The Use of Statistical Assumptions at Determining the Support Network Points

Abstract

In many cases, the support network coordinate values determined at different era vary in the limit of measurement and calculation errors. In this case, the question arose is which of the support network points are fixed and which are displaced. The purpose of this paper is to establish the fixed points in the case of repeated measurements in a support network. Based on repeated observations made in the support networks related to hydroenergetical objectives, statistical assumptions were used to determine the displacement points from one era to another and the normality of their distribution. Instrumental observations in the support network were made with high precision total stations. Based on statistical verifications performed in the support network related to Dragan Valley dam, from the eleven pillars, three pillars were established as fixed point. The statistics calculated for the other pillars is greater than the statistics extracted from tables, in this sense these pillars could not be regarded as fixed points. Because of the low support network point displacements from one era to another, the determination of the pillars stability can be achieved only by statistical tests. The stability verification of support networks is extremely important because if the azimuthal measurements of the tracking marks placed on the monitored objective station are performed in displaced points, then the tracking marks coordinate values will be inaccurate.