Ideal Combination of Deflection Components and Gravity Anomalies for Precise Geoid Computation

Abstract

Recently, a high-precision and economic system for the real-time measurement of astronomical deflections of the vertical has been available (Müller et al., 2005). Based on the use of a modern digital zenith camera a measurement precision in the order of 0.1 – 0.3 arcseconds can be achieved. Using this efficient and precise technique, a huge amount of deflection measurements can be done in mountainous and desert areas, which usually suffer from a lack of gravity field information (especially gravity anomalies). The combination of the deflections of the vertical with existing gravity networks in order to compute a gravimetric geoid needs two steps. First of all gravity anomalies have to be computed from the deflections of the vertical measured. Second of all an integration of the computed gravity anomalies and the available gravity networks has to be done. This paper analyzes the gravity anomalies computed from the deflection components and the resulting gravimetric geoid solution. The case study is performed for an area in the Austrian Alps where two sets of gravity field data (716 deflections of the vertical and 5796 gravity anomalies) are available.