Final report of key comparison CCM.G-K1: International comparison of absolute gravimeters ICAG2009

Abstract

The International Comparison of Absolute Gravimeters 2009 (ICAG2009) was carried out in September 2009 at the International Bureau of Weights and Measures (BIPM). The ICAG2009 and its data processing were performed in accordance with the agreed Technical Protocol which was approved by the Steering Committee. The pilot laboratory (BIPM) evaluated the final results of the key comparison from the measurements made at the BIPM in the framework of ICAG2009. A pilot study run in parallel allowed evaluation of the offsets for absolute gravimeters from institutes not fulfilling the requirements for participating in the key comparison. The gravity values at the five stations, and the offsets for each absolute gravimeter, were obtained by a weighted least squares fit. The results indicate that all participating gravimeters are consistent within their expanded uncertainties.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Absolute gravity acceleration measurement in atomic sensor laboratories

“…Such a reference value would allow correction values to be determined for the results of the gravimeters participating in the comparison. Preliminary results [22] show that the FG5#238 absolute gravimeter measured the acceleration of gravity in three different sites with an expanded uncertainty ranging between 5.4 µGal and 6.5 µGal. The expanded uncertainty is obtained by multiplying the combined standard uncertainty by a coverage factor k corresponding to a confidence level of 95%, in our case k = 2.…”

“…The comparison was held from September 14th to October 3th, 2009 in Sèvres, France, and preliminary results are described in [22]. In ICAG-2009, five stations located at the BIPM were used and each gravimeter measured at three of them.…”

Self-attraction mapping and an update on local gravitational acceleration measurement in BIPM Kibble balance

“…Since the ICAG2009 measurement was made 8 years ago, the long-term stability of the g value at the Kibble balance site should be evaluated. Figure 8 shows the historical g measurement differences from 2001 to 2009 based on comparison reference values (CRVs) [31][32][33]. To take the long-term g stability into account, we added an extended uncertainty component of 1.6 µGal, which covers all the measurement results (with uncertainties) of the CRVs.…”

The self-attraction correction for the FG5X absolute gravity meter

“…National and international comparisons of instruments are now routinely organized under the auspices of various governing agencies. Arias et al [5] recently presented the final report of the most recent key comparison CCM.G-K1, also called ICAG2009 (International Comparison of Absolute Gravimeters), held at the BIPM in Sèvres, France. These comparisons typically include a diverse array of instruments, and any unique characteristic that can cause a bias in the measurement must be explicitly accounted for to produce a valid intercomparison.…”