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Georeferencing of Multi-Channel GPR—Accuracy and Efficiency of Mapping of Underground Utility Networks
Remote Sensing
Abstract and Figures
Due to the capabilities of non-destructive testing of inaccessible objects, GPR (Ground Penetrating Radar) is used in geology, archeology, forensics and increasingly also in engineering tasks. The wide range of applications of the GPR method has been provided by the use of advanced technological solutions by equipment manufacturers, including multi-channel units. The acquisition of data along several profiles simultaneously allows time to be saved and quasi-continuous information to be collected about the subsurface situation. One of the most important aspects of data acquisition systems, including GPR, is the appropriate methodology and accuracy of the geoposition. This publication aims to discuss the results of GPR measurements carried out using the multi-channel Leica Stream C GPR (IDS GeoRadar Srl, Pisa, Italy). The significant results of the test measurement were presented the idea of which was to determine the achievable accuracy depending on the georeferencing method using a GNSS (Global Navigation Satellite System) receiver, also supported by time synchronization PPS (Pulse Per Second) and a total station. Methodology optimization was also an important aspect of the discussed issue, i.e., the effect of dynamic changes in motion trajectory on the positioning accuracy of echograms and their vectorization products was also examined. The standard algorithms developed for the dedicated software were used for post-processing of the coordinates and filtration of echograms, while the vectorization was done manually. The obtained results provided the basis for the confrontation of the material collected in urban conditions with the available cartographic data in terms of the possibility of verifying the actual location of underground utilities. The urban character of the area limited the possibility of the movement of Leica Stream C due to the large size of the instrument, however, it created the opportunity for additional analyses, including the accuracy of different location variants around high-rise buildings or the agreement of the amplitude distribution at the intersection of perpendicular profiles.
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... For example, MIRA, a 3D GPR array in Mala, Sweden, used the TDM method, which provided a standard system of 400 MHz antenna array, even with 200 MHz or 1.3 GHz antenna arrays available for selection [3]. The Stream series 3D GPR array developed by IDS in Italy also used the TDM method, and both the stream X system and stream C system were only equipped with a 200 MHz single band antenna array or a 600MHz single band antenna array [4][5][6]. The GeoScope 3D GPR system developed by the Norwegian 3D-Radar company, and included an antenna array that can step at frequencies ranging from 200 MHz to 3 GHz, as well as collect and store data in a frequency domain [7][8][9]. ...
... MHz or 1.3 GHz antenna arrays available for selection [3]. The Stream series 3D GPR array developed by IDS in Italy also used the TDM method, and both the stream X system and stream C system were only equipped with a 200 MHz single band antenna array or a 600MHz single band antenna array [4][5][6]. The GeoScope 3D GPR system developed by the Norwegian 3D-Radar company, and included an antenna array that can step at frequencies ranging from 200 MHz to 3 GHz, as well as collect and store data in a frequency domain [7][8][9]. ...
This paper describes the development of a new 3D ground-penetrating radar (GPR) acquisition and control technology for road underground diseases with dual-band antenna arrays. The 3D GPR system can be mounted on a vehicle-loading device and used by vehicles to detect road underground diseases at regular speeds. Compared with existing 3D GPR systems, this new type of 3D GPR has the following design features: it has dual-band antenna arrays, including a 16-channel 400 MHz antenna array and an 8-channel 200 MHz antenna array, which not only improves the detection efficiency, but also effectively balances the detection depth and detection resolution. A novel antenna switching method for time division step multiplexing (TDSM) is realized via field programmable gate array (FPGA), which not only avoids the crosstalk of antenna echo signals of different frequencies, but also ensures the interval of the same antenna working time. By combining the advantages of the FPGA and micro-control unit (MCU), and utilizing the high-speed transmission of the network port, the high-speed real-time transmission of the 3D GPR echo data is achieved. Finally, the integration of all software and hardware verified the correctness of the system, with good results.
