Monitoring of Building Structure by Tiltsensors

This paper discusses about the dynamic monitoring of stability (tilt measurement) of bearing pillar of high-rise building using the electronic measuring system. The electronic measuring system consists of Libela 2800 tilt sensor, input/output device for the AE 2DN tilt sensor, measuring amplifier and also the Spider8 analog/digital converter and the registration equipment (notebook). The basic part of uniaxial tilt sensor creates a frame, on which is among damping plates hung a pendulum (ferromagnetic kernel). The tilt value is determined on a principle of electromagnetic induction by changing the position of ferromagnetic kernel in the reel. The range of pendulum movement is ± 2,5 mm/m and the accuracy of the tilt determination is 0,001 mm/m. The monitored building represents, from the point of constructional view, a ferro-concrete rectangular sceleton, which consists of vertical bearing pillars, on which are guyed longitudinal and transverse girders. The building ground-plan is rectangular with the dimensions of 75 m (distance) and 12 m (width). The building has two underground and six above the ground floors with constructional high of 3,40 m. Whole highth of the above ground part of building is 20,4 m. The pillar tilt was measured in the transverse direction of the building at the level of the second floor using the Libela 2800 electronic sensor. The sensor was situated on the metallic console (L-profile), which was assembled on a lateral side of the circuit bearing pillar at the highth of 8,3 m above the ground level. Together with the tilt monitoring, the outside air temperature in the close area of pillar was measured. The tilt measurement was carried out continuously for 168 hours with the recording frequency of 1 Hz (1 measurement/second). The file of the measured data with 603 950 records was reduced to the file with 1006 records, which corresponds to the record of the every tenth minute. The measured tilt values represent from the mathematical point of view, a time series. The time series of the measured value is a sum of the trend, seasonal, cyclic and the stochastic component. By the application of time series analysis using the regression method and the Box-Jenkinson methodology, we decompose systematic components and isolate stochastic errors, which rise by the measurement. Individual components of time series are expressed mathematically as a function of time. A precise and exact mathematic-statistical data processing guarantees the definite coefficient estimation of the time series function and enables a correct interpretation of results. The difference between the initial and the final tilt value in a range of measurement (168 hours) is 0,218 mm/m and the relative transverse movement of pillar (building) at the highth of 8,3 m would reach the value of 1,81 mm

Plane segmentation from point clouds

Recently, attempts have been made to automate data acquisition, which is also related to efforts to automate data processing. The paper deals with the automation of terrestrial laser scanning data processing. The approaches for point cloud segmentation are briefly described. An algorithm based on random sample consensus is proposed for automated plane identification and plane segmentation from point clouds. The proposed approach was tested by processing point clouds; the results of the testing are also described. Based on the proposed algorithm, a standalone application for automated plane segmentation from laser scanner data using Matlab® software was developed

Barcode based localization system in indoor environment

Nowadays, in the era of intelligent buildings, there is a need to create indoornavigation systems, what is steadily a challenge. QR (Quick Response) codesprovide accurate localization also in indoor environment, where other navigationtechniques (e.g. GPS) are not available. The paper deals with the issues of posi-tioning using QR codes, solved at the Department of Surveying, Faculty of CivilEngineering SUT in Bratislava. Operating principle of QR codes, description ofthe application for positioning in indoor environment based on OS Android forsmartphones are described

Pozicioniranje i praćenje pješaka u zatvorenom prostoru koristeći senzore pametnih telefona, otkrivanje koraka i algoritam za geokodiranje

