A Comparative Study of Signal Processing Methods for Contactless Geodetic Monitoring

Building structures are subject to various deformations caused by external and internal factors. Deformations are determined by various methods in the form of monitoring. It is very important to monitor the dynamic vibration response on bridge structures since these measurements allow us to identify any possible damage over time and take appropriate action. Our experiment, described in this article, is based on the use of non-contact methods, among which we used a geodetic instrument RTS (Robotic Total Station) and a seismograph to measure vibrations. The purpose and novelty of our work are reflected in the use of geodetic instruments to determine the dynamic response and synchronization of the obtained results. When using RTS technology, we increased data acquisition from 9 to 26 measurements per second. Comparative analysis of the measured signals was performed using FFT (Fast Fourier Transformation) and LSP (Lomb–Scargle Periodogram), based on LSSA (Least-Squares Spectral Analysis). The results showed us that when using the RTS geodetic instrument, it is possible to achieve frequency spectra comparable to those measured with a seismograph instrument. By increasing the number of measurements, the RTS method can be used to obtain more continuous data, which are essential for dynamic analyses.

Applicability and Analysis of the Results of Non-Contact Methods in Determining the Vertical Displacements of Timber Beams

Determining the displacements and consequent deformations of structures is a demanding branch of engineering. Displacements are most often determined by geodetic methods, among which high-precision non-contact methods have recently taken the lead. Engineering geodesy is an indispensable part of construction projects. In the desire for efficient and fast measurements, the technology of terrestrial laser scanning (TLS) and the use of robotic total station (RTS) and other geodetic methods are becoming more and more useful for engineers. In the presented study, we focused on the measurement and comparison of vertical displacements with various mentioned equipment and the determination of the influence of meteorological conditions on the displacements of timber beams that we used to perform the experiment. Measurements were performed both in the laboratory and outdoors. A novelty in the work was the use of a TLS scanner to determine the evaluation of small value displacements and the analysis of the usability of geodetic measuring equipment. In the Materials and Methods section, we describe the equipment used and the characteristics of the beams. The Results section describes the experimental outcomes, which include the performance of experimental analysis of vertical displacements of timber beams under different meteorological conditions. Altogether, the results consist of geodetic measurements and the processing of measured data. The results of measurements of vertical displacements with a terrestrial laser scanner were compared with the results obtained with a robotic total station were evaluated and compared with the displacements calculated from static analysis and the results of other methods used.

Analysis of a kinematic real-time robotic total station network for robot control

The use of robots is widespread in the field of construction nowadays. Robots may be mobile or static depending on the specific task or application. One of the major challenges when implementing mobile robots is localisation. In the field of robotics, localisation is often performed in a relative sense, however some applications require absolute localisation. In order to provide absolute positions, appropriate sensors such as Global Navigation Satellite Systems (GNSS) or total stations can be employed. The underlying task is embedded within the Germany´s Excellence Strategy “Integrative Computational Design and Construction for Architecture (IntCDC)” funded by the German Research Foundation (DFG). The specific sub-project deals with issues of robot-robot collaboration and specifically aims the provision of absolute position and orientation, designated as pose, of a mobile construction robot. The determined pose information supports different control loops of the robot including automated driving, steering and tool operations. The choice of the sensor system favoured a robotic total station (RTS), because of its real-time capability and measurement accuracy. The measurement system is coupled with an Inertial Measurement Unit (IMU) for orientation. To counteract line-of-sight interference between the RTS and the target, the contribution proposes the use of a network of four spatially evenly distributed RTSs. The quality characteristics of different pose determination procedures of a mobile construction robot are investigated using methods from the geodetic network theory. Conclusions about accuracy and reliability distribution across the construction site are presented numerically and graphically.

