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Rockfall phenomena are considered highly dangerous due to their rapid evolution and difficult prediction without applying preventive monitoring and mitigation actions. This research investigates a hazardous site in the Municipality of Vecchiano (Province of Pisa, Italy), characterized by vertical rock walls prone to instability due to heavy fracturing and karst phenomena. The presence of anthropical structures and a public road at the bottom of the slopes increases the vulnerability of the site and the site's risk. To create a comprehensive geological model of the area, Unmanned Aircraft System (UAS) photogrammetric surveys were conducted to create a 3D model useful in photointerpretation. In accessible and safe areas for personnel, engineering–geological surveys were carried out to characterize the rock mass and to define the portion of rock walls to be monitored. Results from nine multitemporal Robotic Total Station (RTS) measurement campaigns show that no monitoring prisms recorded significant displacement trends, both on the horizontal and vertical plane and in differential slope distance. Additionally, satellite Persistent Scatterer Interferometry (PSI) analysis indicates that the slopes were stable over the two years of study. The integration of these analysis techniques has proven to be an efficient solution for assessing slope stability in this specific rockfall-prone area. [ABSTRACT FROM AUTHOR]

The development of multi-sensor systems (MSSs) goes hand in hand with assessing the quality of these complex systems. Therefore, reliable reference information of superior accuracy is essential for validation, serving as ground truth. When the assessment is based on 3D point cloud comparison, appropriate reference environments with suitable geometries are required. However, validation of an MSS can also be performed directly on its 3D position or even its 6D pose. This is particularly suitable for systems without sensors for environmental acquisition. When using kinematic measurement systems, the temporal relationship between the MSS and the reference trajectory must be considered, which can be challenging. Modern sensors of an MSS are often synchronized to GPS time. However, this global time information is not provided for high-accuracy tracking sensors such as robotic total stations (RTSs) or laser trackers (LTs). Instead, only a reference to an internal sensor time is implemented, which does not meet the highest quality requirements for reference trajectories. Depending on the motion speed, time offsets in the millisecond range can lead to significant trajectory inaccuracies. This paper presents investigations for GPS time synchronization of the polar measurement elements of both RTS and LT from Leica Geosystems. While the LT uses a precise trigger signal for the time link, the RTS requires the Measure & Stream application provided by the instrument manufacturer. The two different approaches are presented theoretically. Based on empirical long-term studies, their possibilities and limitations are critically discussed. For the high-frequency LT, reference trajectories with precise synchronization based on GPS time can be reliably realized. With an RTS, improved synchronization can be achieved by using Measure & Stream. Thus, 43 % lower tangential deviations from the reference could be achieved compared to the raw data. However, there are still inconstant time offsets of 63.9 ms on average. Depending on the speed of the target, this can lead to significant position deviations. Further investigations are required. In general, the developed approaches for the realization of GPS-synchronized reference trajectories can be used not only for the quality assessment of MSS, but also for monitoring or kinematic positioning applications. [ABSTRACT FROM AUTHOR]

The total station is the most basic geodetic measuring instrument, locally the most accurate and versatile. Its accuracy is the cornerstone of its use and is defined by the standard deviations of horizontal direction, zenith angle and slope distance measurements. These accuracy parameters are given by the manufacturer, but these are only valid under optimum measurement conditions. To ensure the credibility and reliability of the measurements, these values must be periodically ascertained or determined for atypical measurement configurations or measurement conditions. Standardised procedures are used for this purpose, but in our opinion, they do not reflect the full influence of the measuring conditions and other measuring aids. A comprehensive determination of the accuracies (variation components) from the alignment, where all possible influences in a given situation are applied, may be considered the most appropriate for determining the angular accuracy of measurements. Such atypical conditions are certainly represented by geodetic measurements in the confined spaces of an underground mine. Thus, an experimental determination of the accuracy of four different robotic total stations was carried out at the Center of experimental geotechnics in a mine Josef teaching centre (CTU in Prague), and the Frstner method was used to determine the variation components. A network of 6 stations and 8 target points was designed. The grid size was approximately 32x21 m with 4 - 31 m lengths. A network with the same configuration was also duplicated at the surface to assess whether the accuracy is different in underground and how the results will correspond to the accuracy claimed by the manufacturers. The result of the testing is that the accuracy claimed by the manufacturers is maintained even under such difficult measurement conditions in narrow corridors and with short sights. The overall evaluation also found that the accuracy achieved underground and on the surface is identical, although it varies from instrument to instrument. [ABSTRACT FROM AUTHOR]

