Inertial navigation system (INS) is a self-contained navigation technique. Its main purpose is to determinate the position and the trajectory of the object´s movement in space. This technique is well ...represented not only as a supplementary method (GPS/INS integrated system) but as an autonomous system for navigation of vehicles and pedestrians, also. The aim of this paper is to design a test for low-cost inertial measurement units. The test results give us information about accuracy, which determine the possible use in indoor navigation or other applications. There are described some methods for processing the data obtained by inertial measurement units, which remove noise and improve accuracy of position and orientation.
For the calibration of linear scales, comparators are generally used. Comparators are devices that enable the movement of an evaluation apparatus over a calibrated scale along a linear base with high ...precision. The construction of a comparator includes a movable carriage that carries the device for the evaluation of the position of the given edge of the line scale relative to the beginning of the scale. In principle, it involves a camera capturing the scale of the measurer, where the position of the camera's projection center is measured using an interferometer. This article addresses the development of a comparator assembled from low-cost components, as well as the description of systematic influences related to the movement of individual parts of the system, such as the inclination and rotation of the camera and directional and height deviations during the carriage's movement. This article also includes an evaluation of the edge of the given scale with subpixel accuracy, addressing distortion elimination and excluding the influences of impurities or imperfections on the scale. The proposed solution was applied to linear-scale measurers, such as leveling rods with coded and conventional scales and measuring tapes. The entire process of measurement and evaluation was automated.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
3.
PEDESTRIAN SAFETY AT CROSSINGS Kajánek, Pavol; Ondrejka, Roman
Acta Tecnología,
12/2015, Volume:
1, Issue:
2
Journal Article
Peer reviewed
Open access
The article deals with the evaluation of selected pedestrian crossings in terms of their functional parameters. Road safety is still a highly debated issue in all countries with a developed ...automobile transportation. Risk are the group of participants, with a team that drivers and passengers in motor vehicles are more or less protected by the vehicle itself, cyclists and motorcyclists are partially protected for example, helmet. But pedestrians are not protected at all. Thus pedestrian is the most vulnerable road users. In Slovakia, die each year from an average of 200 pedestrians. The most frequent causes of pedestrian accidents are the entrance to the roadway approaching the motor vehicle from the sidewalk and miscalculation when passing communication.
The focused effort of European Union in a form of safety improvement as one of the essential quality attributes of a transport system was reflected in several legal norms governing the conditions for ...each element of this system. Road infrastructure is no exception, where rules and principles of safety shall be applied in the process of its preparation, implementation and within the operation as well. The Directive 2008/96/EC on road infrastructure safety management has defined the basic framework for performance of individual procedures, which was transposed into national legislation and gained detailed outlines through adoption of the Act on road infrastructure safety management and related decrees.
The paper deals with the geodetic monitoring of a parabolic shaped reinforced con-crete roof structure in the chemical company Duslo, Ltd. in Šaľa (Slovak Republic).The monitored structure is a part ...of the roof of a warehouse used for the storage offertilizer. The atmospheric conditions and the operation load caused deformationof the construction. For measurement was used the technology of terrestrial laserscanning. The displacements of the observed parts of the construction were cal-culated using planar surfaces by the procedure of Singular Value Decomposition ofmatrixes. The procedure of initial and 2 epochal measurements of deformations,the procedure of the data processing, and the results of the deformation monitoringare described.
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.
Inertial measuring system (IMS) is a self-contained navigation system which enables monitoring of 3D position and orientation of the navigated object in indoor environment. Determination of the ...position and orientation of an IMS is based on integration process, where the displacement and the change of the orientation are calculated from inertial measurements (acceleration and angular rate). The measurements of inertial sensors are influenced by systematic errors, which are accumulated in the integration process. Accumulation of systematic errors causes exponential growth of position error, which is the main problem of IMS. The paper describes a measuring system designed for application in indoor environment. Sensory part of the measuring system consists of two IMS placed on common baseline and an optical encoder. The proposed measuring system uses two IMSs placed on a baseline, due to the fixed geometric relationships between the coordinate systems of both IMSs, which gives the corrections for the position and the orientation of the navigated object. The optical encoder measures the speed of movement of the navigated object, which is independent on the time of measurement that enables the elimination of systematic errors of accelerations obtained by IMS. The basic advantages of the proposed system are low-cost components, low-power requirements and independence on external signals. The proposed measuring system itself, the model of data processing and experimental measurements are described. The accuracy of the results is analyzed also.
The article deals with the developing and applying of the mobile mapping system developed at the Department of Surveying of the Slovak University of Technology in Bratislava. The article presents a ...low-cost mobile mapping system for simultaneous localization and mapping of the indoor environment. Existing systems are costly and have robust construction and high-power requirements, making them unavailable for some applications. The proposed measuring system consists of three orthogonally placed 2D lidars, a robotic platform with two rotary encoders, and an inertial measuring unit. The lidars scan the environment in three mutually perpendicular directions during the measurement. Based on the transformation between a pair of consecutive scans, the position of the system is updated. Then the model of the environment is updated using a new lidar scan. The estimated transformation parameters are translations expressing the change in position of the system and rotation, which represents the change in orientation of the measuring system. The errors in determining the transformation parameters represent the positioning errors, which are transmitted to the calculated model. For this reason, additional sensors are used (inertial measuring unit, speed sensors), based on which the error in position and orientation is corrected.
Indoor navigation (navigation in an indoor environment) presents a new challenge in the field of personal navigation systems. Although there are a lot of options available for creation of a ...navigation system, only a few of them satisfy the requirements of users in terms of accuracy. Systems based on ultrasound (US) technology provide accurate positioning also in an indoor environment, where other navigation techniques (e.g. GNSS) are not available. Properties of the ultrasound (frequency over 20 kHz) combine several advantages that make it an attractive technology for indoor navigation. Its advantages include low financial cost, slow speed of the signal (about 344 m / s, depending on the temperature), low energy demand, low material absorption, or the accurate determination of the relative position (order of 10-2m). This paper presents an ultrasound based indoor positioning system developed at the Department of Surveying, Faculty of Civil Engineering SUT in Bratislava.
The paper deals with height determination in indoor environment using inertial sensors (accelerometers, gyroscopes) and barometer built in a smartphone, which is very important to detect upstairs and ...downstairs motion of the users. The algorithm proposed uses the barometric formula for height determination and the relationship between the decreasing barometric pressure and increasing height. The main advantage of the use of barometer is the long-term accuracy, because the algorithm is not recursive. The problem of the barometric measurement lies in the local disturbances of barometric pressure which is caused by temperature changes (increasing temperature cause increase of the pressure) and instable air mass (air-conditioning cause inhomogeneous air mass). These local disturbances of the barometric pressure lead to increase of errors in height determination. Reduce the errors caused by the temperature change, accelerometer data using step detection with average step height (without integration process), are used. Double integration of the acceleration measured is used only in specific situations (only in case when elevator is used during the movement). The benefit of the use of combined processing of barometer and accelerometer data against the use of only barometer or accelerometer data is analyzed on the base of experimental measurements.
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