Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Emardson T. Ragne 1969 ) "

Sökning: WFRF:(Emardson T. Ragne 1969 )

  • Resultat 1-10 av 13
Sortera/gruppera träfflistan
  • Emardson, Ragne, et al. (författare)
  • Spatial variability in the ionosphere measured with GNSS networks
  • 2013
  • Ingår i: Radio Science. - 0048-6604. ; 48:5, s. 646-652
  • Tidskriftsartikel (refereegranskat)abstract
    • Travelling Ionospheric Disturbances (TIDs) appear as Medium-Scale TIDs at mid-latitudes and as polar cap patches at high latitudes. Both can have a negative impact on GNSS measurements although the amplitude is of tenths of a TECU. Due to their spatial extension they affect GNSS measurements using receivers separated with distances up to ~1000 km. We present statistical measures of the ionospheric spatial variability as functions of time in solar cycle, annual season, and time of day for different geographical locations in Europe. In order to perform this spatial characterization of the ionosphere, we have used archived GPS data from a thirteen year period, 1999-2011, covering a complete solar cycle. We find that the ionospheric spatial variability is larger for the northern areas than for the southern areas. This is especially pronounced at solar maximum. For the more northern areas, the ionospheric variability is greater during night time than during day time, while for central Europe the variability is larger during day time. At solar maximum, the variability is larger during the months October and November and smaller in June and July.
  • Steinmetz, Erik, et al. (författare)
  • Assessment of GPS derived speed for verification of speed measuring devices
  • 2014
  • Ingår i: Int. J. of Instrumentation Technology. - 2043-7854. ; 1:3, s. 212-227
  • Tidskriftsartikel (refereegranskat)abstract
    • Speed information from GPS is increasingly used and provides an alternative to conventional methods such as wheel speed sensors. We investigate the possibility to use GPS derived speed as a reference when verifying laser and radar-based speed measuring devices used in traffic enforcement. We have set up a realistic test scenario where a GPS equipped vehicle was driven at three different speeds (40, 90 and 130 km/h) through a pre-defined measurement zone. An independent and traceable reference speed was calculated by accurately measuring the length of the measurement zone (approximately 15 metres), and the time it took to pass through it. The reference speed was compared to the average GPS speed for each passage. This comparisons show that the standard uncertainty of such GPS speed measurements is less than 0.05 km/h. Hence, GPS derived speed meets the accuracy requirements for verification of laser and radar based speed measuring devices.
  • Hedekvist, Per Olof, 1967-, et al. (författare)
  • Accurate time transfer utilizing the synchronization in an SDH-network
  • 2006
  • Ingår i: 2006 Optical Fiber Communication Conference, and the 2006 National Fiber Optic Engineers Conference; Anaheim, CA; United States; 5 March 2006 through 10 March 2006. - 978-155752803-2
  • Konferensbidrag (refereegranskat)
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 13
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy