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Real-time determination of VLBI radio telescope reference points to link the IVS and IGS reference frames

Objective

The aim of this research project is to develop efficient methods of measurement for the determination of VLBI reference point parameters by using powerful kinematic measurement systems with the following key points:

  • Achievement of the required sub-millimeter accuracy,
  • Reduction of the telescope’s downtime and
  • Application process for technical surveying personnel with little training.

Status of Work

In order to meet the above objectives, a new mathematical adjustment model was first set up. Using the desired parameters of a VLBI radio telescope, this model could be measured reliably. In this case, the experiences and insights of Dipl.-Ing. Cornelia Eschelbach, who in 2002 had already conducted telescope surveys in Onsala (Sweden), hold valuable conclusions derived from her own work. A partial validation of the evaluation procedure was carried out using simulations and an axis model in the Institute’s laboratory. The formulaic relationships of the evaluation model were presented in the spring of 2008 at Measuring the Changes.

Furthermore, practical methods and devices such as laser trackers or tachymeters were examined using measurement parameters. These parameters were included in the established model, and can be determined reliably with the required precision.

In order to test the evaluation concept created under real conditions, a VLBI reference point determination of a radio telescope is essential. To this end, radio telescope measurements have been carried out at the Fundamental station in Wettzell (Germany) and the Onsala Space Observatory (Sweden).

Digital Impressions from Wettzell (Germany)

Here are a few pictures of the surveying work at the Fundamental station in Wettzell. Click to enlarge an image.

VLBI-Referenzpunktbestimmung am RT Wettzell 2008: Teleskope VLBI-Referenzpunktbestimmung am_RT Wettzell 2008: Lasertracker VLBI-Referenzpunktbestimmung am_RT Wettzell 2008: LTD500Messung VLBI-Referenzpunktbestimmung am RT Wettzell 2008: CCRs VLBI-Referenzpunktbestimmung am RT Wettzell 2008: Hebebühne VLBI-Referenzpunktbestimmung_am_RT_Wettzell_2008_Reflektorenanbringung

More pictures can be found in the gallery at RT Wettzell 2008 entitled VLBI reference point determination.

Digital Impressions from Onsala (Sweden)

The following pictures were taken at the Onsala Space Observatory during survey work. Click to enlarge an image.

IVS-Referenzpunktbestimmung am 20m Teleskop in Onsala 2008: Lasertracker IVS-Referenzpunktbestimmung am 20m Teleskop in Onsala 2008: OSO-Teleskope IVS-Referenzpunktbestimmung am 20m Teleskop in Onsala 2008: Radioteleskop IVS-Referenzpunktbestimmung am 20m Teleskop in Onsala 2008: Radom IVS-Referenzpunktbestimmung am 20m Teleskop in Onsala 2008: Stationierung IVS-Referenzpunktbestimmung am 20m Teleskop in Onsala 2008: Vermessung

More pictures can be found in the IVS-reference point determination gallery from 20m telescope at Onsala 2008.

Literature

  • Neidhardt, N.; Klügel, T.; Lösler, M.; Eschelbach, C.; Schenk, A. (2010): Monitoring the stability of the radio telescope Wettzell. European Geosciences Union (EGU), General Assembly 2010, 02.–07. Mai 2010, Wien, Österreich.

 

  • Neidhardt, A.; Lösler, M.; Eschelbach, C.; Schenk, A. (2010): Permanent monitoring of the reference point at the 20m radio telescope Wettzell. 6th IVS General Meeting, Hobart, TAS, Australia, 7.-13. Februar, 2010. Poster as PDF

 

  • Lösler, M.; Eschelbach, C.; Schenk, A.; Neidhardt, A. (2010): Permanentüberwachung des 20m VLBI-Radioteleskops an der Fundamentalstation in Wettzell. Zeitschrift für Geodäsie, Geoinformatik und Landmanagement (ZfV), Vol. 1/2010, 135, S. 40-48, 2010.

 

  • Lösler, M. (2010): Hochpräzise Bestimmung des Achsenschnittpunktes eines 20m VLBI-Radioteleskopes mit einem (geneigten) Lasertracker. In: Ernst & Sohn (Hrsg.): Sonderheft Messtechnik im Bauwesen 2010, 2010. (article as PDF)

 

  • Lösler, M. (2009): Bestimmung des lokalen Verbindungsvektors zwischen IVS- und IGS-Referenzrahmen am Raumobservatorium Onsala (Schweden). Allgemeine Vermessungs-Nachrichten (AVN), Vol. 11/12, 116, S. 382-387, 2009. (article as PDF)

 

  • Lösler, M. (2009): A New Mathematical Model for Reference Point Determination of an Azimuth-Elevation Type Radio Telescope.  Journal of Surveying Engineering, Band 135, 2009.

 

  • Lösler, M.; Eschelbach, C. (2009): Evolution and obtained expertise in reference point determination at the GIK. Bourda, G./ Charlot, P., Collioud/ A. (Hrsg.): Proceedings of the EVGA - European VLBI for Geodesy and Astrometry, Bordeaux, Frankreich, 23.-24. März 2009. S.116-121. (article as PDF)

 

  • Lösler, M.; Haas, R. (2009): The 2008 Local-tie Survey at the Onsala Space Observatory. Bourda, G., Charlot, P., Collioud, A. (Hrsg.): Proceedings of the EVGA - European VLBI for Geodesy and Astrometry, Bordeaux, Frankreich, 23.-24. März 2009. S.97-101. (article as PDF)

 

  • Lösler, M. (2008): Reference point determination with a new mathematical model at the 20 m VLBI radio telescope in Wettzell.  Journal of Applied Geodesy 2 (2008), S. 233-238. (article as PDF)

 

  • Lösler, M.; Hennes, M. (2008): An innovative mathematical solution for a time-efficient IVS reference point determination. Proceedings of the FIG2008 – Measuring the changes, Portugal, Lisbon 12.-15. May 2008. (article as PDF)

 

Support

This research project is funded by the DFG and maintained under the Fördungsnummer HE5213_2-1.

Contact:

Dr.-Ing. Manfred Juretzko