Earth flows are complex gravitational events characterised by a heterogeneous displacement pattern in terms of scale, style, and orientation. As a result, their monitoring, for both knowledge and emergency purposes, represents a relevant challenge in the field of engineering geology. This paper aims to assess the capabilities, peculiarities, and limitations of different remote sensing monitoring techniques through their application to the Pietrafitta earth flow (Southern Italy). The research compared and combined data collected during the main landslide reactivations by different ground-based remote sensors such as Robotic Total Station (R-TS), Terrestrial Synthetic Aperture Radar Interferometry (T-InSAR), and Terrestrial Laser Scanner (TLS), with data being derived by satellite-based Digital Image Correlation (DIC) analysis. The comparison between R-TS and T-InSAR measurements showed that, despite their different spatial and temporal resolutions, the observed deformation trends remain approximately coherent. On the other hand, DIC analysis was able to detect a kinematic process, such as the expansion of the landslide channel, which was not detected by the other techniques used. The results suggest that, when faced with complex events, the use of a single monitoring technique may not be enough to fully observe and understand the processes taking place. Therefore, the limitations of each different technique alone can be solved by a multi-sensor monitoring approach. [ABSTRACT FROM AUTHOR]

TLS is nowadays often used for deformation monitoring. As it is not able to scan identical points in different time epochs, mathematical models of objects derived from point clouds have to be used. The most common geometric form to describe built objects is a plane, which can be described by four parameters. In this study, we aimed to find out how small changes in the parameters of the plane can be detected by TLS. We aimed to eliminate all possible factors that influence the scanning. Then, we shifted and tilted a finite physical representation of a plane in a controlled way. After each controlled change, the board was scanned several times and the parameters of the plane were calculated. We used two different types of scanning devices and compared their performance. The changes in the plane parameters were compared with the actual change values and statistically tested. The results show that TLS detects shifts in the millimetre range and tilts of 150″ (for a 1 m plane). A robotic total station can achieve twice the precision of TLS despite lower density and slower performance. For deformation monitoring, we strongly recommend repeating each scan several times (i) to check for gross errors and (ii) to obtain a realistic precision estimate. [ABSTRACT FROM AUTHOR]

Despite the increasing interest in kinematic data acquisition, Robotic Total Stations (RTSs) are still relatively seldom used. No matter if Mobile Mapping Systems or Control & Guidance, GNSS is mostly used as position sensor, which limits the application to outdoor areas. For indoor applications, a combination of relative sensors is usually employed. One reason why RTSs are not used is the challenging time referencing and synchronization. In this work we analyze the challenges of a synchronized kinematic application of RTSs and present solutions. Our approach is based on a wireless network synchronization to establish a precise temporal reference frame. The achievable synchronization quality is thoroughly examined. In addition we develop a kinematic model of spherical measurements, that incorporates timing related parameters. To estimate these parameters we propose a temporal calibration utilizing an industrial robot. Both parts of our approach are evaluated using a test setup of two total stations, proofing an overall synchronization accuracy of 0.2 ms. An overall horizontal kinematic point accuracy of 2.3 mm reveals the potential of sufficiently synchronized RTSs. [ABSTRACT FROM AUTHOR]

Building construction is the subject of various factors and their consequences must be regularly monitored; this can be carried out in the form of control measurements or monitoring. This article aims to show the usability of geodetic non-contact methods in defining the dynamic response of structures. The lamella on which various methods for monitoring the dynamic response was used for simulation; the emphasis is on a modern geodetic method using a Robotic Total Station (RTS). To determine the dynamic response, the algorithm for the determination of the harmonic oscillation's average amplitude and the methods of the spectral analysis of the sampled data is further described. The results obtained with the RTS method have shown a high level of reliability for the determination of dynamic response. [ABSTRACT FROM AUTHOR]