SISTEM PERINGATAN DINI: PEMANTAUAN LERENG TAMBANG MENGGUNAKAN APLIKASI TELEGRAM

Metode pemantauan lereng menggunakan prisma merupakan salah satu metode yang masih diandalkan, salah satu alat yang digunakan untuk pick up data dari prisma adalah Robotic Total Station (RTS). RTS merupakan salah satu alat pantau kestabilan lereng secara real time di area tambang terbuka. Namun data tersebut masih belum bisa digunakan sebagai sistem peringatan dini untuk menyampaikan status pergerakan. Selain itu, kendala lainnya adalah keterbatasan personel untuk dapat memonitoring RTS selama 7x24 jam karena kurva yang dihasilkan masih bersifat kualitatif, sehingga masih membutuhkan interpretasi oleh seorang kompeten untuk menentukan pola pergerakan dan status lereng. Untuk membuat sistem peringatan dini diperlukan adanya nilai kuantitatif ambang batas sebagai acuan status pergerakan lereng, penentuan nilai ambang batas haruslah sesuai dengan kondisi aktual dilapangan sehingga tidak terjadi false evacuate alarm dan late evacuate alarm. Poin lainnya adalah media komunikasi yang dapat digunakan secara masif di lokasi pekerjaan agar penggunaan sistem peringan dini ini dapat efektif diterapkan. Dengan menggunakan metode penelitian tindakan dan dengan pendekatan four-D maka didapatlah suatu sistem yang dapat digunakan sebagai sistem peringatan dini deteksi pergerakan lereng tambang menggunakan aplikasi Telegram yang dapat berjalan pada perangkat mobile Android dan IOS. Hasil penelitian didapatkan bahwa data pengamatan RTS dapat dikonversi menggunakan bahasa pemrograman PHP dan database MySQL sehingga dapat diteruskan oleh sistem API dengan bantuan Bot pada aplikasi Telegram untuk menampilkan informasi berupa total movement (cm), velocity (cm/hari) dan status lereng pada chat group yang dapat menentukan tindakan selanjutnya yang akan dilakukan.

Point-Cloud Models of Historical Barns – Spatial Discrepancies of Laser Scanning versus Robotic Total Station

This study considers the generation of virtual, 3D point-cloud models of seven deteriorating historical, agricultural barns in Bulloch County, Georgia, USA, for preservation purposes. The work was completed as a service-learning project in a course on Terrestrial Light Detection and Ranging (T-LiDAR), offered at Georgia Southern University. The resulting models and fly-through videos were donated to Bulloch County Historical Society and to the Georgia Southern Museum, to make them available to the general public and future generations. Additionally, one of the seven barns was selected to be extensively measured to estimate the relative spatial accuracy of all seven resulting 3D point-cloud models, with respect to measurements completed with a highly accurate instrument. Three accurate benchmarks were established around it for georeferencing purposes. The positions of 44 points were measured in the field via an accurate, one- second, robotic total-station (RTS) instrument. Also, the coordinates of the same points were acquired from within georeferenced and non-georeferenced point-cloud models. These points defined 259 distances. They were compared to determine their discrepancy statistics. It was observed that this process produced virtual models with an approximate maximum spatial discrepancy of one-half inch (0.5 in) with respect to measurements performed by a highly accurate RTS device. There were no substantial differences in the relative accuracies of the georeferenced and non-georeferenced models.

Non-contact monitoring for assessing potential bridge damages

Structural monitoring of objects is primarily executed to assess external and internal effects on the object, in order to ensure the safety of people, animals, and material assets. Such monitoring can be executed through various methods, depending on the object, conditions for execution, and purpose of the monitoring. In this case, the focus is on the execution of the monitoring of Maribor footbridge, where the dynamic effects of the object are monitored. For this purpose, geophone, accelerometer, and geodetic methods—using Global Navigation Satellite System (GNSS) and Robotic Total Station (RTS) equipment—are used, of which one is controlled by the additional programme GeoComZG. The emphasis of our experiment is on the application of non-contact geodetic methods, with which the measurements of dynamic response are typically performed, as they enable measurements up to 30 and 100 Hz with RTS and GNSS, respectively. In this article, the application of various procedures of non-contact data capture on the footbridge are detailed and a comparison and analysis of the obtained values for monitoring the dynamic response of the structure are presented.