Quality Assessment of the New Gravity Control in Poland: First Estimate

The new gravity control in Poland is based on absolute gravity measurements. It consists of 28 fundamental stations and 168 base stations. Fundamental stations are located in laboratories; they are to be surveyed in 2014 with the FG5-230 gravimeter. Base stations are monumented field stations; they were surveyed in 2012 and 2013 with the A10-020 gravimeter. The part of the new gravity control consisting of base stations is the subject of the quality assessment. Besides absolute gravity measurements the vertical gravity gradient was determined at all 168 base stations. Nearly 350 single absolute gravity measurement setups and vertical gravity gradient determinations performed provide valuable and comprehensive material to evaluate the quality of the established gravity control. Alongside the establishment of the base stations of the gravity control, multiple additional activities were performed to assure and provide a reliable gravity reference level. These activities concerned regular gravity measurements on monthly basis with the A10-020 on the test network at Borowa Gora Geodetic–Geophysical Observatory, calibrations of metrological parameters of the gravimeter and scale factor calibrations of LCR gravimeters, participation with the in the international (ECAG2011, ICAG2013) and regional comparison campaigns of absolute gravimeters. Careful analysis of the data gathered throughout the project resulted in the estimation of the Total Uncertainty budget for the A10-020 gravimeter on each of 168 base stations. It provides a reliable quality assessment of the new gravity control in Poland.