-01-01

    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

  13. Implementation of a GPS-RO data processing system for the KIAPS-LETKF data assimilation system

    National Research Council Canada - National Science Library

    Kwon, H; Kang, J.-S; Jo, Y; Kang, J. H

    2015-01-01

    .... As part of the KIAPS package for observation processing (KPOP) system for data assimilation, preprocessing, and quality control modules for bending-angle measurements of global positioning system radio occultation (GPS-RO...

  14. GPS measurements of crustal deformation associated with the 22 April 1991, Valle de la Estrella , Costa Rica earthquake

    Science.gov (United States)

    Lundgren, Paul R.; Wolf, Susan K.; Protti, Marino; Hurst, Kenneth J.

    1993-01-01

    Results are presented for analysis of Global Positioning System (GPS) measurements made at sites in Costa Rica in February and July 1991. Significant horizontal and vertical displacements relative to February positions were observed. Differences were found in GPS derived vertical and horizontal displacements as compared to other types of geodetic measurements of uplift in the coastal regions. A slip dislocation model which fits the GPS measured displacement was computed. Differences between these data sets and their associated models were investigated in light of unmodeled slip heterogeneity on the fault and post-seismic displacements.

  15. Vision-Based Position Estimation Utilizing an Extended Kalman Filter

    Science.gov (United States)

    2016-12-01

    GPS jammers are available for as little as $50 [1]. Even malfunctioning equipment can lead to a drone losing its position and thus aborting the...the UAV loses GPS but must maintain a relative position to the target. The drone uses the algorithm to accomplish this task. The exemplary scenario...passive measurements without using GPS . The algorithm receives an image from the drone . It locates the target in the image and outputs an angle. The

  16. Analysis and visualization of collective motion in football : Analysis of youth football using GPS and visualization of professional football

    OpenAIRE

    Rosén, Emil

    2015-01-01

    Football is one of the biggest sports in the world. Professional teams track their player's positions using GPS (Global Positioning System). This report is divided into two parts, both focusing on applying collective motion to football. % The goal of the first part was to both see if a set of cheaper GPS units could be used to analyze the collective motion of a youth football team. 15 football players did two experiments and played three versus three football matches against each other while ...

  17. GPS IIF yaw attitude control during eclipse season

    Science.gov (United States)

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

    2011-12-01

    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

  18. GPS: El sistema de posicionamiento global

    National Research Council Canada - National Science Library

    Juan Gilberto Serpas; Manuel Ramírez N; Franklin de Obaldía

    2016-01-01

    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...

  19. NGA’s Relationship with GPS

    Science.gov (United States)

    2012-08-01

    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

  20. Performance evaluation of GPS receiver under equatorial scintillation

    Directory of Open Access Journals (Sweden)

    Alison de Oliveira Moraes

    2009-06-01

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

  1. GPS Enabled Semi-Autonomous Robot

    Science.gov (United States)

    2017-09-01

    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

  2. En Billig GPS Data Analyse Platform

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  3. GPS: Public Utility or Software Platform

    Science.gov (United States)

    2016-09-01

    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

  4. Non-traditional approaches to teaching GPS online

    Science.gov (United States)

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

    2009-12-01

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

  5. Reinforced Ultra-Tightly Coupled GPS/INS System for Challenging Environment

    Directory of Open Access Journals (Sweden)

    Xueyun Wang

    2014-01-01

    Full Text Available Among all integration levels currently available for Global Positioning System (GPS and Inertial Navigation System (INS Integrated System, ultra-tightly coupled (UTC GPS/INS system is the best choice for accurate and reliable navigation. Nevertheless the performance of UTC GPS/INS system degrades in challenging environments, such as jamming, changing noise of GPS signals, and high dynamic maneuvers. When low-end Inertial Measurement Units (IMUs based on MEMS sensors are employed, the performance degradation will be more severe. To solve this problem, a reinforced UTC GPS/INS system is proposed. Two techniques are adopted to deal with jamming and high dynamics. Firstly, adaptive integration Kalman filter (IKF based on fuzzy logics is developed to reinforce the antijamming ability. The parameters of membership functions (MFs are adjusted and optimized through self-developed neutral network. Secondly, a Doppler frequency error estimator based on Kalman filter is designed to improve the navigation performance under high dynamics. A complete simulation platform is established to evaluate the reinforced system. Results demonstrate that the proposed system architecture significantly improves navigation performance in challenging environments and it is a more advanced solution to accurate and reliable navigation than traditional UTC GPS/INS system.

  6. GPS/UWB/MEMS-IMU tightly coupled navigation with improved robust Kalman filter

    Science.gov (United States)

    Li, Zengke; Chang, Guobin; Gao, Jingxiang; Wang, Jian; Hernandez, Alberto

    2016-12-01

    The integration of Global Positioning System (GPS) with Inertial Navigation System (INS) has been very intensively developed and widely applied in multiple areas. To further enhance the reliability and availability of GPS/INS integrated navigation in GPS challenging environment, range observation through ultra-wideband (UWB) is introduced in GPS/INS tightly coupled navigation. An improved robust Kalman filter is proposed and used to resist the influence of gross error from UWB observation in GPS/UWB/IMU tightly coupled navigation. The variance of the squared Mahalanobis distance in moving window is calculated, which brings as new judgement factor for gross errors in order to decrease the rate of false outlier identification. A simulation analysis shows that the improved robust Kalman filter is able to correctly identify gross errors and the rate of false judgment as zero. In order to validate the new robust filter, a real experiment is conducted. The results indicate that the improved robust Kalman filter used in GPS/UWB/INS tightly coupled navigation is able to remove the harmful effect of gross error in UWB observation. It clearly illustrates that the improved robust Kalman filter is very effective, and all the simulated small and large gross errors added to UWB distance observation are successfully identified.

  7. GPS suggests low physical activity in urban Hispanic school children: a proof of concept study.

    Science.gov (United States)

    Carrel, Aaron L; Sledge, Jeffrey S; Ventura, Stephen J; Eickhoff, Jens C; Allen, David B

    2014-01-01

    Urban environments can increase risk for development of obesity, insulin resistance (IR), and type 2 diabetes mellitus (T2DM) by limiting physical activity. This study examined, in a cohort of urban Hispanic youth, the relationship between daily physical activity (PA) measured by GPS, insulin resistance and cardiovascular fitness. Hispanic middle school children (n = 141) were assessed for body mass index (BMI), IR (homeostasis model [HOMA-IR]), cardiovascular fitness (progressive aerobic cardiovascular endurance run [PACER]). PA was measured (GPS-PA) and energy expenditure estimated (GPS-EE) utilizing a global positioning mapping device worn for up to 7 days. Students (mean age 12.7 ± 1.2 years, 52% female) spent 98% of waking time in sedentary activities, 1.7% in moderate intensity PA, and 0.3% in vigorous intensity. GPS analysis revealed extremely low amounts of physical movement during waking hours. The degree of low PA confounded correlation analysis with PACER or HOMA-IR. Levels of moderate and vigorous intensity PA, measured by GPS, were extremely low in these urban Hispanic youth, possibly contributing to high rates of obesity and IR. Physical movement patterns suggest barriers to PA in play options near home, transportation to school, and in school recess time. GPS technology can objectively and accurately evaluate initiatives designed to reduce obesity and its morbidities by increasing PA.