Our proposal for this paper is to identify and introduce topographic methods and technologies to ensure the best monitoring of buildings of vital importance for society or those with significant structural damage due to compaction of soil. The main purpose of this study is to find and compare contemporary methods that have been developed in recent years and are used in applied topography, replacing traditional methods successfully. Recently, digital technology has evolved at the same time with society needs and development. The use of 3D laser scanner, combined GPS stations, laser or photogrammetric scanning, total or modern robotic stations and drones, appear to be the most suitable solutions nowadays. A comparative research using different scientific papers will be presented in a short table. Each method is described with its advantages and disadvantages. [ABSTRACT FROM AUTHOR]

High sampling-rate robotic total stations (RTS) are emerging tools for monitoring both semi-static and dynamic displacement responses of bridge structures, due to rapid advancements in data sampling rates and tracking speeds. However, the dynamic measurement accuracy of the RTS needs to be fully assessed, especially for different sighting distances. To this end, groups of static and dynamic evaluating tests were carried out on university campuses, and a further in-situ performance assessment with RTS was performed for monitoring dynamic responses of a long suspension bridge in Changsha, China, with a central span of 328 m. A standardized procedure was developed to process these RTS measurements. The background noise in RTS measurements for sighting-distances varying from 25 m to 400 m only results in minor errors which mainly distribute in a frequency range of less than 0.1 Hz. The vibration displacements of an oscillating platform between the RTS and an accelerometer are compared in both horizontal and vertical directions to demonstrate the sufficient accuracy of the RTS measurements. The in-situ experiment also leads to a similar conclusion. This study confirms that the feasibility of using high sampling-rate RTS for monitoring dynamic responses of bridges. [ABSTRACT FROM AUTHOR]

Robotic total stations (RTS) are frequently used for the measurement of temperature induced bridge deformations or during load testing of bridges. In experimental setups, total stations have also been used for the measurement of dynamic bridge deformations. However, with standard configurations the measurement rate is not constant and on average an update rate of 7-10Hz can be achieved. This is not sufficient for the vibration monitoring of bridges considering their natural frequencies which are also in the same range. In this paper, we present different approaches to overcome these problems. In the first two approaches we demonstrate how the measurement rate to prisms can be increased to 20Hz to determine vertical deformations of bridges. Critical aspects like the measurement resolution of the automated target tracking and the correct sequence of steering commands are discussed. In another approach we demonstrate how vertical bridge vibrations can be measured using an image assisted total station (IATS) and corresponding processing techniques. The advantage of image-based methods is that structural features of a bridge like bolts can be used as targets. Therefore, no expensive prisms have to be mounted and access to the bridge is not required. All approaches are verified by laboratory investigations and their suitability is proven in a field experiment on a 74m long footbridge. In this field experiment the natural frequencies derived from the total station measurements are compared to the results of accelerometer measurements. [ABSTRACT FROM AUTHOR]

Modern robotic total stations (RTS) have the ability to automatically aim, search and track moving targets at high precision thereby enabling kinematic positioning. However, the internal subsystems of the RTS (distance and direction) exhibit time delays which limit the precision positioning of a moving target. These effects are investigated with tracking experiments on a known circular and linear path. A second part of this research investigates small-scale unmanned aerial vehicles (UAV) which use navigation quality GPS as a priori coordinates for photogrammetric processing of acquired images. RTS kinematic positioning was applied to a UAV in a field trial to improve a priori image coordinates and evaluate the method for direct geo-referencing. [ABSTRACT FROM AUTHOR]

Urban tunnel projects such as new metro lines face particular challenges. Shallow overburden, difficult (hydro)geological conditions and sensitive buildings in close proximity are risks that often cannot be avoided, demanding large and complex geotechnical monitoring programmes. This paper considers the current situation of tunnel monitoring in urban environments and describes two specific monitoring solutions, one for shafts and one for structures, and emphasises the importance of efficient data management with the assistance of a tunnel information system. Finally, the paper gives an overview of recent research activity and emerging sensing technologies. [ABSTRACT FROM AUTHOR]

