DBPapers
DOI: 10.5593/SGEM2014/B22/S9.001

A NEW PROCEDURE FOR EXACT JOINT ADJUSTMENT OF THE THREE DIMENSIONAL NETWORK IN THE LARGE AREAS

M. Stroner, P. Trasak
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-11-7 / ISSN 1314-2704, June 19-25, 2014, Book 2, Vol. 2, 3-10 pp

ABSTRACT
Geodetic measurements in three dimensions are common, but were historically performed in two separate components – the height and the position. This separation has originated from used methods, the predominant method of height difference determination was levelling, and position was determined by the angle and distance measurement. Also points were stabilized differently. A longer time in the field of engineering geodesy are used procedures for determining of the coordinates and derived variables based on the total station measurement, and therefore on the simultaneous measurement of the horizontal directions, zenith angles and slope distances. The adjustment of the three-dimensional network is then often used and the procedure is well known, but it can be used with some fundamental limitations. Measured values must be reduced from instrument and target height to point with use of the deflection of the vertical. On small areas the network can be adjusted without any reductions, as in Cartesian coordinate system. On larger areas the measured distances must be reduced to sea level and to the reference surface for the positional coordinates’ calculations, but not for the heights calculation. Existing solution calculates separately positional component (X, Y coordinates) and heights (H), although height differences are calculated from measured zenith angles and slope distances and are correlated with X, Y coordinates. A new solution allowing exact joint adjustment of the three dimensional coordinates is proposed in the paper, a procedure can be used on the large or long building sites without any limitations, points of the network can be also in quite different heights and the reduction to reference surface can be also different for each point.

Keywords: adjustment of geodetic networks, measurement reduction, large building site