  8. A Performance Improvement Method for Low-Cost Land Vehicle GPS/MEMS-INS Attitude Determination

    Science.gov (United States)

    Cong, Li; Li, Ercui; Qin, Honglei; Ling, Keck Voon; Xue, Rui

    2015-01-01

    Global positioning system (GPS) technology is well suited for attitude determination. However, in land vehicle application, low-cost single frequency GPS receivers which have low measurement quality are often used, and external factors such as multipath and low satellite visibility in the densely built-up urban environment further degrade the quality of the GPS measurements. Due to the low-quality receivers used and the challenging urban environment, the success rate of the single epoch ambiguity resolution for dynamic attitude determination is usually quite low. In this paper, a micro-electro-mechanical system (MEMS)—inertial navigation system (INS)-aided ambiguity resolution method is proposed to improve the GPS attitude determination performance, which is particularly suitable for land vehicle attitude determination. First, the INS calculated baseline vector is augmented with the GPS carrier phase and code measurements. This improves the ambiguity dilution of precision (ADOP), resulting in better quality of the unconstrained float solution. Second, the undesirable float solutions caused by large measurement errors are further filtered and replaced using the INS-aided ambiguity function method (AFM). The fixed solutions are then obtained by the constrained least squares ambiguity decorrelation (CLAMBDA) algorithm. Finally, the GPS/MEMS-INS integration is realized by the use of a Kalman filter. Theoretical analysis of the ADOP is given and experimental results demonstrate that our proposed method can significantly improve the quality of the float ambiguity solution, leading to high success rate and better accuracy of attitude determination. PMID:25760057

  9. Performance Evaluation of Block Acquisition and Tracking Algorithms Using an Open Source GPS Receiver Platform

    Science.gov (United States)

    Ramachandran, Ganesh K.; Akopian, David; Heckler, Gregory W.; Winternitz, Luke B.

    2011-01-01

    Location technologies have many applications in wireless communications, military and space missions, etc. US Global Positioning System (GPS) and other existing and emerging Global Navigation Satellite Systems (GNSS) are expected to provide accurate location information to enable such applications. While GNSS systems perform very well in strong signal conditions, their operation in many urban, indoor, and space applications is not robust or even impossible due to weak signals and strong distortions. The search for less costly, faster and more sensitive receivers is still in progress. As the research community addresses more and more complicated phenomena there exists a demand on flexible multimode reference receivers, associated SDKs, and development platforms which may accelerate and facilitate the research. One of such concepts is the software GPS/GNSS receiver (GPS SDR) which permits a facilitated access to algorithmic libraries and a possibility to integrate more advanced algorithms without hardware and essential software updates. The GNU-SDR and GPS-SDR open source receiver platforms are such popular examples. This paper evaluates the performance of recently proposed block-corelator techniques for acquisition and tracking of GPS signals using open source GPS-SDR platform.

  10. Precipitable Water Vapor Estimates in the Australian Region from Ground-Based GPS Observations

    Directory of Open Access Journals (Sweden)

    Suelynn Choy

    2015-01-01

    Full Text Available We present a comparison of atmospheric precipitable water vapor (PWV derived from ground-based global positioning system (GPS receiver with traditional radiosonde measurement and very long baseline interferometry (VLBI technique for a five-year period (2008–2012 using Australian GPS stations. These stations were selectively chosen to provide a representative regional distribution of sites while ensuring conventional meteorological observations were available. Good agreement of PWV estimates was found between GPS and VLBI comparison with a mean difference of less than 1 mm and standard deviation of 3.5 mm and a mean difference and standard deviation of 0.1 mm and 4.0 mm, respectively, between GPS and radiosonde measurements. Systematic errors have also been discovered during the course of this study, which highlights the benefit of using GPS as a supplementary atmospheric PWV sensor and calibration system. The selected eight GPS sites sample different climates across Australia covering an area of approximately 30° NS/EW. It has also shown that the magnitude and variation of PWV estimates depend on the amount of moisture in the atmosphere, which is a function of season, topography, and other regional climate conditions.

  11. GPS Signal Scattering from Sea Surface: Wind Speed Retrieval Using Experimental Data and Theoretical Model

    Science.gov (United States)

    Komjathy, Attila; Zavorotny, Valery U.; Axelrad, Penina; Born, George H.; Garrison, James L.

    2000-01-01

    Global Positioning System (GPS) signals reflected from the ocean surface have potential use for various remote sensing purposes. Some possibilities arc measurements of surface roughness characteristics from which ware height, wind speed, and direction could be determined. For this paper, GPS-reflected signal measurements collected at aircraft altitudes of 2 km to 5 km with a delay-Doppler mapping GPS receiver arc used to explore the possibility of determining wind speed. To interpret the GPS data, a theoretical model has been developed that describes the power of the reflected GPS signals for different time delays and Doppler frequencies as a function of geometrical and environmental parameters. The results indicate a good agreement between the measured and the modeled normalized signal power waveforms during changing surface wind conditions. The estimated wind speed using surface- reflected GPS data, obtained by comparing actual and modeled waveforms, shows good agreement (within 2 m/s) with data obtained from a nearby buoy and independent wind speed measurements derived from the TOPEX/Poseidon altimetric satellite.

  12. Ionospheric scintillation detection based on GPS observations, a case study over Iran

    Science.gov (United States)

    Sobhkhiz Miandehi, Sahar; Alizadeh Elizei, M. Mahdi; Schuh, Harald

    2017-04-01

    Global Positioning System (GPS) which is used extensively for various purposes such as navigation, surveying, remote sensing and telecommunication, is strongly affected by the earth's upper atmosphere, the ionosphere. Ionosphere is a highly variable region with complex physical characteristics in which the density of free electrons are large enough to have considerable effects on signals' propagation travelling through this dispersive medium. As GPS signals travel through the ionosphere, they may experience rapid amplitude fluctuations or unexpected phase changes. This is referred to as ionospheric scintillation. Ionospheric scintillation which is caused by small scale irregularities in the electron density, is one of the dominant propagation disturbances at radio frequency signals. These irregularities severely affect the accuracy and reliability of GPS measurements. Therefore it is necessary to investigate ionospheric scintillation and its effects on GPS observations. The focus of this paper is to detect ionospheric scintillations over Iran's region, during different periods of solar activity and to investigate these effects on GPS observations in more detail. Furthermore the effects of these irregularities on regional modeling of ionosphere over Iran is also investigated. The results show that effectiveness of this phenomenon depends on geographic location, local time and global geomagnetic storm index (kp index). The required data for this investigation are ground based measurements of permanent GPS stations over Iran, established by the National Cartographic Center of Iran (NCC).