Accurate slope stability analysis is essential for human activity in high-risk geological contexts. This may, however, not be enough in the case of quarrying where the dynamic and evolving environment also requires effective monitoring. A well-designed monitoring system requires the acquisition of a huge dataset over time, improving knowledge of the study area and helping to refine prediction from stability analysis. This paper reports the implementation of an integrated monitoring system in a marble quarry in the Apuan Alps (Italy) and some of the results obtained. The equipment consists of a traditional geotechnical monitoring system (extensometers, crackmeters and clinometers) and two modern topographic monitoring systems (a terrestrial interferometer and a robotic total station). This work aims to provide in-depth knowledge of the large scale rock mass behaviour as a result of marble exploitation, thereby allowing continuous excavation. The results highlight the importance of integrating different monitoring systems. [ABSTRACT FROM AUTHOR]

In the field of landslide monitoring, the assessment of the spatially-distributed three-dimensional surface displacement is crucial to understand the underlying mechanisms. Nevertheless, available technologies and techniques that provide such a datum are few and often suffer spatio-temporal resolution, logistic and/or financial limitations. In this framework, we developed a methodology that merges the three-dimensional measurements at specific points, acquired by a robotic total station (RTS), and the spatially-distributed data obtained with digital image correlation (DIC) of time-lapse camera photographs, to achieve the spatially-distributed three-dimensional surface displacement. The integration method follows this procedure: i) the DIC results are orthorectified on an existing digital elevation model; ii) the RTS data are rototranslated into the camera coordinate system; iii) the ratio α between displacement vertical component and module measured by the RTS is calculated and interpolated across the region of interest; iv) the orthorectified DIC results are rescaled according to α , obtaining the three surface displacement components; v) the displacement vector is rototranslated into the geographical coordinate system. The sensitivity analysis respect to α revealed that the integration method can be successfully applied even with a limited number of RTS measurement points. The developed methodology has been applied to the Mont de La Saxe rockslide case study, during a phase of strong acceleration. In this period, the displacement magnitudes varied between 0.1 m and 10 m, thus providing a stress-test input for methodology development and validation. The results have been compared with independent ground-based interferometric radar measurements, obtaining 0.99 linear correlation coefficient and median absolute deviation of 0.086 m, which is comparable with the DIC measurement uncertainty. The proposed method is based on the use of low-cost portable and commonly used field equipment, thus it can be easily implemented in existing monitoring networks without additional financial costs. • We developed a data fusion algorithm to merge digital image correlation and robotic total station. • We obtained spatially distributed 3D surface displacement of a landslide. • Our method can be easily applied in operative monitoring without additional financial costs. • We tested our method on the Mont de La Saxe rockslide (Italy), during an emergency period. • We validated our results with GB-InSAR obtaining high agreement. [ABSTRACT FROM AUTHOR]

Abstract: Emerging wireless remote sensing technologies offer significant potential to advance the management of construction processes by providing real-time access to the locations of workers, materials, and equipment. Unfortunately, little is known regarding the accuracy, reliability, and practical benefits of an emerging technology, effectively impeding widespread adoption. This paper evaluates a commercially-available Ultra Wideband (UWB) system for real-time, mobile resource location tracking in harsh construction environments. A focus of this paper is to measure the performance of the UWB technology for tracking mobile resources in real-world construction settings. To assess tracking accuracy, location error rates for select UWB track signals are obtained by automatically tracking a single entity using a Robotic Total Station (RTS) for ground truth. Furthermore, to demonstrate the benefits of UWB technology, the paper provides case studies of resource tracking for analysis of worksite operations. The work demonstrates the applicability of UWB for the design of construction management support tools. [Copyright &y& Elsevier]