... GPR has been commonly chosen to delineate the shallow geometry of subsurface materials or buried objects in a nondestructive and cost-effective manner. This technology has been widely applied in geology investigations [13][14][15][16], cultural heritage protection [9,[17][18][19], urban infrastructure detection [20][21][22][23], water dynamics investigation [24], etc. Owing to the relative electrical property contrasts in the different media, the shallow geometry of subsurface materials or buried objects was revealed on a gray or color two-dimensional (2D) GPR profile. Although the TLS is capable of recording the detailed 3D geometric information of real-world objects or environments, it is challenging to characterize the shallow geometry of subsurface materials with nonintrusive intervention. ...
Integrated TLS and GPR data can provide multisensor and multiscale spatial data for the comprehensive identification and analysis of surficial and subsurface information, but a reliable systematic methodology associated with data integration of TLS and GPR is still scarce. The aim of this research is to develop a methodology for the data integration of TLS and GPR for detailed, three-dimensional (3D) virtual reconstruction. GPR data and high-precision geographical coordinates at the centimeter level were simultaneously gathered using the GPR system and the Global Navigation Satellite System (GNSS) signal receiver. A time synchronization algorithm was proposed to combine each trace of the GPR data with its position information. In view of the improved propagation model of electromagnetic waves, the GPR data were transformed into dense point clouds in the geodetic coordinate system. Finally, the TLS-based and GPR-derived point clouds were merged into a single point cloud dataset using coordinate transformation. In addition, TLS and GPR (250 MHz and 500 MHz antenna) surveys were conducted in the Litang fault to assess the feasibility and overall accuracy of the proposed methodology. The 3D realistic surface and subsurface geometry of the fault scarp were displayed using the integration data of TLS and GPR. A total of 40 common points between the TLS-based and GPR-derived point clouds were implemented to assess the data fusion accuracy. The difference values in the x and y directions were relatively stable within 2 cm, while the difference values in the z direction had an abrupt fluctuation and the maximum values could be up to 5 cm. The standard deviations (STD) of the common points between the TLS-based and GPR-derived point clouds were 0.9 cm, 0.8 cm, and 2.9 cm. Based on the difference values and the STD in the x, y, and z directions, the field experimental results demonstrate that the GPR-derived point clouds exhibit good consistency with the TLS-based point clouds. Furthermore, this study offers a good future prospect for the integration method of TLS and GPR for comprehensive interpretation and analysis of the surficial and subsurface information in many fields, such as archaeology, urban infrastructure detection, geological investigation, and other fields.
... At surface mining sites, modern ground-penetrating radars are also smart sensors that control the movement of rock mass particles in the submillimeter range. In particular, the connection of the data from receivers of the Global Navigation Satellite System and the synchronizer pulse per second [50] gives higher accuracy. ...
The problem of sustainability of energy production in the context of the expansion of renewable energy cannot be solved without a deep technological modernization of the fossil fuels extraction in line with Industry 4.0. Along with this, the expected transition to the human-centric Industry 5.0 raises the question for researchers: what core technologies of the Mining 4.0 platform will determine its transformation into Mining 5.0 in order to meet the imperative of sustainable development and the dominance of green energy. This review presents a multifaceted overview of Mining 4.0 core technologies, derived from Industry 4.0, such as smart sensors, neural networks, Big Data analytics, Internet of Things, digital twins and artificial intelligence, that form cyber-physical systems for high-performance and complete extraction of fossil energy sources. The review of works in the field of transition to Industry 5.0 is associated with Mining 5.0 core technologies—Cloud Mining, post-mining, biochemical extraction of minerals and production of green hydrogen fuel from fossil hydrocarbons, which is expected after 2050. A conclusion is made about the need for a deep analysis of harmonizing the possibilities for the innovative development of fossil fuel sources and renewable energy for sustainable energy production in the upcoming decades.
... Great prospects in this segment of the Surface Mining 4.0 technological platform include the connection of mining geo-scanners for the local positioning of fragments of rock arrays that are subject to excavation (collapse of blasted rocks, quaternary deposits) with GNSS (Global Navigation Satellite System) receivers, and a PPS (Pulse Per Second) time synchronizer. The resulting modeling accuracy was sufficient to exclude a person from the process of managing mining equipment [60]. Improving the accuracy of geo-scanning in surface mining was made possible by modeling the spatial distribution of the bands of the interferogram created by a Single Look Complex SAR using the EMDD-PSI (External Model-based Deformation Decomposition of Persistent Scatterer Interferometry) method. ...