  13. GPS and GIS Methods in an African Rain Forest: Applications to Tropical Ecology and Conservation

    Directory of Open Access Journals (Sweden)

    Nathaniel J. Dominy

    2002-01-01

    Full Text Available Since the completion of the Navstar Global Positioning System (GPS in 1995, the integration of GPS and Geographical Information Systems (GIS technology has expanded to a great number of ecological and conservation applications. In tropical rain forest ecology, however, the technology has remained relatively neglected, despite its great potential. Notwithstanding cost, this is principally due to (1 the difficulty of quality satellite reception beneath a dense forest canopy, and (2 a degree of spatial error unacceptable to fine-scale vegetation mapping. Here, we report on the technical use of GPS/GIS in the rain forest of Kibale National Park, Uganda, and the methodology necessary to acquire high-accuracy spatial measurements. We conclude that the stringent operating parameters necessary for high accuracy were rarely obtained while standing beneath the rain forest canopy. Raising the GPS antenna to heights of 25-30 m resolved this problem, allowing swift data collection on the spatial dispersion of individual rain forest trees. We discuss the impact of the 1996 Presidential Decision Directive that suspended U.S. military-induced GPS error on 1 May 2000, and comment on the potential applications of GPS/GIS technology to the ecological study and conservation of tropical rain forests.

  14. Low-altitude spaceborne GPS receiver for monitoring the ionosphere-magnetosphere interface region

    Science.gov (United States)

    Chiu, Y. T.; Schulz, M.; Schropp, D. R.; Rinaldi, M. A.

    The ionosphere-magnetosphere interface region (IMIR) is difficult to monitor in situ because processes occurring there have short dynamic time scales and long spatial scales. However, a system of spaceborne Global Positioning System (GPS) receivers with upward-looking antennas onboard LEO (low Earth orbit, altitude LEO and GPS orbit (altitude ~ 3 R_E). Phase and group delays between the two GPS signals transmitted through the IMIR are directly proportional to the total line-of-sight electron content, which is the remotely sensed parameter usually required for modeling. LEO spacecraft motion causes the line-of-sight to sweep through the IMIR so as to reveal information about the plasma-density structure. GPS receivers on TOPEX, the NASA/CNES ocean-monitoring satellite at altitude ~ 1430 km, have precisely this capability to monitor the IMIR. Moreover, the two-frequency VHF cross-ranging signals from GPS satellites can be used in the same manner as L-band signals to ``image'' the IMIR. We demonstrate this capability by applying our special deconvolution algorithm to some appropriate TOPEX/GPS data and thereby produce a dynamic display of density structure in the ionosphere-magnetosphere interface region.

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

    Lifescience Database Archive (English)

    Full Text Available GPS2 + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/GPS2.1.tsv http:...//dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/GPS2.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/GPS...2.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/GPS2..tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/.gml ...

  16. Mapping the Coastline Limits of the Mexican State Sinaloa Using GPS

    Science.gov (United States)

    Vazquez, G. E.

    2007-12-01

    This research work presents the delimitation of the coastline limits of Sinaloa (one of the richest states of northwestern Mexico). In order to achieve this big task, it was required to use GPS (Global Positioning System) together with leveling spirit measurements. Based on the appropriate selection of the cited measurement techniques, the objective was to map the Sinaloa's state coastline to have the cartography of approximate 1600 km of littoral. The GPS measurements were performed and referred with respect to a GPS network located across the state. This GPS network consists of at least one first-order-site at each of the sixteen counties that constitute the state, and three to four second-order-sites of the ten counties of the state surrounded by sea. The leveling spirit measurements were referred to local benchmarks pre-established by the Mexican agency SEMARNAT (SEcretaría Del Medio Ambiente y Recursos NATurales). Within the main specifications of the GPS measurements and equipment, we used geodetic-dual-frequency GPS receivers in kinematic mode for both base stations (first and second order sites of the GPS state network) and rover stations (points forming the state littoral) with 5-sec log-rate interval and 10 deg cut-off angle. The GPS data processing was performed using the commercial software Trimble Geomatics Office (TGO) with Double Differences (DD) in post-processing mode. To this point, the field measurements had been totally covered including the cartography (scale 1:1000) and this includes the specifications and appropriate labeling according to the Mexican norm NOM-146-SEMARNAT-2005.

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

    Directory of Open Access Journals (Sweden)

    K. Boniface

    2009-07-01

    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.

  18. Trend-Residual Dual Modeling for Detection of Outliers in Low-Cost GPS Trajectories.

    Science.gov (United States)

    Chen, Xiaojian; Cui, Tingting; Fu, Jianhong; Peng, Jianwei; Shan, Jie

    2016-12-01

    Low-cost GPS (receiver) has become a ubiquitous and integral part of our daily life. Despite noticeable advantages such as being cheap, small, light, and easy to use, its limited positioning accuracy devalues and hampers its wide applications for reliable mapping and analysis. Two conventional techniques to remove outliers in a GPS trajectory are thresholding and Kalman-based methods, which are difficult in selecting appropriate thresholds and modeling the trajectories. Moreover, they are insensitive to medium and small outliers, especially for low-sample-rate trajectories. This paper proposes a model-based GPS trajectory cleaner. Rather than examining speed and acceleration or assuming a pre-determined trajectory model, we first use cubic smooth spline to adaptively model the trend of the trajectory. The residuals, i.e., the differences between the trend and GPS measurements, are then further modeled by time series method. Outliers are detected by scoring the residuals at every GPS trajectory point. Comparing to the conventional procedures, the trend-residual dual modeling approach has the following features: (a) it is able to model trajectories and detect outliers adaptively; (b) only one critical value for outlier scores needs to be set; (c) it is able to robustly detect unapparent outliers; and (d) it is effective in cleaning outliers for GPS trajectories with low sample rates. Tests are carried out on three real-world GPS trajectories datasets. The evaluation demonstrates an average of 9.27 times better performance in outlier detection for GPS trajectories than thresholding and Kalman-based techniques.

  19. Precipitable water trends and variability investigated from homogenized global, long-term, GPS and DORIS datasets

    Science.gov (United States)

    Bock, Olivier; Willis, Pacal; Collilieux, Xavier

    2014-05-01

    High-quality, consistent, global, long-term datasets of zenith tropospheric delay (ZTD) and precipitable water (PW) were produced from Global Positioning System (GPS) and Doppler Orbitography Radiopositioning Integrated by Satellite (DORIS) measurements. The GPS dataset (based on IGS repro1 & trop-new) comprises more than 400 sites over the globe among which 120 sites have more than 15 years of data (1995-2010). The DORIS data comprises 81 sites over the globe with 23 sites having more than 15 years of data. The ZTD data were screened using a two-level screening method. The first level uses post-processing information and applies range checks and outlier checks to ZTD and formal error estimates. It rejects less than 3% of the data. The second screening level detects outliers by comparing GPS and DORIS ZTD data with ECMWF reanalysis (ERA-Interim) data and rejects about 1% of the data. There is good consistency between the screened DORIS and GPS data and the ERA-Interim reanalysis data. However, biases and shifts are evidenced in the DORIS and GPS data which potentially result from instrument changes (e.g. replacement of DORIS Alcatel antennas with Starec antennas). Afterward, the GPS and DORIS PW data were homogenized by applying constant offset corrections based on the median difference with respect to ERA-Interim PW data. Such an offset is applied each time a known station equipment change occurs (based on station log files). Precipitable water vapour trends and variability (seasonal cycle, intra-seasonal and inter-annual variability) from GPS, DORIS and ERA-Interim data are compared at common sites with more than 10 or 15 years of data. Good consistency is found between all three datasets. This work demonstrates the high potential of the GPS and DORIS PW datasets for climate monitoring. These datasets may also be used for the verification of climate model simulations and climate data, e.g. PW measurements from radiosondes and satellites.

