Geophysical research: article

Estimation of the ambient temperature influence on long-term high-precision measurements with the CG-5 Autograv gravimeter
D.V. Abramov1
N.V. Drobyshev1
D.A. Malysheva2
1 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences 2 Vladimir State University named after Alexander and Nikolay Stoletov
Journal: Geophysical research
Tome: 23
Number: 1
Year: 2022
Pages: 20-29
UDK: 550.831.23:550.312
DOI: 10.21455/gr2022.1-2
Full text
Keywords: CG-5 Autograv gravimeter, zero-point drift, temperature relaxation, algorithm for taking into account the ambidient temperature influence
Аnnotation: The influence of ambient temperature changes on the CG-5 Autograv gravimeter data was analyzed to determine the influence of meteorological factors on long-term gravimetric measurements. The CG-5 Autograv gravimeter provides continuous measurement of the body temperature, which is an objective assessment of the ambient temperature. Experimental results of long-term observations at the gravimetric point confirm the need to take into account the change in the drift velocity of the zero point of the gravimeter caused by the change in the ambient temperature that occurs despite the operation of the thermostat. It was found that the change in zero-point drift velocity is somewhat lagged in relation to the change in the temperature of gravimeter body. The magnitude of the inertial lag is essentially the duration of the temperature relaxation of the device, which develops depending on specific temperature dynamics. The inertial nature of the measuring system reaction of thermostated gravimeter to the change in the body temperature was described by the mathematical model of temperature relaxation. As such a model, it is proposed to consider the temperature that most accurately correlates with the drift velocity (“effective” temperature), represented as a set of first-order aperiodic links. In order to determine the parameters of the aperiodic links, reference gravimetric measurements were performed with simultaneous measurement of the gravimeter body temperature under various conditions of changing ambient temperature. The values of the parameters of aperiodic links were determined by the maximum correlation between the drift velocity of the gravimeter zero-point and the “ef-fective” temperature. After determining the coefficient of dependence of gravimeter drift velocity nonlinear component on the “effective” temperature, it became possible to build a model for compensating the gravimeter drift nonlinear component. As a result, the model of the nonlinear drift component compensation by the value of the “effective” temperature, together with the temperature relaxation model, can be presented as an algorithm for taking into account the influence of the ambient temperature on the nonlinear component of the gravimeter drift velocity.
Bibliography: Abramov D.V., Drobyshev M.N., Koneshov V.N., Estimating the influence of seismic and meteorological factors on the accuracy of measurements by relative gravimeters, Izvestiya, Physics of the Solid Earth, 2013, vol. 49, no. 4, pp. 548-553.

Abramov D.V., Koneshov V.N., Chebrov V.N., Improvements of long time observation technique by relative gravimeter CG-5 methodic, Seismicheskie pribory (Seismic Instruments), 2016, vol. 52, no 3, pp. 20-26. [In Russian].

Drobyshev M.N., Koneshov V.N., Evaluation of the gravimeter CG-5 Autograv limit accuracy, Seismicheskie pribory (Seismic Instruments), 2013, vol. 49, no. 2, pp. 39-43. [In Russian].

Drobyshev M.N., Koneshov V.N., Allowance for seismic impact on high-frequency measurements by the Auto-grav CG-5 gravimeter, Izvestiya. Physics of the Solid Earth, 2014, vol. 50, no. 4, pp. 588-591.

Elsaka B., Comparison of different polynomial degrees for correcting the instrumental drift of Scintrex CG-5 Autograv gravimeter, Austrian journal of basic and applied sciences, 2020, vol. 14, no. 5, pp. 19-25. DOI: 10.22587/ajbas.2020.14.5.3

GOST RV 1.1-96. Gosudarstvennaya sistema standartizatsii Rossiiskoi Federatsii. Metrologicheskoe obespechenie vooruzheniya i voennoi tekhniki. Osnovnye polozheniya (GOST RV 1.1-96. State system of standardization of the Russian Federation. Metrological support of weapons and military equipment. Basic provisions), Moscow: Gosstandart of Russia, 1996. [In Russian].

Hemming R.V., Digital filters, Mishawaka, IN, USA: Better World Books, 1983, 221 p.

Otnositel'nyi gravimetr CG-5. Sistema Scmtrex Autograv: Rukovodstvo po ekspluatatsii. red. 4 (Relative gravi-meter CG-5. Scmtrex Autograv System: Operation Manual. ed. 4), Ontario: Scintrex, 2008, 156 p. [In


Seigel H.O., A guide to high precision land gravimeter surveys, Ontario: Scintrex, 1995, 122 p.

Yu H., Guo J., Li J., Mu D., Kong Q., Zero drift and solid Earth tide extracted from relative gravimetric data with principal component analysis, Geodesy and Geodynamics, 2015, vol. 6, is. 2, pp. 143-150.