Geodesia et Descriptio Terrarum (Geodezja i Kartografia) 7 (4) 2008
APPLICATION OF ROBUST ESTIMATION METHODS TO GEODETIC DESCRIPTION OF BUILDING DEFORMATION
geodetic description of deformations, robust estimation methods
The three-dimensional transformation without change of scale is one of methods for geodetic description of building deformations. Object displacement parameters (rotation angles and components of translation vector) and values of reduced displacement vectors are delivered as a result of fitting two sets of check points (from initial survey and check one). Usually these calculations are done with the help of the least squares method. This method is very sensitive to influence of outliers. Considerable local deformations of object can cause distortion of obtained results. In the paper the possibility of the using for geodetic description of building deformation five robust estimation methods is presented. Results of fit obtained in this way are more reliable. This fact is very important for correct assessment of construction safety. This problem is illustrated by simulated building object.
The main aim of the thesis was the evaluation of actual accuracy of survey results obtained by using suggested technology. In this purpose satellite measurements realized by RTK technique have been repeated many times on several control points of EUREF-POL and POLREF network. Additionally, few different types of corrections offered by Satellite Positioning System of Małopolska were used in measurements. For estimate of the quality of obtained results, statistical tests of goodness of fit distribution of errors, have been applied. The results of numerical analysis of experimental measurements allowed, on present stage, to general state, that obtained real time measurements accuracies are contained in 1–3 cm limit in horizontal position and 1–5 cm limit in vertical, that corresponds to basic guidelines of the created system. Moreover, it has been determined by using this technology we avoid problems with the radio range and disturbances of its signal in comparison with the traditionally realized RTK method.
APPLICATION OF GPS TECHNOLOGY FOR CONTROL POINTS POSITION DETERMINATION USED FOR THE RING ROAD OF WYSZKÓW CITY
Mieczysław Bakuła, Roman Bornus, Rafał Gregorczyk, Wojciech Jarmołowski, Stanisław Oszczak, Renata Pelc-Mieczkowska
GPS, control points, ambiguity solution
The paper presents methods of measurements and post-processing of GPS observations for engineering applications used for construction of highways. The measurements of geodetic control points on the distance of 13 km of the ring road of Wyszkow were done with the use of seven GPS receivers as Ashtech Z-XII, Ashtech Z-Surveyor and Ashtech Z-Xtreme. The control points of network were situated close to wooden area what makes more difficult accurate coordinates determination. In such situation it is extremely important to choose a proper methodology of GPS measurements and post-processing strategy in order to obtain high and reliable accuracy. The methodology of measurement and post-processing of GPS data presented in this paper allowed to obtain 2-3 mm accuracy after network adjustment having 1.5 – 3 hours GPS sessions.
The paper describes cartographical modelling the changeability of phenomena. Author proposed the classification of the methods of representing the changeability of phenomena because of the method of presentation. Was executed valuation of the use such the maps in relation to the basic aims of the cartographical presentation. As illustrative examples were showed area cartograms.
THE UNIFIED GRAVITY REFERENCE SYSTEM OF THE POLISH PERMANENT GNSS NETWORK AND GEODYNAMIC NETWORKS – PART OF LOWER SILESIA
Tomasz Olszak, Andrzej Pachuta, Dominik Próchniewicz, Ryszard Szpunar, Marek Trojanowicz, Janusz Walo
geodynamic of Lower Silesia, gravity measurements
In years 2006–2007, at the area of Poland there were established a network of the absolute gravity measurements points for definition gravity reference system of the Polish Permanent GNSS network and geodynamic networks. Lower Silesian part of the system consist of five points situated in places: Wrocław, Kłodzko, Janowice Wielkie, Lubiąż i Świebodzice. The paper contain detailed description of location of the points Wrocław, Kłodzko, Janowice and Lubiąż, methods of monumentation and first results of measurements made at the points.