  20. Estimation of the GPS to Galileo Time Offset and its validation on a mass market receiver

    OpenAIRE

    GIOIA CIRO; FORTUNY GUASCH Joaquim; PISONI Fabio

    2014-01-01

    The European GNSS, Galileo is currently in its In-Orbit Validation (IOV) phase where four satellites are available for computing the user position. Galileo E1 OS and GPS C/A represent a very effective constellation pair in a consumer grade receiver: the signals are conveyed on the same analog path and measurements can be combined in a single position, velocity and time (PVT) solution, provided that the Galileo to GPS Time Offset (GGTO) is available. Algorithms for GGTO estimation are presente...

  1. Verification of Positional Accuracy of ZVS3003 Geodetic Control ...

    African Journals Online (AJOL)

    The International GPS Service (IGS) has provided GPS orbit products to the scientific community with increased precision and timeliness. Many users interested in geodetic positioning have adopted the IGS precise orbits to achieve centimeter level accuracy and ensure long-term reference frame stability. Positioning with ...

  2. GPS-Aided Gyroscope-Free Inertial Navigation Systems

    OpenAIRE

    Park, Sungsu; Tan, Chin-Woo

    2002-01-01

    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-...

  3. Navigation GPS/GLONASS in the Arctic and aurora

    Directory of Open Access Journals (Sweden)

    Chernouss S. A.

    2016-12-01

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

  4. Network management tools for a GPS datalink network

    Science.gov (United States)

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

    1991-01-01

    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.

  5. Validation of Atmospheric Water Vapor Derived from Ship-Borne GPS Measurements in the Chinese Bohai Sea

    Directory of Open Access Journals (Sweden)

    Shi-Jie Fan

    2016-04-01

    Full Text Available Atmospheric water vapor (AWV was investigated for the first time in the Chinese Bohai Sea using a Global Positioning System (GPS receiver aboard a lightweight (300-ton ship. An experiment was conducted to retrieve the AWV using the state-of-the-art GPS precise point positioning (PPP technique. The effects of atmospheric weighted mean temperature model and zenith wet delay constraint on GPS AWV estimates were discussed in the PPP estimation system. The GPS-derived precipitable water vapor (PWV and slant-path water vapor (SWV were assessed by comparing with those derived from the Fifth Generation NCAR/Penn State Mesoscale Model (MM5. The results showed the PWV and SWV differences between those derived from both GPS and MM5 are 1.5 mm root mean square (RMS with a bias of 0.2 and 3.9 mm RMS with a bias of -0.7 mm respectively. These good agreements indicate that the GPS-derived AWV in dynamic environments has a comparable accuracy with that of the MM5 model. This suggests that high accuracy and high spatio-temporal resolution humidity fields can be obtained using GPS in the Chinese Bohai Sea, which offers significant potential for meteorological applications and climate studies in this region.

  6. Novel Hybrid of LS-SVM and Kalman Filter for GPS/INS Integration

    Science.gov (United States)

    Xu, Zhenkai; Li, Yong; Rizos, Chris; Xu, Xiaosu

    Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) technologies can overcome the drawbacks of the individual systems. One of the advantages is that the integrated solution can provide continuous navigation capability even during GPS outages. However, bridging the GPS outages is still a challenge when Micro-Electro-Mechanical System (MEMS) inertial sensors are used. Methods being currently explored by the research community include applying vehicle motion constraints, optimal smoother, and artificial intelligence (AI) techniques. In the research area of AI, the neural network (NN) approach has been extensively utilised up to the present. In an NN-based integrated system, a Kalman filter (KF) estimates position, velocity and attitude errors, as well as the inertial sensor errors, to output navigation solutions while GPS signals are available. At the same time, an NN is trained to map the vehicle dynamics with corresponding KF states, and to correct INS measurements when GPS measurements are unavailable. To achieve good performance it is critical to select suitable quality and an optimal number of samples for the NN. This is sometimes too rigorous a requirement which limits real world application of NN-based methods.The support vector machine (SVM) approach is based on the structural risk minimisation principle, instead of the minimised empirical error principle that is commonly implemented in an NN. The SVM can avoid local minimisation and over-fitting problems in an NN, and therefore potentially can achieve a higher level of global performance. This paper focuses on the least squares support vector machine (LS-SVM), which can solve highly nonlinear and noisy black-box modelling problems. This paper explores the application of the LS-SVM to aid the GPS/INS integrated system, especially during GPS outages. The paper describes the principles of the LS-SVM and of the KF hybrid method, and introduces the LS-SVM regression algorithm. Field

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

    Science.gov (United States)

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

    2015-01-01

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

  8. Use of GPS TEC Maps for Calibrating Single Band VLBI Sessions

    Science.gov (United States)

    Gordon, David

    2010-01-01

    GPS TEC ionosphere maps were first applied to a series of K and Q band VLBA astrometry sessions to try to eliminate a declination bias in estimated source positions. Their usage has been expanded to calibrate X-band only VLBI observations as well. At K-band, approx.60% of the declination bias appears to be removed with the application of GPS ionosphere calibrations. At X-band however, it appears that up to 90% or more of the declination bias is removed, with a corresponding increase in RA and declination uncertainties of approx.0.5 mas. GPS ionosphere calibrations may be very useful for improving the estimated positions of the X-only and S-only sources in the VCS and RDV sessions.

  9. Placebo use in the UK: a qualitative study exploring GPs' views on placebo effects in clinical practice.

    Science.gov (United States)

    Bishop, Felicity L; Howick, Jeremy; Heneghan, Carl; Stevens, Sarah; Hobbs, F D Richard; Lewith, George

    2014-06-01

    Surveys show GPs use placebos in clinical practice and reported prevalence rates vary widely. To explore GPs' perspectives on clinical uses of placebos. A web-based survey of 783 UK GPs' use of placebos in clinical practice. Qualitative descriptive analysis of written responses ('comments') to three open-ended questions. Comments were classified into three categories: (i) defining placebos and their effects in general practice; (ii) ethical, societal and regulatory issues faced by doctors and (iii) reasons why a doctor might use placebos and placebo effects in clinical practice. GPs typically defined placebos as lacking something, be that adverse or beneficial effects, known mechanism of action and/or scientific evidence. Some GPs defined placebos positively as having potential to benefit patients, primarily through psychological mechanisms. GPs described a broad array of possible harms and benefits of placebo prescribing, reflecting fundamental bioethical principles, at the level of the individual, the doctor-patient relationship, the National Health Service and society. While some GPs were adamant that there was no place for placebos in clinical practice, others focused on the clinically beneficial effects of placebos in primary care. This study has elucidated specific costs, benefits and ethical barriers to placebo use as perceived by a large sample of UK GPs. Stand-alone qualitative work would provide a more in-depth understanding of GPs' views. Continuing education and professional guidance could help GPs update and contextualize their understanding of placebos and their clinical effects. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Nonlinear Filtering with IMM Algorithm for Ultra-Tight GPS/INS Integration