The paper deals with indoor navigation using inertial sensors (accelerometers, gyroscopes, etc.) built in a smartphone. The main disadvantage of the use of inertial sensors is the accuracy, which rapidly decreases with the increasing time of the measurement. The reason of the deteriorating accuracy is the presence of errors in inertial measurements, which are accumulated in the integration process. The paper describes the determination of a pedestrian trajectory using step detection method, which is improved with utilization of the adaptive step length estimation algorithm. This algorithm reflects the change of the step length with different types of movement. The proposal of the data processing uses information from floormap, what allows the verification of the pedestrian position and detects the collision of the trajectory with the floormap. The proposed algorithm significantly increases the accuracy of the resulting trajectory. Another extension of the proposed algorithm is the implementation of the barometer measurements for determination of the height differences. This fact allows change the floor in a multi-storey buildings. The experimental measurement was realized with a smartphone Samsung Galaxy S4.Rad se bavi navigacijom u zatvorenom prostoru koristeći inercijalne senzore (akcelerometre, žiroskope, itd.) ugrađene u pametne telefone. Najveći nedostatak korištenja inercijalnih senzora je netočnost koja se ubrzano povećava produljenjem vremena mjerenja. Razlog smanjenja točnosti je prisutnost pogrešaka inercijalnih mjerenja koje se akumuliraju kroz proces integracije. Rad opisuje određivanje putanje pješaka koristeći metodu praćenja koraka koja je poboljšana korištenjem algoritma za procjenu prilagodljive duljine koraka. Ovaj algoritam odražava promjene u duljini koraka s različitim vrstama kretanja. Prijedlog obrade podataka koristi informacije iz tlocrta katova što omogućava potvrdu položaja pješaka i otkriva koliziju putanje s tlocrtom. Predloženi algoritam znatno povećava točnost dobivene putanje. Drugi dodatak predloženog algoritma se odnosi na upotrebu barometarskih mjerenja pri određivanju visinskih razlika. Ova činjenica omogućava promjenu kata u višekatnoj zgradi. Eksperimentalno mjerenje je izvršeno uz pomoć pametnog telefona Samsung Galaxy S4

70 rokov výučby geodézie a kartografie na Stavebnej fakulte STU v Bratislave =70 Years Surveying Education at the Faculty of Civil Engineering of the STU in Bratislava

The history and the development of the surveying education at the STU in Bratislava. Development of study programmes, institutes and departments responsible for surveying education. Harmonisation process in Slovakia and the European countries. State of the art of the university surveying education in Slovakia20120

Warm-Up Effect and Warm-Up Time of a Laser Tracker

The warm-up effect is a well-known phenomenon, which occurs in all types of laser trackers. The series of experiments was performed to determine the influence of warm-up effect on measurement and a warm-up time of device – the time after the temperature inside the tracker is stable. In this paper, the tested tracker was Leica AT960-MR. Results showed that the warm-up effect could cause errors up to tenths of millimeters, and a warm-up time of instrument is around two hours, which is similar to the other researches

Improvement of the Accuracy of the Orientation of an Object by Using a Pair of Rotating IMS

Inertial measurement systems (IMS) belong among navigation systems which permit the monitoring of the position and orientation of an object in three-dimensional space. The functional principle of IMS is based on the integration of the output signal (acceleration and angular rate) of inertial sensors to the actual position and orientation of IMS. This integration causes the rapid accumulation of systematic IMS’s errors, which leads to a rapid increase in position and orientation errors over time. The paper deals with the design of a prototype for a pair of lowcost IMSs, which are regularly rotated around their vertical axis by stepper motors. To eliminate the systematic errors of gyroscopes in the direction of the rotation axis, two counter-rotating IMSs are used. An optimal model of the data processing was developed and presented

Error Sources and Models of the Laser Tracker without a Beam Steering Mirror

The laser tracker is a widely used instrument in many industrial and metrological applications with high demand measurement accuracy. Imperfections in construction and misalignment of individual parts deliver systematic errors in the measurement results. All error sources need to be identified and reduced to the minimum to achieve the best possible accuracy. The paper summarizes error sources of the laser tracker without beam steering mirror with emphasis on error modeling. Descriptions of error models are provided for the static and kinematic type of measurement

Initial Suggestions of Optimal Configuration of Standpoints in the application of Laser Terrestrial Scanners

The aim of this paper is to point at several aspects, which are important by an optimal configuration project of TLS standpoints. The scanning accuracy is influenced by uncertainties in the distance and angle determination as well as by uncertainties resulting from the point transformation into one block. The accuracy measurement analysis at one standpoint anticipates the creation of the mathematical model of the optimal standpoint configuration by the application of TLS. The angle uncertainties (ασ) have been changed step by step to determine the influence of the distance on the 3D point determination by applying of several variants and causes, resulting in the summary 3D graphical interpretation of results by using of B-spline surfaces in the Surfer 8 and Microstation SE software. All analyses were realised for the HDS 2500 terrestrial laser scanner. In the end of this paper, on a base of the former analyses, suggestions are described how it is possible to locate the suitable scanner standpoint to achieve a required accuracy in the 3D determination of the point position on the scanned object