Calibration of the LaCoste-Romberg 906 by Comparison with the Superconducting Gravimeter C021 in Membach(Belgium).

Three months of simultaneous and collocated observations by a superconducting and a spring gravimeter in Membach are used to calibrate the spring gravity meter. We show that a precision of 0.1% on the amplitude calibration factor can be achieved with two weeks of data. The time variation of this calibration factor over the three months is found to be less than 0.1%. This is the precision required for our specific application of the spring meter, to validate the ocean tides models along the Atlantic coast. The determination of the instrumental phase lag is not satisfactory. A precision of only a few seconds has been achieved. For phase calibration, other methods are more successful.