Abstract: Analysis and understanding of worksite operations requires the collection of trajectory information regarding active onsite entities. The trajectories provide essential information for assessment of site operations and management strategies. Unfortunately, many such tracking and assessment methods are based on manually generated trajectories, thereby excluding long term and complex scenarios. Automated trajectory extraction is a potential solution, however the automated method must provide reliable trajectory information. This paper evaluates the capability of two sensor technologies to provide accurate trajectory data. The primary system investigated is a vision-based strategy while the secondary system investigated is an Ultra Wideband System (UWB). A robotic total station (RTS) provides the ground truth of a single worker for evaluation of both sensor technologies. For comparison, the visual tracking signal is mapped to three-dimensional world coordinates. The UWB and RTS signals are filtered to remove outliers, and are synchronized with the visual tracking signal. Given the single target tracked by the RTS, both UWB and vision are shown to be feasible when the expected accuracy is 1m. A second investigation seeks to demonstrate the accuracy of the proposed visual tracking system for tracking multiple interacting workforce, which relies on machine learning to generate target descriptions. The UWB signals for the personnel provide ground truth to evaluate the reliability and accuracy of the vision-based tracking algorithm. The proposed visual tracking system is reliable and accurate enough to permit automated extraction of trajectory information for analysis purposes, such as would be required for work sampling and productivity assessments. [Copyright &y& Elsevier]

Abstract: The aim of the present work is to assess and to demonstrate the benefits of adopting optimal experimental design theory and techniques in order to enhance the potential of field data recorded using conventional geodetic instruments. More specifically, this research focuses on Robotic Total Stations (RTS) and in kinematic applications of geodetic positioning that exhibit a cyclic/periodic pattern of motion. The computational approach adopted follows from the principles of c- and D-optimal design criteria. Data processing involves computing the amplitude of motion in two ways; (a) using a sample of consecutively ordered data recordings and (b) using a sample respecting the optimal design criteria. Analysis, confirms the utility of the method resulting an improvement (i.e. a reduction) of the oscillation amplitude variance. This conclusion applies particularly at higher frequencies of oscillations (>1Hz). This is important as at higher frequencies the performance of RTS deteriorates, and hence large variances occur. [ABSTRACT FROM AUTHOR]

Nowadays volume values are used in many engineering studies, such as road projects, mining enterprises, geological works and building applications. A volume can be computed by geodetic, trapezoidal and improved methods such as Simpson-based, cubic spline, and cubic Hermite formula. These improved methods model the object surface as nonlinear profiles. As the associated technology has developed then so have the opportunities for the development of new techniques in surface modelling. Now, the generation of a three-dimensional (3D) model is generally achieved by non-contact systems based on light waves and can be completed on a computer. This is particularly useful in situations where there are risks attached to reaching the location to be modelled - the calculations can be performed from a photograph or from scanned images of the object. In this study the performance of a laser scanning method, robotic total station instrument and geodetic method of volume computation were investigated. The volume computation was carried out using these methods in an excavation area and the methods were compared in terms of accuracy, time and cost. It was concluded that all the methods can satisfactorily be used for volume computing; however, the choice of method should be made according to the location and size of area, required accuracy, budget and time frame. [ABSTRACT FROM AUTHOR]

To validate the accuracy and reliability of onboard sensors for object detection and localization for driver assistance, as well as autonomous driving applications under realistic conditions (indoors and outdoors), a novel tracking system is presented. This tracking system is developed to determine the position and orientation of a slow-moving vehicle during test maneuvers within a reference environment (e.g., car during parking maneuvers), independent of the onboard sensors. One requirement is a 6 degree of freedom (DoF) pose with position uncertainty below 5 mm (3σ), orientation uncertainty below 0.3° (3σ), at a frequency higher than 20 Hz, and with a latency smaller than 500 ms. To compare the results from the reference system with the vehicle's onboard system, synchronization via a Precision Time Protocol (PTP) and system interoperability to a robot operating system (ROS) are achieved. The developed system combines motion capture cameras mounted in a 360° panorama view setup on the vehicle, measuring retroreflective markers distributed over the test site with known coordinates, while robotic total stations measure a prism on the vehicle. A point cloud of the test site serves as a digital twin of the environment, in which the movement of the vehicle is visualized. The results have shown that the fused measurements of these sensors complement each other, so that the accuracy requirements for the 6 DoF pose can be met while allowing a flexible installation in different environments. [ABSTRACT FROM AUTHOR]