    Directory of Open Access Journals (Sweden)

    Dah-Jing Jwo

    2013-05-01

    Full Text Available Abstract This paper conducts a performance evaluation for the ultra-tight integration of a Global positioning system (GPS and an inertial navigation system (INS, using nonlinear filtering approaches with an interacting multiple model (IMM algorithm. An ultra-tight GPS/INS architecture involves the integration of in-phase and quadrature components from the correlator of a GPS receiver with INS data. An unscented Kalman filter (UKF, which employs a set of sigma points by deterministic sampling, avoids the error caused by linearization as in an extended Kalman filter (EKF. Based on the filter structural adaptation for describing various dynamic behaviours, the IMM nonlinear filtering provides an alternative for designing the adaptive filter in the ultra-tight GPS/INS integration. The use of IMM enables tuning of an appropriate value for the process of noise covariance so as to maintain good estimation accuracy and tracking capability. Two examples are provided to illustrate the effectiveness of the design and demonstrate the effective improvement in navigation estimation accuracy. A performance comparison among various filtering methods for ultra-tight integration of GPS and INS is also presented. The IMM based nonlinear filtering approach demonstrates the effectiveness of the algorithm for improved positioning performance.

  11. The Performance Analysis of Stereo Visual Odometry Assisted Low-Cost INS/GPS Integration System

    Directory of Open Access Journals (Sweden)

    Li-Hung Chen

    2015-08-01

    Full Text Available Visual Odometry (VO is a new method using sequence images acquired from the vehicle which is in motion to estimate the movement. In this research, a novel method is proposed for assisting low-cost INS/GPS integration system with VO system. When GPS signal vanishes, VO can be applied as the backup for GPS to reduce the INS accumulation errors. In order to evaluate the proposed system, the tactical INS/GNSS trajectory is used as the reference trajectory. The Distances Traveled (DT by low-cost INS/GPS and VO modes are calculated. In addition, this study also investigates the accuracy variation in both monocular and stereo-vision VO system, respectively. The purpose is to verify the argument presented in related work. According to the preliminary results, the stereo VO performs well and the position errors in three directions are reduced by using the assisted information including VO position and velocity. It verifies that the proposed integrated system is helpful and efficient in the aspect of increasing the accuracy when GPS signal blockages.

  12. Sensitivity requirements of assisted BDS and GPS in specification 3GPP TS 36.171

    Science.gov (United States)

    Jin, Xiaoxi; Chen, Xin; Ying, Rendong; Yang, Genke

    2016-01-01

    With the needs of growing location-based service, a more high-performance satellite positioning technology - assisted global navigation satellite system (A-GNSS assisted-GNSS) becomes a new hotspot in area of navigation and positioning. Now, 3GPP has already provided supports for GPS, Galileo, GLONASS and QZSS, SBAS, so standardization work of introduction BDS into 3GPP organization is very imperative. In this paper, we first analysis the performance of GPS L1 C/A with assistant information, then by taking into account the difference between BDS and GPS, including the unique nature of GEO/NGEO satellites' navigation message data length and format, we design the sensitivity requirements of BDS B1 following A-GPS. The results between A-GPS and A-BDS of typical sensitivity test cases are shown in this paper, which show that the suggested sensitivity requirements satisfy the minimum performance requirements under technical specification of 3GPP TS 36.171.

  13. Mapping of Marine Area Boundary of Central Java Province using Differential GPS Survey Method

    Directory of Open Access Journals (Sweden)

    Nurul Khakhim

    2004-01-01

    Full Text Available The development of GPS (Global Positioning System technology which is measuring position by satellite, has taken a great metodology aspect of position on surface of earth. The standard GPS measurement takes an absolute positioning. To develop the accurate abd precision, it is used the differential method. Differential GPS measurement can be much more accurate than standard GPs measurement, wherever the method uses one receiver as base station/ reference and the other receiver as field station in a same time. That could reduce and eliminate drifts and errors. The aim of research is use the differential method of GPS survey to map the ocean boundary of Central Java Province. Physical data which neede are base line and base point. Base line were taken from obsrvation of longtime Landsat TM image band 5th based o opinion that shore line are clear seems and easy to interpreted at 10.00 am according to Landsat satellite reording time and the lowest tide time as base line. Location of lowest tide were selected at conspicuous place, such as cape, dry shore, etc and measured base on the BPN (Badan Pertahanan Nasional base/ reference point (orde 2 and 3 on the district, with GPS differential metod. Twelve miles distance from base line of ocean bounddary is belong to province and 1/3 of is belong to district. Characteristic of marine landform as cape, bay, estuaria, attended to international rules. Final report of the research were 1 oean boundary map of Center Java Province, 2 the location and base/ reference points (orde 2 and 3 that could be reference as a base point differential method.

  14. A Low-Cost GPS GSM/GPRS Telemetry System: Performance in Stationary Field Tests and Preliminary Data on Wild Otters (Lutra lutra)

    Science.gov (United States)

    Quaglietta, Lorenzo; Martins, Bruno Herlander; de Jongh, Addy; Mira, António; Boitani, Luigi

    2012-01-01

    Background Despite the increasing worldwide use of global positioning system (GPS) telemetry in wildlife research, it has never been tested on any freshwater diving animal or in the peculiar conditions of the riparian habitat, despite this latter being one of the most important habitat types for many animal taxa. Moreover, in most cases, the GPS devices used have been commercial and expensive, limiting their use in low-budget projects. Methodology/Principal Findings We have developed a low-cost, easily constructed GPS GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) and examined its performance in stationary tests, by assessing the influence of different habitat types, including the riparian, as well as water submersion and certain climatic and environmental variables on GPS fix-success rate and accuracy. We then tested the GPS on wild diving animals, applying it, for the first time, to an otter species (Lutra lutra). The rate of locations acquired during the stationary tests reached 63.2%, with an average location error of 8.94 m (SD = 8.55). GPS performance in riparian habitats was principally affected by water submersion and secondarily by GPS inclination and position within the riverbed. Temporal and spatial correlations of location estimates accounted for some variation in the data sets. GPS-tagged otters also provided accurate locations and an even higher GPS fix-success rate (68.2%). Conclusions/Significance Our results suggest that GPS telemetry is reliably applicable to riparian and even diving freshwater animals. They also highlight the need, in GPS wildlife studies, for performing site-specific pilot studies on GPS functioning as well as for taking into account eventual spatial and temporal correlation of location estimates. The limited price, small dimensions, and high performance of the device presented here make it a useful and cost-effective tool for studies on otters and other aquatic or terrestrial medium

  15. A low-cost GPS GSM/GPRS telemetry system: performance in stationary field tests and preliminary data on wild otters (Lutra lutra).

