CCM.G-K2 key comparison

in Metrologia (2015), 52(1A), 07009

In November 2013 an International Key Comparison, CCM.G-K2, was organized in the Underground Laboratory for Geodynamics in Walferdange. The comparison has assembled 25 participants coming from 19 ... [more ▼]

In November 2013 an International Key Comparison, CCM.G-K2, was organized in the Underground Laboratory for Geodynamics in Walferdange. The comparison has assembled 25 participants coming from 19 countries and four different continents. The comparison was divided into two parts: the key comparison that included 10 NMIs or DIs, and the pilot study including all participants. The global result given by the pilot study confirms that all instruments are absolutely coherent to each other. The results obtained for the key comparison confirm a good agreement between the NMI instruments. Main text. To reach the main text of this paper, click on Final Report [http://www.bipm.org/utils/common/pdf/final_reports/M/G-K2/CCM.G-K2.pdf] . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ [http://kcdb.bipm.org/] . The final report has been peer-reviewed and approved for publication by CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA). [less ▲]

The European Comparison of Absolute Gravimeters 2011 (ECAG-2011) in Walferdange, Luxembourg: results and recommendations

in Metrologia (2013), 50(3), 257

We present the results of the third European Comparison of Absolute Gravimeters held in Walferdange, Grand Duchy of Luxembourg, in November 2011. Twenty-two gravimeters from both metrological and non ... [more ▼]

We present the results of the third European Comparison of Absolute Gravimeters held in Walferdange, Grand Duchy of Luxembourg, in November 2011. Twenty-two gravimeters from both metrological and non-metrological institutes are compared. For the first time, corrections for the laser beam diffraction and the self-attraction of the gravimeters are implemented. The gravity observations are also corrected for geophysical gravity changes that occurred during the comparison using the observations of a superconducting gravimeter. We show that these corrections improve the degree of equivalence between the gravimeters. We present the results for two different combinations of data. In the first one, we use only the observations from the metrological institutes. In the second solution, we include all the data from both metrological and non-metrological institutes. Those solutions are then compared with the official result of the comparison published previously and based on the observations of the metrological institutes and the gravity differences at the different sites as measured by non-metrological institutes. Overall, the absolute gravity meters agree with one another with a standard deviation of3.1 µ Gal. Finally, the results of this comparison are linked to previous ones. We conclude with some important recommendations for future comparisons. [less ▲]

Final report on the Seventh International Comparison of Absolute Gravimeters (ICAG 2005)

in Metrologia (2011), 48

Development of a European Combined Geodetic Network (ECGN)

in Journal of Geodynamics (2005), 40(4-5), 450-460

To ensure the long-time stability of the terrestrial reference system with an accuracy of 10‑9 in the global and continental scale, the interactions between different time-dependent influences of the ... [more ▼]

To ensure the long-time stability of the terrestrial reference system with an accuracy of 10‑9 in the global and continental scale, the interactions between different time-dependent influences of the system Earth to the terrestrial reference system and the related observation has to be considered in the evaluation models. It is proposed to establish a kinematic European Combined Geodetic Network (ECGN) and to integrate the spatial and height reference system into the Earth gravity field parameter estimation. This plan is in agreement with the foreseen IAG project of an Integrated Global Geodetic Observation System (IGGOS). In selected European stations ECGN will establish the combination of time series of spatial/geometric GNSS observations, precise levelling and tide gauge records with gravity field related observations (gravity, Earth tides). Observations are complemented with meteorological parameters, surrounding information of the stations, e.g. eccentricities and ground water level. A first call for participation in the project was directed to the implementation of the ECGN stations. These stations include the standard observation techniques GNSS (GPS/GLONASS—permanent), gravity (super conducting gravimeter and/or absolute gravimeter—permanent or repeated), levelling connections to nodal points of the European levelling network (UELN) (repeated) and meteorological parameters (permanent). A basic constituent of the ECGN stations is a local network for controlling the eccentricities at the 1 mm accuracy level in all three spatial components. For the contributing observation techniques, guidelines have been agreed upon to ensure equal observation principles [less ▲]