Field comparison of the total station-based QDaedalus and the zenith telescope-based CODIAC astrogeodetic systems for measurements of the deflection of the vertical

The precision and accuracy of a Leica MultiStation 60-based QDaedalus astrogeodetic measurement system are determined through observations at two locations in Switzerland. The precision of the QDaedalus was determined as 0.1 '' for the N-S and E-W deflections of the verticals (DoVs) through 118 series of observations collected over 13 nights (in a 44-day observation period) at the HEIG-VD test station. The accuracy of the QDaedalus system was established by simultaneous parallel observations over two nights using the CODIAC system at the Zimmerwald Observatory. The differences between them were found to be 0.09 '' and 0.02 '' for the N-S and E-W DoV components, respectively. From these results, the accuracies of both DoV components can be interpreted as 0.1 ''. We also found a large systematic trend in the observed N-S DoV data at the HEIG-VD test station (0.008 ''/day). This study is the most extensive thus far for determining the precision and accuracy of the QDaedalus system for astrogeodetic measurements; it is also the first time that QDaedalus system's accuracy has been established using parallel observations.