• Use moving control point to determine the position and orientation. • Design a collaborative measurement system of Robotic Total Station and UAV. • Develop an algorithm to get optimation estimation of undetermined parameters. • Accuracy of coordinate and azimuth can reach mm and seconds within minutes. • The method can be applied in many situations with poor observation conditions. We have developed a system to determine the position and orientation fast and precisely, by the collaboration measurement of an Unmanned Aerial Vehicle (UAV) and two Robotic Total Stations (RTSs). One RTS is set on the control point, and another is set on the undetermined point. All devices are connected to the control terminal through a wireless network, so that the two RTSs can perform synchronous tracking measurements towards the same 360° prism mounted on the UAV. With an algorithm developed based on the theory of Massive Moving Control Points for Free-stationing (MMCPF), high-accuracy position and orientation can be determined in a one-stop mode within several minutes. Results of the simulation experiment and the field experiment validated the feasibility of our system, showing a positioning accuracy of millimetre level and orientation accuracy of angular-second level. The newly proposed methodology can be applied for limited direct sight conditions and poor GNSS observation environments, especially for under-construction civil engineerings, such as high-rise buildings, dams, railways, and bridges. [ABSTRACT FROM AUTHOR]

Abstract: The Robotic Theodolite or Robotic Total Station (RTS) is a new generation geodetic instrument that can automatically record the changing coordinates of a moving target (reflector). RTS was so far used for monitoring of static and very slow displacements. This limitation was imposed by some characteristics of these instruments (real sampling rate <2 Hz and non-constant, noisy results in high frequency sampling, etc.). A study of a new generation of RTS based on: (1) systematic experiments using an apparatus producing oscillations of known, computer-determined characteristics (frequency and amplitude of oscillation) which were compared with those recorded by the RTS; (2) upgrading of the instrument’s built-in software to display measurements with a 0.01 s resolution; and (3) spectral analysis of the obtained non-equidistant data with a least-squares based software without prior interpolations, permitted us to show that the range of application of RTS may be safely extended to higher frequency oscillations. In particular, it was shown that: (1) the maximum real sampling rate of RTS is 6–7 Hz, but since sampling rate is variable, aliasing-free results can be obtained above the Nyquist frequency. (2) The potential to record oscillations depends on the maximum angular velocity of the instrument and on the maximum velocity of the moving target; for velocities up to about 10 cm/s in field studies, results are very precise. On the contrary, for targets moving with maximum velocities > 15 cm/s, some displacements cycles are not well-defined or are lost, and hence, the accuracy of the oscillation amplitude and frequency are lower. (3) RTS can be used to measure small (on the order of a few mm) amplitudes of oscillation, and to some degree of frequencies of oscillation of various relatively stiff engineering structures (modal frequencies > 1 Hz, up to 3–4 Hz). This potential is demonstrated on the basis of several field examples, including the monitoring of two bridges with dominant modal frequencies > 1.5 Hz. Obviously, these limits reflect the most unfavorable cases of application of RTS, and higher period/larger amplitude oscillations or other deflections can be successfully measured if the main requirement for this type of instrument is satisfied: an unobstructed view of a reflector at a maximum distance of a few hundred meters from an RTS set on stable ground. [Copyright &y& Elsevier]

