Methods of periodical errors analysis for relative gravimeters

Abstract

The aim of the article is the confrontation of the methods of periodical errors analysis for the relative gravimeters LaCoste&Romberg G No.1068 (LCR1068) and No.176 (LCR176). Two methods were used, the harmonic analysis (HA) using least-squares method and the spectral analysis (SA) using Fourier transformation (FFT). Imperfections of gearwheels in the measuring mechanical system cause systematic periodical errors in reading. The periodical errors are being determined at the special gravimetric baselines. The analysis is based on the comparison of gravimeter readings in a counter unit (CU), supposedly affected by periodical errors, with the fixed values of the gravity acceleration (based on many measurements of various gravimeters). Both methods were applied to the same data files and the results were compared. The significant equalities for some periods were found in results. The amplitude magnitudes (almost 0.12 $\mu ms^{-2}) can significantly affect the results of the gravity measurements. However, some discrepancies were found in the results of both methods that limiting usableness of these methods.