Dušan Kogoj

An alternative approach to control measurements of crane rails

Horizontal and vertical positions of points for the control assessment of crane rails are classically determined separately. The procedure is time consuming and causes non-homogenous accuracy of the horizontal and vertical position of control points. The proposed alternative approach is based on polar measurements using a high accuracy total station instrument and a special platform with two precise surveying prisms fixed on it. Measurements are carried out from a single station thus ensuring a common coordinate system and homogenous accuracy. The position of the characteristic point of a rail is derived from the measured positions of both prisms with known geometry of the platform. The influence of platform non-horizontality is defined, along with its elimination procedure. Accuracy assessment is ensured with redundant measurements. Result of the proposed procedure is a numerical and graphical presentation of characteristic points. The control parameters required in international Eurocode standards are easily determined from them.

Control Measurements of Crane Rails Performed by Terrestrial Laser Scanning

This article presents a method for measuring the geometry of crane rails with terrestrial laser scanning (TLS). Two sets of crane rails were divided into segments, their planes were adjusted, and the characteristic rail lines were defined. We used their profiles to define the positional and altitude deviations of the rails, the span and height difference between the two rails, and we also verified that they complied with the Eurocode 3 standard. We tested the method on crane rails at the hydroelectric power plant in Krško and the thermal power plant in Brestanica. We used two scanning techniques: “pure” TLS (Riegel VZ-400) and “hybrid” TLS (Leica MS50) scanning. This article’s original contribution lies in the detailed presentation of the computations used to define the characteristic lines of the rails without using the numeric procedures from existing software packages. We also analysed the influence of segment length and point density on the rail geometry results, and compared the two laser scanning techniques. We also compared the results obtained by terrestrial laser scanning with the results obtained from the classic polar method, which served as a reference point for its precision.

Geodetic measurement of distances in athletics

Geodetic measurements are indispensable beyond the borders of surveying technical tasks. In this paper, the usefulness of geodesy in the measurement of sport results is described for throwing events, in accordance with the rules accepted by the IAAF. The article focuses on terrestrial measurements and geometric solutions for the determination of the result of an athlete in the javelin, hammer and discus throw and shot putt. Some effects on measurements within the specified precision of the result are studied. We analyse the influence of ground inclination and gravity on the sport result and the influence of the location of the instrument on the precision of the length of throw.

Statistical testing of directions observations independence

Independence of observations is often assumed when adjusting geodetic network. Unlike the distance observations, no dependence of environmental conditions is known for horizontal direction observations. In order to determine the dependence of horizontal direction observations, we established test geodetic network of a station and four observation points. Measurements of the highest possible accuracy were carried out using Leica TS30 total station along with precise prisms GPH1P. Two series of hundred sets of angles were measured, with the first one in bad observation conditions. Using different methods, i.e. variance–covariance matrices, χ2 test and analyses of time series, the independence of measured directions, reduced directions and horizontal angles were tested. The results show that the independence of horizontal direction observations is not obvious and certainly not in poor conditions. In this case, it would be appropriate for geodetic network adjustments to use variance–covariance matrix calculat...

From Reg Elta to Spatial Station: four decades of ZEISS electronic tacheometers (Trimble).

This paper presents a basic overview of the historical development of electronic tachymeters, through solutions developed by the German manufacturer Zeiss. This factory is responsible for the first instrument of its kind in the world, which is described with special attention. Subsequently, the possibilities of different tachymeters are illustrated in chronological order, over their three decades of evolution. Finally, an overview on the current state of development and production of Zeiss tachymeters is given, since the plant became an integral part of Trimbles large concern.

Geodesy in Geotechnics

Geodetic methods are one of the possible means of determining the stability of geotechnical objects. The determination of the displacements of the geotechnical objects is specific due to the size and the expected displacements. The expected size of the displacement determines the necessary precision of the displacement determination, whereas the size of the object determines the method of the geodetic measurement. We choose either the terrestrical or the GNSS methods. There is no relevant legal framework for geotechnical measurements. For this reason, we present the characteristics of the single methods and suggest general recommendations regarding the implementation of the geodetic procedures when monitoring the displacements of the geotechnical objects. The recommendations are intended for geotechnical engineers planning the geotechnical objects and the operators of geodetic measurements and investors. The recommendations the facilitate supervision of the geotechnical projects.