Analysis of vertical deflection periodic variations

Abstract

Most of the geodetic measurements are related with the direction of gravity or vertical. Angular, height difference measurements are performed in horizontal coordinate system. Geodetic measurement data are reduced to a uniform coordinate system prior to processing, taking into account gravity field nonhomogenity. However, increasing accuracy of geodetic measurements requires to assess deviations of the vertical caused by the celestial body effect. The aim of this study is to analyze periodic changes to the direction of the vertical, due to effect of the celestial body, and to assess the impact of the closest celestial bodies which have greater impact. Celestial body effect in the vertical deflection components in meridian and prime vertical was examined. Zonal and nonzonal wave’s effect and their amplitude was investigated and evaluated. Results of this work can be used in precise angular measurements and height difference determination, and in the determination of the deflection of the vertical using geodetic astronomy techniques to clarify the shape of the geoid. Results also can be used to assess effect of zonal waves of deflection of the vertical.