The expansion of end-to-end Industry 4.0 technologies in various industries has caused a technological shock in the mineral resource sector, wherein itsdigital maturity is lower than in the manufacturing sector. As a result of the shock, the productivity and profitability of raw materials extraction has begun to lag behind the industries of its deep processing, which, in the conditions of volatile raw materials markets, can provoke sectoral crises. The diffusion of Industry 4.0 technologies in the mining sector (Mining 4.0) can prevent a technological shock if they are implemented in all segments, including quarrying (Surface Mining 4.0). The Surface Mining 4.0 technological platform would connect the advanced achievements of the Fourth Industrial Revolution (end-to-end digital artificial intelligence technologies, cyber-physical systems and unmanned production with traditional geotechnology) without canceling them, but instead bringing them to a new level of productivity, resource consumption, and environmental friendliness. In the future, the development of Surface Mining 4.0 will provide a response to the technological shock associated with the acceleration of the digital modernization of the mining sector and the increase in labor productivity, which are reducing the operating costs of raw materials extraction. In this regard, the given review is an attempt to analyze the surface mining digital transformation over the course of the diffusion of Industry 4.0 technologies covered in scientific publications. The authors tried to show the core and frontiers of Surface Mining 4.0 development to determine the production, economic, and social effect of replacing humans with digital and cyber-physical systems in the processes of mineral extraction. Particular attention was paid to the review of research on the role of Surface Mining 4.0 in achieving sustainable development goals.
... • Belt 4.0-underground and surface mine conveyor condition and loading control system based on artificial intelligence, which makes it possible to eliminate sudden stops due to breakdowns completely [73]; • Air flow visualization system connected to mine ventilation equipment to radically increase the accuracy of modeling [74]; • LiDAR (light identification detection and ranging) systems integrated with GPS (global positioning system) when creating a 3D cloud to predict sudden movements of rock mass [75]; • Land area subsidence prediction in clusters with high concentration of underground mining using differential interferometric synthetic aperture radar [76]; • Integration of InSAR (interferometric synthetic aperture radar) and LiDAR data with analysis of photographs made by aerial drones to predict soil deformations [77]; • Remote creation of predictive maps of surface subsidence and collapse over working mine longwalls using differential radar interferometry with an accuracy of 4 cm [78], using the GrabCut method to create high-precision scalable visual attention modelsthe first step towards full robotization of deserted mines [79]; • Integration of data from geoscanners with information from global navigation satellite system devices to achieve the highest accuracy of 3D modeling of underground mine workings, sufficient for unmanned control of processes in underground mines (with time synchronization using pulse per second) [80]. At the same time, groundpenetrating radars are also developing in the direction of increasing the accuracy of determining the deformation of mine workings, already in the submillimeter range. ...
The sustainable provision of mankind with energy and mineral raw materials is associated with an increase not only in industrial but also in the ecological and economic development of the raw material sector. Expanding demand for energy, metals, building and chemical raw materials on the one hand, and the deterioration of the living environment along with a growth of raw materials extraction on the other, put the human-centric development of mining at the forefront. This forms a transition trend from Mining 4.0 technologies such as artificial intelligence, big data, smart sensors and robots, machine vision, etc., to Mining 5.0, presented with collaborative robots and deserted enterprises, bioextraction of useful minerals, postmining, and revitalization of mining areas. This “bridge” is formed by the technological convergence of information, cognitive, and biochemical technologies with traditional geotechnology, which should radically change the role of the resource sector in the economy and society of the 21st century. The transition from Mining 3.0 to 4.0 cannot be considered complete. However, at the same time, the foundation is already being laid for the transition to Mining 5.0, inspired, on the one hand, by an unprecedented gain in productivity, labor safety, and predictability of commodity markets, on the other hand, by the upcoming onset of Industry 5.0. This review provides a multilateral observation of the conditions, processes, and features of the current transition to Mining 4.0 and the upcoming transformation on the Mining 5.0 platform, highlighting its core and prospects for replacing humans with collaborated robots and artificial intelligence. In addition, the main limitations of the transition to Mining 5.0 are discussed, the overcoming of which is associated with the development of green mining and ESG (environment, social, and governance) investment.