    Science.gov (United States)

    Quaglietta, Lorenzo; Martins, Bruno Herlander; de Jongh, Addy; Mira, António; Boitani, Luigi

    2012-01-01

    Despite the increasing worldwide use of global positioning system (GPS) telemetry in wildlife research, it has never been tested on any freshwater diving animal or in the peculiar conditions of the riparian habitat, despite this latter being one of the most important habitat types for many animal taxa. Moreover, in most cases, the GPS devices used have been commercial and expensive, limiting their use in low-budget projects. We have developed a low-cost, easily constructed GPS GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service) and examined its performance in stationary tests, by assessing the influence of different habitat types, including the riparian, as well as water submersion and certain climatic and environmental variables on GPS fix-success rate and accuracy. We then tested the GPS on wild diving animals, applying it, for the first time, to an otter species (Lutra lutra). The rate of locations acquired during the stationary tests reached 63.2%, with an average location error of 8.94 m (SD = 8.55). GPS performance in riparian habitats was principally affected by water submersion and secondarily by GPS inclination and position within the riverbed. Temporal and spatial correlations of location estimates accounted for some variation in the data sets. GPS-tagged otters also provided accurate locations and an even higher GPS fix-success rate (68.2%). Our results suggest that GPS telemetry is reliably applicable to riparian and even diving freshwater animals. They also highlight the need, in GPS wildlife studies, for performing site-specific pilot studies on GPS functioning as well as for taking into account eventual spatial and temporal correlation of location estimates. The limited price, small dimensions, and high performance of the device presented here make it a useful and cost-effective tool for studies on otters and other aquatic or terrestrial medium-to-large-sized animals.

  16. A low-cost GPS GSM/GPRS telemetry system: performance in stationary field tests and preliminary data on wild otters (Lutra lutra.

    Directory of Open Access Journals (Sweden)

    Lorenzo Quaglietta

    Full Text Available BACKGROUND: Despite the increasing worldwide use of global positioning system (GPS telemetry in wildlife research, it has never been tested on any freshwater diving animal or in the peculiar conditions of the riparian habitat, despite this latter being one of the most important habitat types for many animal taxa. Moreover, in most cases, the GPS devices used have been commercial and expensive, limiting their use in low-budget projects. METHODOLOGY/PRINCIPAL FINDINGS: We have developed a low-cost, easily constructed GPS GSM/GPRS (Global System for Mobile Communications/General Packet Radio Service and examined its performance in stationary tests, by assessing the influence of different habitat types, including the riparian, as well as water submersion and certain climatic and environmental variables on GPS fix-success rate and accuracy. We then tested the GPS on wild diving animals, applying it, for the first time, to an otter species (Lutra lutra. The rate of locations acquired during the stationary tests reached 63.2%, with an average location error of 8.94 m (SD = 8.55. GPS performance in riparian habitats was principally affected by water submersion and secondarily by GPS inclination and position within the riverbed. Temporal and spatial correlations of location estimates accounted for some variation in the data sets. GPS-tagged otters also provided accurate locations and an even higher GPS fix-success rate (68.2%. CONCLUSIONS/SIGNIFICANCE: Our results suggest that GPS telemetry is reliably applicable to riparian and even diving freshwater animals. They also highlight the need, in GPS wildlife studies, for performing site-specific pilot studies on GPS functioning as well as for taking into account eventual spatial and temporal correlation of location estimates. The limited price, small dimensions, and high performance of the device presented here make it a useful and cost-effective tool for studies on otters and other aquatic or

  17. Multiple inflation events at Akutan volcano, Alaska, from GPS observations

    Science.gov (United States)

    Hyeun Ji, Kang; Rim, Hyoung-Rae

    2017-04-01

    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.

  18. Direct constraints on GIA motion in North America using GPS

    Science.gov (United States)

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

    2004-05-01

    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.

  19. GPS Technology for the Development of Business Information Systems

    Directory of Open Access Journals (Sweden)

    Mihaela MURESAN

    2006-01-01

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

  20. PBO Facility Construction: GPS Network Completed

    Science.gov (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.

    2008-12-01

    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.

  1. Discrete filtering techniques applied to sequential GPS range measurements

    Science.gov (United States)

    Vangraas, Frank

    1987-01-01

    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.

  2. A Java-based tool for creating KML files from GPS waypoints

    Science.gov (United States)

    Kinnicutt, P. G.; Rivard, C.; Rimer, S.

    2008-12-01

    Google Earth provides a free tool with powerful capabilities for visualizing geoscience images and data. Commercial software tools exist for doing sophisticated digitizing and spatial modeling , but for the purposes of presentation, visualization and overlaying aerial images with data Google Earth provides much of the functionality. Likewise, with current technologies in GPS (Global Positioning System) systems and with Google Earth Plus, it is possible to upload GPS waypoints, tracks and routes directly into Google Earth for visualization. However, older technology GPS units and even low-cost GPS units found today may lack the necessary communications interface to a computer (e.g. no Bluetooth, no WiFi, no USB, no Serial, etc.) or may have an incompatible interface, such as a Serial port but no USB adapter available. In such cases, any waypoints, tracks and routes saved in the GPS unit or recorded in a field notebook must be manually transferred to a computer for use in a GIS system or other program. This presentation describes a Java-based tool developed by the author which enables users to enter GPS coordinates in a user-friendly manner, then save these coordinates in a Keyhole MarkUp Language (KML) file format, for visualization in Google Earth. This tool either accepts user-interactive input or accepts input from a CSV (Comma Separated Value) file, which can be generated from any spreadsheet program. This tool accepts input in the form of lat/long or UTM (Universal Transverse Mercator) coordinates. This presentation describes this system's applicability through several small case studies. This free and lightweight tool simplifies the task of manually inputting GPS data into Google Earth for people working in the field without an automated mechanism for uploading the data; for instance, the user may not have internet connectivity or may not have the proper hardware or software. Since it is a Java application and not a web- based tool, it can be installed on one

  3. GPS Time Series Analysis of Southern California Associated with the 2010 M7.2 El Mayor/Cucapah Earthquake

    Science.gov (United States)

    Granat, Robert; Donnellan, Andrea

    2011-01-01

    The Magnitude 7.2 El-Mayor/Cucapah earthquake the occurred in Mexico on April 4, 2012 was well instrumented with continuous GPS stations in California. Large Offsets were observed at the GPS stations as a result of deformation from the earthquake providing information about the co-seismic fault slip as well as fault slip from large aftershocks. Information can also be obtained from the position time series at each station.

  4. 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...

  5. Development of a GPS navigator with Matlab

    OpenAIRE

    Badia Sole, Oriol

    2008-01-01

    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...

