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Open Access

Effect of troposphere slant delays on regional double difference GPS processing

  • Maaria Nordman18Email author,
  • Reima Eresmaa28,
  • Johannes Boehm38,
  • Markku Poutanen18,
  • Hannu Koivula18 and
  • Heikki Järvinen28
Earth, Planets and Space200961:BF03353195

Received: 7 July 2008

Accepted: 11 March 2009

Published: 31 August 2009


The demand for geodetic time series that are accurate and stable is increasing. One factor limiting their accuracy is troposphere refraction, which is hard to model and compute with sufficient resolution, both in time and space. We have studied the effect of numerical weather model (NWM)-derived troposphere slant delays and the most commonly used mapping functions, Niell and Vienna, on Global Positioning System (GPS) processing. Six months of data were calculated for a regional Finnish network, FinnRef, which consists of 13 stations, using Bernese v. 5.0 in double difference mode. The results showed that when site-specific troposphere zenith delays or gradients are not estimated, the use of NWM-based troposphere delays improved the repeatabilities of all three components of station positions (north, east and up) statistically significantly and up to 60%. The more realistic troposphere model also reduces the baseline length dependence of the solution. When site-specific troposphere delays and the horizontal gradients were estimated, there was no statistically significant improvement between the different solutions.

Key words

Troposphere slant delaysgeodetic time seriesGPS processingdouble difference mode