... GPR may also be used to detect the invisible and sophisticated network of underground utilities such as water supply pipes, stormwater drainage, sewers, gas pipes, power cables, communications cables, and traffic lights cables [81,82]. The mapping and scanning of underground utilities are one of the most difficult GPR activities of all civil engineering applications. ...
Ground-penetrating radar (GPR) is an established technology with a wide range of applications for civil engineering, geological research, archaeological studies, and hydrological practices. In this regard, this study applies bibliometric and scientometric assessment to provide a systematic review of the literature on GPR-related research. This study reports the publication trends, sources of publications and subject categories, cooperation of countries, productivity of authors, citations of publications, and clusters of keywords in GPR-related research. The Science Citation Index Expanded (SCI-EXPANDED) and the Social Sciences Citation Index (SSCI), which can be accessed through the Web of Science Core Collection, are used as references. The findings report that the number of publications is 6880 between 2001 and 2021. The number of annual publications has increased significantly, from 139 in 2001 to 576 in 2021. The studies are published in 894 journals, and the annual number of active journals increased from 68 in 2001 to 215 in 2021. Throughout the study, the number of subject categories involved in GPR-related research fluctuated, ranging from 38 in 2001 to 68 in 2021. The research studies originated from 118 countries on 6 continents, where the United States and the People’s Republic of China led the research articles. The top five most common keywords are ground-penetrating radar, non-destructive testing, geophysics, electrical resistivity tomography, and radar. After investigating the clusters of keywords, it is determined that civil engineering, geological research, archaeological studies, and hydrological practices are the four main research fields incorporating GPR utilization. This study offers academics and practitioners an in-depth review of the latest research in GPR research as well as a multidisciplinary reference for future studies.
... The use of underground georadar as smart local positioning sensors for monitoring mountain ranges can be more accurate when paired with Global Navigation Satellite System (GNSS) receivers and a Pulse Per Second (PPS) time synchronizer. The result is unsurpassed modeling accuracy, which is necessary for the safe placement of surface objects in the zone of intensive underground mining [60]. ...
Ensuring a sustainable supply for humankind with mineral raw materials and preventing fuel and energy crises, minimizing human-made accidents and the negative impact of industry on the environment, the inflow of funds and innovations into the mining sector should be expanding in time and space. To do this, new mining platforms should have not only innovative and technological, but also social-and-economic coverage of the latest competencies, which Mining 4.0 fully corresponds to. The achievements of the Fourth Industrial Revolution, embodied in “end-to-end” digital and convergent technologies, are able to ensure the stable development of the mineral resource sector in the face of fluctuations in raw material demand and the profitability of mining enterprises, strengthening environmental safety legislation. Mining 4.0 is also a response to the technological shocks associated with the accelerated digital modernization of the manufacturing and infrastructure industries. This article attempts to give a multilateral overview of mining industries transformation in the course of the diffusion of Industry 4.0 technologies, to highlight the core and frontiers of Mining 4.0 expansion, to show the opportunities and threats of replacing physical systems and humans in mining with cyber-physical systems. Further, the technological, economic and social horizons of the transformation of Mining 4.0 into Mining 5.0 with specific threats of total digitalization are discussed.
This paper describes in detail the applicability of the developed ground-penetrating radar (GPR) model with a kinematic GPR and self-tracking (robotic) terrestrial positioning system (TPS) surveying setup (GPR-TPS model) for the acquisition, processing and visualisation of underground utility infrastructure (UUI) in a real urban environment. The integration of GPR with TPS can significantly improve the accuracy of UUI positioning in a real urban environment by means of efficient control of GPR trajectories. Two areas in the urban part of Celje in Slovenia were chosen. The accuracy of the kinematic GPR-TPS model was analysed by comparing the three-dimensional (3D) position of UUI given as reference values (true 3D position) from the officially consolidated cadastre of utility infrastructure in the Republic of Slovenia and those obtained by the GPR-TPS method. To determine the reference 3D position of the GPR antenna and UUI, the same positional and height geodetic network was used. Small unmanned aerial vehicles (UAV) were used for recording to provide a better spatial display of the results of UUI obtained with the GPR-TPS method. As demonstrated by the results, the kinematic GPR-TPS model for data acquisition can achieve an accuracy of fewer than 15 centimetres in a real urban environment.
