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GPS Metrology: Bringing Traceable Scale to a Local Crustal Deformation GPS Network

  • H. KoivulaEmail author
  • P. Häkli
  • J. Jokela
  • A. Buga
  • R. Putrimas
Conference paper
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 136)

Abstract

A constant scale difference between GPS solutions and traceable electronic distance measurement (EDM) results was found during semi-annually repeated campaigns performed in Olkiluoto, Finland. Since EDM results are very accurate and uncertainties are well-defined, this leads to an assumption that the GPS solution is biased.

At the Kyviškės test field in Lithuania, the true lengths with traceable uncertainties between observation pillars were measured using a Kern ME5000 Mekometer as a scale transfer standard. GPS observations were processed using individual and type calibrated antenna tables, a local and global ionosphere model, and three different cut-off elevation angles, and several linear combinations and were then compared with the EDM results. The results show that the ambiguity resolution strategy and antenna calibration model play a significant role compared to the cut-off elevation angle and ionosphere model.

Individual antenna calibration is required for the best metrological accuracy by means of the best agreement with traceable EDM results. The best metrological agreement was obtained with an L1 solution and individually calibrated antennas. The rms and maximum difference to the true (EDM) values were 0.3 and 0.7 mm, respectively. However, a clear distance dependency of 0.5 ppm was also evident. In particular, linear combinations with type calibrated tables caused variations up to 4 mm from the true value, even when high quality choke ring antennas were used. With individually calibrated antennas, all solutions were within ±1 mm of the true value.

Keywords

Ionosphere Model Scale Transfer Calibration Table Antenna Calibration Electronic Distance Measurement 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This project was partly funded by the Academy of Finland; Decision number 122822. Prof. Martin Vermeer and his group from the Helsinki University of Technology (Laboratory of Geoinformation and Positioning) are acknowledged for letting us to borrow their Mekometer Kern ME5000.

References

  1. Ahola J, Koivula H, Poutanen M and Jokela J (2008) GPS Operations at Olkiluoto, Kivetty and Romuvaara in 2007. Working Report 2008–35. Posiva Oy. p 189Google Scholar
  2. BIPM (2008) Evaluation of measurement data – guide to the expression of uncertainty in measurement (GUM). JCGM 100:2008. Joint Committee for Guides in Metrology. p 120Google Scholar
  3. Buga A, Jokela J and Putrimas R (2008) Traceability, stability and use of the Kyviškės calibration baseline – the first 10 years. In Cygas, D. and K.D. Froehner (eds.): The 7th International Conference Environmental Engineering, Selected Papers, vol 3, p 1274–1280. Vilnius, Lithuania, May 22–23, 2008Google Scholar
  4. Dach R, Hugentobler U, Fridez P, Meindl M (eds) (2007) Bernese GPS Software Version 5.0. Astronomical Institute, University of Bern, SwitzerlandGoogle Scholar
  5. Görres B, Campbell J, Becker M, Siemes M (2006) Absolute calibration of GPS antennas: laboratory results and comparison with field and robot techniques. GPS Solutions 10:136–145CrossRefGoogle Scholar
  6. Jokela J, Petroškevičius P, Tulevičius V (1999) Kyviškės Calibration Baseline. Reports of the FGI, 99:3, p 15Google Scholar
  7. Jokela J, Häkli P, Ahola J, Buga A, Putrimas R (2009) On traceability of long distances. In: Proceedings of XIX IMEKO World Congress, Fundamental and Applied Metrology, September 6–11, 2009, Lisbon, Portugal, pp 1882–1887, IMEKO, ISBN 978-963-88410-0-1Google Scholar
  8. Mader GL (1999) GPS antenna calibration at the National Geodetic Survey. GPS Solutions 3:50–58CrossRefGoogle Scholar
  9. Schmitz M, Wübbena G, Boettcher G (2002) Tests of phase center variations of various GPS antennas, and some results. GPS Solutions 6:18–27CrossRefGoogle Scholar
  10. Wanninger L (2009) Correction of apparent position shifts caused by GNSS antenna changes. GPS Solutions 13:133–139CrossRefGoogle Scholar
  11. Wübbena G, Schmitz M, Menge F, Böder V, Seeber G (2000) Automated absolute field calibration of GPS antennas in real time. Proceedings of ION GPS 2000, 19–22 September, Salt Lake City, Utah, USAGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • H. Koivula
    • 1
    Email author
  • P. Häkli
    • 1
  • J. Jokela
    • 1
  • A. Buga
    • 2
  • R. Putrimas
    • 2
  1. 1.Department of Geodesy and GeodynamicsFinnish Geodetic InstituteMasalaFinland
  2. 2.Vilnius Gediminas Technical University, Institute of GeodesyVilniusLithuania

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