  6. Tightly coupled low cost 3D RISS/GPS integration using a mixture particle filter for vehicular navigation.

    Science.gov (United States)

    Georgy, Jacques; Noureldin, Aboelmagd

    2011-01-01

    Satellite navigation systems such as the global positioning system (GPS) are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS)-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF). Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF) was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D) reduced inertial sensors system (RISS) with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle's odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s) even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift, which are

  7. Tightly Coupled Low Cost 3D RISS/GPS Integration Using a Mixture Particle Filter for Vehicular Navigation

    Directory of Open Access Journals (Sweden)

    Jacques Georgy

    2011-04-01

    Full Text Available Satellite navigation systems such as the global positioning system (GPS are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF. Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D reduced inertial sensors system (RISS with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle’s odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift

  8. Norwegian GPs' participation in multidisciplinary meetings: A register-based study from 2007

    Directory of Open Access Journals (Sweden)

    Gjesdal Sturla

    2010-11-01

    Full Text Available Abstract Background An increasing number of patients with chronic disorders and a more complex health service demand greater interdisciplinary collaboration in Primary Health Care. The aim of this study was therefore to identify factors related to general practitioners (GPs, their list populations and practice municipalities associated with a high rate of GP participation in multidisciplinary meetings (MDMs. Methods A national cross-sectional register-based study of Norwegian general practice was conducted, including data on all GPs in the Regular GP Scheme in 2007 (N = 3179. GPs were grouped into quartiles based on the annual number of MDMs per patient on their list, and the groups were compared using one-way analysis of variance. Binary logistic regression was used to analyse associations between high rates of participation and characteristics of the GP, their list population and practice municipality. Results On average, GPs attended 30 MDMs per year. The majority of the meetings concerned patients in the age groups 20-59 years. Psychological disorders were the motivation for 53% of the meetings. In a multivariate logistic regression model, the following characteristics predicted a high rate of MDM attendance: younger age of the GP, with an OR of 1.6 (95% CI 1.2-2.1 for GPs Conclusions Psychological problems including substance addiction gave grounds for the majority of MDMs. GPs with a high proportion of consultations with such problems also participated more frequently in MDMs. List size was negatively associated with the rate of MDMs, while a more disadvantaged list population was positively associated. Working in smaller organisational units seemed to facilitate cooperation between different professionals. There may be a generation shift towards more frequent participation in interdisciplinary work among younger GPs.

  9. Physical Reflectivity and Polarization Characteristics for Snow and Ice-Covered Surfaces Interacting with GPS Signals

    Directory of Open Access Journals (Sweden)

    Shuanggen Jin

    2013-08-01

    Full Text Available The Global Positioning System (GPS reflected signal has been demonstrated to remotely sense the oceans, land surfaces and the cryosphere, including measuring snow depth, soil moisture, vegetation growth and wind direction. Since the Earth surface’s characteristics are very complex, the surface reflectivity process and interaction with GPS signals is not well understood. In this study, we investigate the surface’s reflectivity and variability of snow and ice surfaces interacting with GPS L1 and L2 signals in order to retrieve multipath signals and infer surface characteristics by using the direct and reflected polarizations of each signal. Firstly, the effects of both GPS satellite elevation angle and GPS receiver’s antenna height variations on the multipath signal variability have been investigated by numerical formulations. Secondly, the specular reflection coefficients’ features and the total surface polarization for liquid and solid surfaces are discussed. Moreover, the linear polarization and circular polarizations (co-polarized and cross-polarized as well as their corresponding convolution functions are developed horizontally and vertically. The results show that the multipath signals are more sensitive to the satellite elevation angle variations than to changes in the GPS receiver’s antenna height. The convolution function demonstrates that the snowy surface has a minimum reflectance in circular polarization but maximum reflectance in linear polarization. GPS signals reflecting from an ice-covered surface show a maximum value in circular polarization reflectance and a minimum for linear polarization reflectance. Moreover, the values for reflection from soils are between those for snow and ice in all polarization types. The placement of soil surface reflectance values between snowy and icy surface ones may be noteworthy in new remote sensing applications.

  10. Applying the Water Vapor Radiometer to Verify the Precipitable Water Vapor Measured by GPS

    Directory of Open Access Journals (Sweden)

    Ta-Kang Yeh

    2014-01-01

    Full Text Available Taiwan is located at the land-sea interface in a subtropical region. Because the climate is warm and moist year round, there is a large and highly variable amount of water vapor in the atmosphere. In this study, we calculated the Zenith Wet Delay (ZWD of the troposphere using the ground-based Global Positioning System (GPS. The ZWD measured by two Water Vapor Radiometers (WVRs was then used to verify the ZWD that had been calculated using GPS. We also analyzed the correlation between the ZWD and the precipitation data of these two types of station. Moreover, we used the observational data from 14 GPS and rainfall stations to evaluate three cases. The offset between the GPS-ZWD and the WVR-ZWD ranged from 1.31 to 2.57 cm. The correlation coefficient ranged from 0.89 to 0.93. The results calculated from GPS and those measured using the WVR were very similar. Moreover, when there was no rain, light rain, moderate rain, or heavy rain, the flatland station ZWD was 0.31, 0.36, 0.38, or 0.40 m, respectively. The mountain station ZWD exhibited the same trend. Therefore, these results have demonstrated that the potential and strength of precipitation in a region can be estimated according to its ZWD values. Now that the precision of GPS-ZWD has been confirmed, this method can eventually be expanded to the more than 400 GPS stations in Taiwan and its surrounding islands. The near real-time ZWD data with improved spatial and temporal resolution can be provided to the city and countryside weather-forecasting system that is currently under development. Such an exchange would fundamentally improve the resources used to generate weather forecasts.

  11. Does the modified Glasgow Prognostic Score (mGPS) have a prognostic role in esophageal cancer?

    Science.gov (United States)

    Walsh, Siun M; Casey, Sarah; Kennedy, Raymond; Ravi, Narayanasamy; Reynolds, John V

    2016-06-01

    The modified Glasgow Prognostic Score (mGPS), which combines indices of decreased plasma albumin and elevated CRP, has reported independent prognostic significance in colorectal cancer, but its value in upper gastrointestinal cancer is unclear. The aim of this study was to assess the prognostic significance of mGPS in patients with operable esophageal malignancy. Patients undergoing resection with curative intent between January 2008 and June 2013 were included. The mGPS was scored as 0, 1, or 2 based on CRP(>10 mg/L) and albumin(<35g/L). The mGPS score (0 vs. 1/2 combined) was correlated with patient and tumor characteristics, and operative and oncologic outcomes. Two hundred and twenty-three patients were included. Median (range) follow-up was 21(12-70) months. The mGPS was 0 in 174 patients(78%). mGPS was significantly associated with positive nodal status(P = 0.008) and stage ≥III (P = 0.017). There was a significant improvement in overall survival in patients with mGPS = 0 (47.8 vs. 37.5 months, P = 0.014) but in multivariate analysis, only TNM-stage and nodal status were found to be independent prognostic indicators. mGPS is associated with advanced stage but has no independent prognostic significance and does not impact on operative outcomes. Consequently, this data does not support its routine application in patient selection or prognostication. J. Surg. Oncol. 2016;113:732-737. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Determination of the Ocean Tide Constituents Loading Based on GPS Measurements in the Chinese Offshore Islands

    Science.gov (United States)

    Liu, Y.; Wu, Z.; He, X.; Peng, L.

