# About the accuracy of calculation the main characteristics Earth's gravity field

2014;
: pp. 30-38

Authors:
1
Lviv Polytechnic National University
2
Lviv Polytechnic National University

Objective. The main purpose is to research the requirements for calculation accuracy characteristics of the Earth's gravitational field (quasigeoid heights and plumb line deflection components) based on an analysis of existing methods and requirements to determine these characteristics. Methodology. Gravimetric method is the primary method for determining the height quasigeoid and plumb line deflection components for land and shelf areas. Initial data in this case are results of the gravimetric survey. The main methods of determining the characteristics of Earth's gravitational field is integral transform methods, parametric approximation methods, statistical collocation methods and combined methods. These methods calculate heights of quasigeoid and plumb line deflection components produce with different results on the accuracy of calculations. Methods of integral transforms based on formulas Stokes and Vening-Meynes amended by Molodensky. When using analytic continuation precision calculation of plumb line deflection components this method reaches 0.5-1" for all regions. Parametric approximation methods make it possible to calculate the characteristics of Earth's gravitational field in the central and close areas(V.I. Aronov method) or incorporation of global and regional characteristics (spherical harmonics method). Statistical collocation method uses statistical relationships between the calculated characteristics of the gravitational field and the initial gravity anomalies, but its accuracy is limited due to the replacement of the true values of kovariations on the model values. In the combined method take into account the impact close areas by gravimetric data using the generalized Stokes integral, the impact of distant zones - using geopotential harmonic coefficients. Results. For practical implementation heights quasigeoid and plumb line deflection components definition geosphere surface is divided into a central area (radius 100 km), close (to 1000 km) and long (the rest of the geosphere) zone. It is necessary to have the presence of input information in the form of gravimetric mesurements scale of 1:50 000 for the central zone and the scales of 1:100 000-1:200 000 for close zones. The input information for long areas are modern digital models of the gravity field of the Earth in the form of harmonic geopotential coefficients.  Practical significance. Сalculation of plumb line deflection components should be considered the predominant influence of the central and close areas, quasigeoid heights definition requires a careful consideration of the impact of long areas. For successful application of computation methods of gravity field characteristics must use appropriate gravimetric and topographic information. Originality. Under current requirements, calculations of quasigeoid heights should be accurate to 0.1 m, and the plumb line deflection components - 0.05-0.1". The most efficient and accurate calculating method of these characteristics is combined method.

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