Intensified investment processes in construction have resulted in increased interest in the methods of efficient detection, verification and location of underground utility networks. In addition to the well-known pipe and cable locating equipment, which has increased its efficiency and reliability through the development of technologies, GPRs are becoming more and more popular.
This publication presents the results of the experimental research carried out with the use of GPRs manufactured by two different companies as well as the results of the verification of underground utilities in real conditions. The GPRs have worked in the mode of the real-time location of their own position using the GNSS system or robotic total stations.
The GPR (Ground Penetrating Radar) surveys performed on a test field, consisting of 9 pipes with a known position, were aimed at assessing the accuracy of their identification on echograms. The utility line location errors were determined using three different combinations between the GPR and the locating instrument. It allowed the evaluation of the possibility of using these solutions for detection, verification and location of underground utility networks in the light of the Polish legal regulations and the British specification PAS 128.
The verification in real conditions was carried out in a typical urban space, characterised by an intense occurrence of underground utilities, that is, sewage systems, gas pipelines and power cables. It was based on the GESUT database captured from the county geodetic and cartographic documentation centre. The results of the visual analysis of the materials captured with the help of two measurement systems were described in detail, however, the verification was carried out only for one set of data. The authors have presented the procedure of processing echograms and detecting the location of pipeline axes based on their vectorisation. The authors of this research paper have performed a numerical analysis of the compliance of the profiles of utility lines with the information from the base map for two variants of the GPR data integration with the coordinates. The authors of this research paper have also presented an alternative concept of capturing the profile of a utility line in the field based on the processing of GPR data in 3D – the so-called C-scan. The conclusions summarise the possible factors affecting the surveying results and the methods of eliminating sources of errors, both for the GPR and geodetic data.
This paper describes in detail the development of a ground-penetrating radar (GPR) model for the acquisition, processing and visualisation of underground utility infrastructure (UUI) in a controlled environment. The initiative was to simulate a subsurface urban environment through the construction of regional road, local road and pedestrian pavement in real urban field/testing pools (RUTPs). The RUTPs represented a controlled environment in which the most commonly used utilities were installed. The accuracy of the proposed kinematic GPR-TPS (terrestrial positioning system) model was analysed using all the available data about the materials, whilst taking into account the thickness of the pavement as well as the materials, dimensions and 3D position of the UUI as given reference values. To determine the reference 3D position of the UUI, a terrestrial geodetic surveying method based on the established positional and height geodetic network was used. In the first phase of the model, the geodetic network was used as a starting point for determining the 3D position of the GPR antenna with the efficient kinematic GPR surveying setup using a GPR and self-tracking (robotic) TPS. In the second phase, GPR-TPS system latency was quantified by matching radargram pairs with a set of fidelity measures based on a correlation coefficient and mean squared error. This was followed by the most important phase, where, by combining sets of “standard” processing routines of GPR signals with the support of advanced algorithms for signal processing, UUI were interpreted and visualised semi-automatically. As demonstrated by the results, the proposed GPR model with a kinematic GPR-TPS surveying setup for data acquisition is capable of achieving an accuracy of less than ten centimetres
Ground-penetrating radar (GPR) is widely used for detecting buried underground object. Deep learning technique is recently being adopted into this field thanks to its powerful image classification capacity. However, it uses only GPR B-scan images, although multichannel GPR device can provide more informative three-dimensional (3D) data for underground object. In this study, a novel deep learning-based underground object classification method is proposed by using two-dimensional (2D) grid image which consists of several B-scan and C-scan images. Spatial information of an underground object can be well represented in the 2D grid image. The 2D grid images are then used to train deep convolutional neural networks. The proposed method is experimentally validated by field data collected from urban roads in Seoul, South Korea. The performance is also compared to a conventional method which uses only B-scan images. The proposed method successfully classifies cavity, pipe, manhole and subsoils background having very small false-positive errors.