Geodetic measuring methods are widely used in the course of various geotechnical works. The main purpose is usually related to the location in space, geometrical dimensions, settlements, deflections, and other forms of displacements and their consequences. This study focuses on the application of selected surveying methods in static load tests (SLTs) of foundation piles. Basic aspects of the SLT are presented in the introductory section, together with the explanation of the authors' motivation behind the novel (but already sufficiently tested) application of remote methods introduced to confirm, through inverse analysis, the load applied to the pile head under testing at every stage of its loading. Materials and methods are described in the second section in order to provide basic information on the test site and principles of the SLT method applied. The case study shows the methodology of displacement control in the particular test, which is described in light of a presented review of geodetic techniques for displacement control, especially terrestrial laser scanning and robotic tacheometry. The geotechnical testing procedure, which is of secondary importance for the current study, is also introduced in order to emphasize the versatility of the proposed method. Special attention is paid to inverse analysis (controlling of the pile loading force on the basis of measured deflections, and static calculations by means of standard structural analysis and the finite element method (FEM)) as a tool to raise the credibility of the obtained SLT results. The present case study from just one SLT, instrumented with various geodetic instrumentation, shows the results of a real-world dimensions test. The obtained variability of the loading force within a range of 15% (depending on real beam stiffness) proves good prospects for the application of the proposed idea in practice. The results are discussed mainly in light of the previous authors' experience with the application of remote techniques for reliable displacement control. As only a few references could be found (mainly by private communication), both the prospects for new developments using faster and more accurate instruments as well as the need for the validation of these findings on a larger number of SLTs (with a very precise definition of beam stiffness) are underlined in the final remarks. [ABSTRACT FROM AUTHOR]

Marble quarries are quite dangerous environments in which rock falls may occur. As many workers operate in these sites, it is necessary to deal with the matter of safety at work, checking and monitoring the stability conditions of the rock mass. In this paper, some results of an innovative analysis method are shown. It is based on the combination of Distributed Optical Fiber Sensors (DOFS), digital photogrammetry through Unmanned Aerial Vehicle (UAV), topographic, and geotechnical monitoring systems. Although DOFS are currently widely used for studying infrastructures, buildings and landslides, their use in rock marble quarries represents an element of peculiarity. The complex morphologies and the intense temperature range that characterize this environment make this application original. The selected test site is the Lorano open pit which is located in the Apuan Alps (Italy); here, a monitoring system consisting of extensometers, crackmeters, clinometers and a Robotic Total Station has been operating since 2012. From DOFS measurements, strain and temperature values were obtained and validated with displacement data from topographic and geotechnical instruments. These results may provide useful fundamental indications about the rock mass stability for the safety at work and the long-term planning of mining activities. [ABSTRACT FROM AUTHOR]

• Robotic total stations (RTSs) are applied to subway tunnel displacement monitoring. • An automatic subway tunnel displacement monitoring system is developed. • The mathematical models for both short and long monitoring zone are derived and tested. Real-time displacement monitoring is important for ensuring the safety of subway tunnel structures when construction activities are carried out near them. Owing to the special environmental characteristics of tunnels, many displacement monitoring techniques are either inapplicable to subway tunnel structures or have limitations in terms of the accuracy and automation of monitoring. Therefore, this article focuses on the automatic monitoring of subway tunnel displacement using robotic total stations. Using prisms as reflectors, the robotic total stations can perform highly accurate displacement monitoring by measuring angles and distances in a non-contact manner. A mathematical model for displacement monitoring with one total station in a short monitoring zone is developed, and a model for monitoring a long tunnel zone with multiple total stations is derived to guarantee the accuracy of monitoring. An automatic displacement monitoring system with robotic total stations is built, where the data acquisition and data management of the system are detailed through its hardware composition and software functions, respectively. An experiment on a tunnel showed the available monitoring range of a single robotic total station, and the accuracy of monitoring the long zone with multiple robotic total stations was verified. The application of the monitoring system to the Guangzhou Metro Line 2 confirmed its robustness. [ABSTRACT FROM AUTHOR]

Recent developments in localisation systems for autonomous robotic technology have been a driving factor in the deployment of robots in a wide variety of environments. Estimating sensor measurement noise is an essential factor when producing uncertainty models for state-of-the-art robotic positioning systems. In this paper, a surveying grade optical instrument in the form of a Trimble S7 Robotic Total Station is utilised to dynamically characterise the error of positioning sensors of a ground based unmanned robot. The error characteristics are used as inputs into the construction of a Localisation Extended Kalman Filter which fuses Pozyx Ultra-wideband range measurements with odometry to obtain an optimal position estimation, all whilst using the path generated from the remote tracking feature of the Robotic Total Station as a ground truth metric. Experiments show that the proposed method yields an improved positional estimation compared to the Pozyx systems’ native firmware algorithm as well as producing a smoother trajectory. [ABSTRACT FROM AUTHOR]