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Zumberge J. F., Heflin M. B., Jefferson D. C., Watkins M. M., Webb F. H. Precise point positioning for the efficient and robust analysis of GPS data from large networks, J. Geophys Research , Vol. 102, No.B3

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The GPS-derived TEC has proved to be a robust characteristic representing well the state of the Earth's ionosphere-plasmasphere system during both quiet and disturbed geomagnetic conditions. Successfully forecasting the TEC value can prove invaluable when trying to improve the communications, navigation, and surveying practices. Presented is a new forecasting method based on  auto-correlation analysis and consisting of two major parts - first, extrapolation of the TEC monthly medians using Fourier series approximation, and second, geomagnetically-correlated forecast of the TEC relative deviations of from its median value. Preliminary tests show a good agreement between measured and predicted median values. Presented are also important investigations related to the short-term forecast.

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GPS data from a dense network of receivers can be an important source of information on Travelling Ionospheric Disturbances (TIDs), especially for smaller scale fluctuations (small and medium scale TIDs). Since absolute TEC ``calibration'' is not necessary it is sufficient to work with GPS differential phase data. We are using data from a dense network of GPS receivers distributed over Austria to assess TID activities on a bi-hourly basis. The raw data are stored in the well-known RINEX format. The phase differences are extracted and after correction of ``cycle slips'' the data are subjected to band-pass filtering. Cycle slip correction is a tricky but necessary process. The use of ``cycle slip free'' time intervals would leave only a fraction of available data for TID activity assessment. We describe the data retrieval and preparation system and show first results (case studies and preliminary results).

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Nowadays, GPS is the best positioning system with its constellation, but number of GLONASS satellites increased to the required number, with launched new ones, for positioning. With recent revitalization of GLONASS, a great number of high precision GLONASS and GPS/GLONASS receivers have been produced. In this paper, baselines of two networks have been analyzed in order to assess the usability of GLONASS on global positioning. In both networks, repeatabilities of results were investigated by using GPS, GLONASS and GPS/GLONASS data. Results revealed that repeatabilities of all baselines by using GLONASS observations are not consistent when compared to the GPS and GPS/GLONASS.

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While the cadastral and topographic maps tie to the classical reference systems and frames, there will be need to know the relation between the classical and GPS-based networks in a particular country. In this study we discuss the scale factor and azimuth discrepancies between the Hungarian first order triangulation and the national GPS network emphasising their practical significance.The comparison of traditional and GPS derived slope and geodesic distances as well as the comparison of the different azimuths make possible the estimation of the scale and orientation differences of the two systems without the knowledge of height and geoid information which may contain additional errors, too.The estimated −4.34 mm/km mean value reflects the significant scale difference, which is similar to the values derived in neighbour countries. The −2.51 arcsec mean azimuth difference reflects the orientation of the two system.

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Measurements of Total Electron Content (TEC) were obtained from GPS and digisonde data, at Tucumán (26.69°S, 65.23°W), for days in different seasons, and with different geomagnetic activities, in 2004. Differences between both methods — associated with plasmaspheric content — are analyzed regarding hourly behavior, magnetic activity, and season; and are also compared with other latitude data. Results show a general good agreement between both methods, GPS measurements being generally higher around the diurnal maximum; results agree with theoretical predictions and findings from other authors as well.Maximum TECs occur in equinox, particularly, on magnetically perturbed days. Concerning the plasmaspheric content, our results do not show clear differences between quiet and perturbed days. The seasonal behavior can be associated with variations of the equatorial anomaly.

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In the frame of this investigation systematic comparison is performed between the ITEC values (total electron content derived from ionograms) calculated from Athens Digisonde observations and TEC data derived for Athens coordinates from the TEC maps produced by the DLR/IKN for Europe, using GPS measurements. The first results of the comparison study performed between the two data sets shows that apart of the general daytime agreement, a systematic deviation of ITEC towards lower values during nighttime hours is present. Given the adequate accuracy of both independent measurements, the observed difference during nighttime could provide a measure of the plasmaspheric content wich is an open issue in both geomagnetically disturbed and undisturbed periods and further improve existing plasmaspheric models.

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placebos among Hungarian GPs — a preliminary research report Clin. Exp. Med. J. 5 21 – 25 . [22]. N. Lynöe B. Mattsson M. Sandlund 1993 The attitudes of patients and physicians towards placebo treatment — a comparative study Soc

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Physiology International
Authors:
György Szigeti
,
Gábor Schuth
,
Tamás Kovács
,
Péter Revisnyei
,
Alija Pasic
,
Ádám Szilas
,
Tim Gabbett
, and
Gábor Pavlik

(GPS) technology is widely used for recording and analysing match and training load of players [ 2 ]. Despite the general popularity of GPS, it also has its limitations. Closed stadiums, indoor training sessions, sampling frequency, and other external

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. Road safety conditions of municipal roads operation: identification of accident black-spots with GPS coordinates, (in Hungarian) , Thesis on Post Graduate Course about Transport Engineering Technology , Széchenyi István University, 2016

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