Digital Zenith Cameras Results and Its Use in DFHRS v.4.3 Software for Quasi-Geoid Determination

The design of digital zenith camera was started in 2010 by Institute of Geodesy and Geoinformatics. Since then the prototype of digital zenith camera has been developed. Now, after improvements of design and manufacturing of the second version, it has reached operational status. This paper describes the construction of zenith camera and features of its control software. The results of vertical deflections' measurements are discussed. At the moment measurements are done in Riga region and are used in DFHRS v.4.3 software in order to check and improve local quasigeoid model. It is a new method of quasigeoid model determination and has not been used in Latvia before. DFHRS (Digital Finite Element Height reference surface (HRS)) software has been developed by Karlsruhe University, Institute of Applied Research (IAF). It is based on parametric modeling of the HRS as a continuous polynomial surface, which in the result allow direct conversion of GNSS-heights h into physical normal heights H.