A transportable absolute gravity meter adopting the symmetric rise and falling method

The Gravimetry Group of the Institute of Metrology “G. Colonnetti” (IMGC-CNR), nowadays National Institute of Research in Metrology (INRIM), developed a new version of a transportable absolute gravimeter, the IMGC-02. The instrument presents several improvements mainly concerning the transportability, the measurement automation and the user-interface programs. According to the ISO-GUM (Guide to the Expression of Uncertainty in Measurements), an extensive analysis concerning the contributors to the uncertainty budget has been conducted. At present the instrumental expanded uncertainty (p = 95 %) is believed to be about 8 parts in 10-9 of the surface gravity value. The detailed description of the IMGC-02 apparatus and an outline of its metrological characterization is the subject of this paper