High precision vertical gravity gradient determination in Croatia

作者：Repanic M^*; Kuhar M; Malovic I

来源：Acta Geodaetica et Geophysica, 2015, 50(2): 151-171.

DOI：10.1007/s40328-015-0102-z

• Vertical gravity gradient
• High precision gravimetry
• Scintrex CG-3M

The paper depicts high precision vertical gravity gradient determination for the purpose of height reduction in order to connect absolute gravity determinations and high precision relative gravity measurements. Measurements were performed with two Scintrex Autograv CG-3M gravity meters at two absolute gravity stations. Measurement procedure was chosen to reduce influence of hysteresis effect and instrumental noise. Investigation on adjustment model best describing the measurements and their stochastic properties has been carried out, as well as investigations on number of measurements and number of readings influence on estimated vertical gravity gradient precision. On the basis of experimental measurements, it was found expedient to incorporate quadratic daily drift into a functional model. Mathematical correlation of subsequent measurements can then be taken into account by stochastic model. However, if daily drift is modelled as a linear function, better results are accomplished if no correlation is taken into account. Furthermore, measurement of the gravity difference between two levels in 7 iterations (4 observations at each level) by two gravity meters was found sufficient for high precision vertical gravity gradient determination. Moreover, measurement in 6 iterations or conducting more than 10 readings in each observation series does not provide significantly different results. Vertical gradients were determined with standard deviations from 3 to 6 nms(-2)/m, which allow conversion between reference heights of absolute and relative gravity measurements with precision better than 0.01 mu ms(-2).

• 出版日期2015-6