    2015-12-01

    Ocean tide loading largely affects the accuracy of GPS positioning. In turn, GPS measurements could be used to monitor the ocean tide loading effect. In this paper, 67-days GPS observations from two island GPS stations, respectively located in the East China Sea and the South China Sea, were collected and calculated in 30s sampling rate using the Precise Point Positioning (PPP) algorithm. The variation of GPS observed position time series are 2cm in the horizontal and 7cm in the vertical generated by the ocean tide loading effect and other error sources. With the power spectra analysis by the Fast Fourier Transform (FFT), the eigenvalues of the semidiurnal constituents and the diurnal constituents are obtained from the GPS estimates time series. The calculated frequencies are well agreements to the known within the error less than 1.5% for K1,Q1, O1, K2,S2, M2,N2, but P1 within 4.2%. The calculated amplitudes are also well consistent with the results from the global tide models FES2004,NAO.99 and GOT4.7. Their difference in the amplitude are mostly less than 5mm in the horizontal and the vertical direction, except K1 and M2. The maximum amplitude difference occurs in K1 and M2 up to 1.5cm in the vertical direction. In additional, two islands locate at the different transmission Channel, but they give the same calculated frequency in the horizontal and the vertical directional, respectively for 8 tidal constituents. This exhibits they belongs to the same tide wave system as in fact.

  13. Experience of contractual change in UK general practice: a qualitative study of salaried GPs

    Science.gov (United States)

    Cheraghi-Sohi, Sudeh; McDonald, Ruth; Harrison, Stephen; Sanders, Caroline

    2012-01-01

    Background General practice in the UK underwent major change in 2004, with the introduction of new contracts and a significant element of pay for performance. Although salaried GPs form an increasing proportion of the general practice workforce, little is known of their experiences. Aim To explore the views and experiences of salaried GPs working in English general practice. Design and setting Qualitative study using semi-structured interviews in 17 practices across England, between July 2007 and September 2009. Method Interviews were conducted with 23 salaried GPs. A topic guide included questions on motivations for a career in general practice, descriptions of their daily working environment and duties, practice relationships, and future aspirations. Results The new ability to opt out of out-of-hours responsibilities was deemed positive for the profession but not a major driver for choosing medical speciality. Views regarding the impact of the Quality and Outcomes Framework were ambivalent. Differences in pay were regarded as largely reflective of differences in responsibility between salaried GPs and principals. Most participants reported conducting varied work in collaborative practices. Participants held varying career aspirations. Conclusion Salaried GPs' working experiences were dependent upon personal aspirations and local context. Most salaried GPs were reportedly content with their current position but many also had aspirations of eventually attaining GP principal status. The current lack of available partnerships threatens to undo recent positive workforce progress and may lead to deep dissatisfaction within the profession and a future workforce crisis. Further large-scale quantitative work is required to assess the satisfaction and future expectations of those in salaried posts. PMID:22520916

  14. Study of Alternative GPS Network Meteorological Sensors in Taiwan: Case Studies of the Plum Rains and Typhoon Sinlaku

    Science.gov (United States)

    Chiang, Kai-Wei; Peng, Wei-Chih; Yeh, Yen-Hua; Chen, Kwo-Hwa

    2009-01-01

    Plum rains and typhoons are important weather systems in the Taiwan region. They can cause huge economic losses, but they are also considered as important water resources as they strike Taiwan annually and fill the reservoirs around the island. There are many meteorological sensors available for investigating the characteristics of weather and climate systems. Recently, the use of GPS as an alternative meteorological sensor has become popular due to the catastrophic impact of global climate change. GPS provides meteorological parameters mainly from the atmosphere. Precise Point Positioning (PPP) is a proven algorithm that has attracted attention in GPS related studies. This study uses GPS measurements collected at more than fifty reference stations of the e-GPS network in Taiwan. The first data set was collected from June 1st 2008 to June 7th 2008, which corresponds to the middle of the plum rain season in Taiwan. The second data set was collected from September 11th to September 17th 2008 during the landfall of typhoon Sinlaku. The data processing strategy is to process the measurements collected at the reference stations of the e-GPS network using the PPP technique to estimate the zenith tropospheric delay (ZTD) values of the sites; thus, the correlations between the ZTD values and the variation of rainfall during the plum rains and typhoon are analyzed. In addition, several characteristics of the meteorological events are identified using spatial and temporal analyses of the ZTD values estimated with the GPS network PPP technique. PMID:22408565

  15. The atmosphere- and hydrosphere-correlated signals in GPS observations

    Science.gov (United States)

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

    2015-04-01

    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

  16. Airborne Videography and GPS for Assessment of Forest Damage in Southern Louisiana from Hurricane Andrew

    Science.gov (United States)

    D.M. Jacobs; Susan Eggen-McIntosh

    1993-01-01

    Abstract: One week after Hurricane Andrew made landfall in Louisiana in August 1992, an airborne videography system, with a global positioning system (GPS) receiver, was used to assess timberland damage across a 1.7 million-ha (4.2 million-acre) study area. Ground observations were made to identify different intensities of timber damage and then...

  17. What is an Appropriate Temporal Sampling Rate to Record Floating Car Data with a GPS?

    NARCIS (Netherlands)

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

    2016-01-01

    Floating car data (FCD) recorded with the Global Positioning System (GPS) are an important data source for traffic research. However, FCD are subject to error, which can relate either to the accuracy of the recordings (measurement error) or to the temporal rate at which the data are sampled

  18. Evaluation of RTK-GPS and Total Station for applications in land ...

    Indian Academy of Sciences (India)

    Accuracies of Real-Time Kinematic Global Positioning (RTK-GPS) system and Total Station (TS) were investigated in GIS environment. In geostatistical evaluations, Kriging method was used with spherical, exponential, and Gaussian models. The survey results demonstrated that an area of 3.5 ha or smaller can be best ...

  19. Auxiliary VHF transmitter to aid recovery of solar Argos/GPS PTTs

    Science.gov (United States)

    Christopher P. Hansen; Mark A. Rumble; R. Scott Gamo; Joshua J. Millspaugh

    2014-01-01

    While conducting greater sage-grouse (Centrocercus urophasianus) research, we found that solar-powered global positioning systems platform transmitter terminals (GPS PTTs) can be lost if the solar panel does not receive adequate sunlight. Thus, we developed 5-g (mortality sensor included; Prototype A) and 9.8-g (no mortality sensor; Prototype B) auxiliary very high...

  20. The use of GPS to validate NWP systems : the HIRLAM model

    NARCIS (Netherlands)

    Cucurull, L.; Navascues, B.; Ruffini, G.; Elosegui, P.; Rius, A.; Vilu-Guerau, de J.

    2000-01-01

    A meteorological synoptic situation using Global Positioning System (GPS) observations and a numerical weather prediction (NWP) model in the vicinity of the Madrid Sierra, Spain, between 2 and 15 December 1996 has been studied. The experiment was characterized by high precipitable water (PW) values