The demand for mapping the buried cables is increasing dramatically with the rapid expansion of urban area, but there are few specific procedures and approaches to map underground cables without disturbing the normal electricity supply. In this letter, a cable-mapping approach based on the ground-penetrating radar (GPR) is proposed, which consists of two parts. First, the parallel scan lines are established along which the GPR is moved to obtain the B-scan images; the hyperbolic shapes on these obtained images are identified and fitted; and the locations and depths of the detected sample points of the buried cables could be derived from these hyperbolas. Then, due to different terrain and surrounding obstacles, as well as the use of pipe-jacking technology,
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the underground cables may not be straight. The detected points are interpolated by a three-dimensional spline interpolation algorithm to obtain a smooth 3-D curve with location and depth information. Compared with the 2-D model, the 3-D curve could visualize the direction of buried cables more intuitively. Also, in comparison with other interpolation algorithms, the error caused by the proposed interpolation is minimized on the chosen data sets. Experiments on real-world data sets are conducted, and the obtained results demonstrate the effectiveness of the proposed model.
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Pipe-jacking is a trenchless technology for buried utilities [1] .
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This chapter offers an overview on the use of ground-penetrating radar (GPR) for the nondestructive testing (NDT) of transport infrastructures. After a general introduction to the topic of the chapter (Section 1), particular attention is devoted to the use of GPR for the inspection of roads, highways, and airport runways (Section 2); railways (Section 3); bridges (Section 4); and tunnels (Section 5). For each application, the possible objectives of a GPR survey are listed; several practical recommendations about the methodology of application are given; complementary noninvasive techniques that can be combined with GPR are suggested; new or recent examples are presented; and finally, the relevant research activities carried out within COST Action TU1208 Civil Engineering Applications of Ground Penetrating Radar are discussed. Throughout the chapter, the importance of electromagnetic modeling as a useful and effective tool for GPR data interpretation is highlighted. In Section 6, this subject is dealt more in detail: Recommendations are provided, for a correct implementation and execution of electromagnetic models of transport infrastructures by using the finite-difference time-domain technique; the main features of two software tools developed within COST Action TU1208 are resumed; and a new example of application is presented, where a model of a medieval bridge is built and executed, for an advanced interpretation of experimental data collected over it. Finally, in Section 7, conclusions are drawn, and final remarks are given. The chapter includes a rich bibliography, with numerous relevant and recent references for further readings.
Blind test/experiment is widely adopted in various scientific disciplines like medicine drug testing/clinical trials/psychology, but not popular in nondestructive testing and evaluation (NDTE) nor near-surface geophysics (NSG). This paper introduces a blind test of nondestructive underground void detection in highway/pavement using ground penetrating radar (GPR). Purpose of which is to help the Highways Department (HyD) of the Hong Kong Government to evaluate the feasibility of large-scale and nationwide application, and examine the ability of appropriate service providers to carry out such works. In the past failure case of such NDTE/NSG based on lowest bid price, it is not easy to know which part(s) in SWIMS (S – service provider, i.e. people; W – work procedure; I – instrumentation; M – materials in the complex underground; S – specifications by client) fails, and how it/they fail(s). This work attempts to carry out the blind test by burying fit balls (as voids) under a site with reinforced concrete road and paving block by PolyU team A. The blind test about the void centroid, spread and cover depth was then carried out by PolyU team B without prior information given. Then with this baseline, a marking scheme, acceptance criteria and passing mark were set to test six local commercial service providers, determine their scores and evaluate the performance. A pass is a prerequisite of the award of a service contract of similar nature. In this first attempt of the blind test, results were not satisfactory and it is concluded that ‘S–service provider’ and ‘W–work procedure’ amongst SWIMS contributed to most part of the unsatisfactory performance.+