Underground Positioning Research Articles

Research on Underground Positioning Technology for Buried PE Pipes Based on Acoustic Waveguide Resonance

Research on Underground Positioning Technology for Buried PE Pipes Based on Acoustic Waveguide Resonance

An optimization strategy for anchor point placement for underground coal mine area positioning

Coal mine underground positioning technology plays an important role in safe mining, personnel monitoring and dispatching, and post-disaster rescue. Recently, there has been an increasing interest in indoor localization due to the demand for location-based services. Diverse techniques have been described in the literature to improve indoor localization services, but their accuracy is significantly affected by the number and location of the anchors, which act as a reference point for localizing tags in a given space. This work describes APOTSA, a novel approach for discovering a high-quality placement of anchors to improve the accuracy of area-based indoor localization systems while requiring a shorter execution time than existing approaches. The proposed algorithm is based on Tabu search and optimizes the localization accuracy by minimizing the expected residence area, which indicates a geographical area containing the tag. APOTSA's effectiveness with respect to solution quality and time of execution is shown by evaluating different scenarios involving up to five anchors. Moreover, a simple yet effective discretization approach is introduced to speed up the calculations, and the trade-off between the running time and solution quality of our algorithm can be controlled by a parameter. Our results indicate that the expected residence area and the time of execution can be reduced by up to 9.5 % and 99 %compared to the state-of-the-art local search anchors placement (LSAP) algorithm, respectively.

A Review on Non-RF Underground Positioning Techniques for Mining Applications

A Review on Non-RF Underground Positioning Techniques for Mining Applications

Research on Location Estimation for Coal Tunnel Vehicle Based on Ultra-Wide Band Equipment

Because the road surfaces of the underground roadways in coal mines are slippery, uneven, with dust and water mist, and the noise and light illumination effects are significant, global positioning system (GPS) signals cannot be received, which seriously affects the ability of the odometer, optical camera and ultrasonic camera to collect data. Therefore, the underground positioning of coal mines is a difficult issue that restricts the intellectualization of underground transportation, especially for automatic robots and automatic driving vehicles. Ultra-wide band (UWB) positioning technology has low power consumption, high performance and good positioning effects in non-visual environments. It is widely used in coal mine underground equipment positioning and information transmission. In view of the above problems, this research uses the WLR-5A mining unmanned wheeled chassis experimental platform; uses two UWB receivers to infer the position and yaw information of the vehicle in the underground roadway through the method of differential mapping; and tests the vehicle on the double shift line and quarter turn line in the GAZEBO simulation environment and on the ground simulation roadway to simulate the vehicle meeting conditions and quarter turning conditions in the underground roadway. The positioning ability of the method in these two cases is tested. The simulation and test results show that the vehicle position and attitude information deduced by two UWB receivers through the differential mapping method can basically meet the requirements of underground environments when the vehicle is traveling at low speeds.

Research on braking energy recovery technology of electric vehicle in underground coal mine based on road condition recognition technology

Electric explosion-proof trackless rubber-wheeled vehicles in coal mines usually use braking energy recovery technology to improve cruising range. In order to improve the efficiency of vehicle braking energy recovery and improve vehicle braking safety performance, this paper proposes a braking energy recovery control strategy for electric vehicles in coal mines based on road condition recognition. This strategy is based on the coal mine underground positioning technology, and adopts different braking energy recovery control strategies for different road conditions, while improving the braking energy recovery ratio of the vehicle, it ensures a good feeling of the brake pedal and ensures the safety performance of the vehicle braking. Finally, the feasibility of the control strategy is verified by simulation.

An Acoustic 3-D Positioning System for Robots Operating Underground

Underground robots are potentially helpful in many application domains, including geotechnical engineering, agriculture, and archaeology. One of the critical challenges in developing underground robotics is the accurate estimation of the positions of the robots. Acoustic-based positioning systems have been explored for developing an underground 3-D positioning system. However, the positioning range is limited due to attenuation in the medium. This letter proposes an underground positioning system that utilizes a novel and easy-to-implement electronic approach for measuring the acoustic propagation times between multiple transmitters and a receiver. We demonstrate a prototype using four transmitters at the surface and a single buried acoustic sensor as a proof of concept. The times of arrival for signals emitted by the different sources are measured by correlating the transmitted and received signals. The distances between the multiple transmitters and a receiver are estimated, and a trilinearization algorithm is used to estimate the position of the buried sensor in 3-D with respect to reference coordinates. The system is tested in a soil tank. The experimental results show that the proposed system is able to estimate the 3-D position of buried sensors with an error of less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 2.5 cm within a measurement field of size 50 × 50 × 35 cm in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> , <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Y</i> , and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z</i> (width × length × depth). The proposed electronic synchronization approach allows increasing the positioning range of the system by increasing the number of transmitters at the surface. This paves the way for the development of a positioning system for robots operating underground.

Hybrid boundary full-wave-equation depth migration based on dual-sensor acquisition system and its application

The dual-sensor acquisition system arranges two-layer geophones on the surface and their corresponding underground positions, and receives the wavefield simultaneously for accurately solving the full-wave equation. Theoretically, using the two-layer wavefield data obtained by the acquisition system, the two-way wavefield extrapolation can be realized in the depth domain without approximate processing of the wave equation, and the migration algorithm based on the dual-sensor framework has better amplitude preservation. However, limited to the acquisition expenses and difficulties, the spacing of the two-layer sensors is hard to match the actual migration step in real data acquisition. Meanwhile, poor geophone coupling and nonstandard data processing procedures would also lead to unsatisfied imaging results. Thus, some schemes suitable to dual-sensor data, including hybrid boundary wavefield extrapolation strategy, data processing, quality monitor, are proposed to handle these issues, using the delay time difference as a main analyzing object. The numerical simulation and actual data verify the feasibility and effectiveness of the proposed method.

3D Global Localization in the Underground Mine Environment Using Mobile LiDAR Mapping and Point Cloud Registration.

This study proposes a 3D global localization method that implements mobile LiDAR mapping and point cloud registration to recognize the locations of objects in an underground mine. An initial global point cloud map was built for an entire underground mine area using mobile LiDAR; a local LiDAR scan (local point cloud) was generated at the point where underground positioning was required. We calculated fast point feature histogram (FPFH) descriptors for the global and local point clouds to extract point features. The match areas between the global and the local point clouds were searched and aligned using random sample consensus (RANSAC) and iterative closest point (ICP) registration. The object’s location on the global coordinate system was measured using the LiDAR sensor trajectory. Field experiments were performed at the Gwan-in underground mine using three mobile LiDAR systems. The local point cloud dataset formed for the six areas of the underground mine precisely matched the global point cloud, with a low average error of approximately 0.13 m, regardless of the type of mobile LiDAR system used. In addition, the LiDAR senor trajectory was aligned on the global coordinate system to confirm the change in the dynamic object’s position over time.

Achieving Reliable Underground Positioning With Visible Light

Visible light technology shows great potential in the underground mine positioning today. Most visible light-based underground positioning technology deploy the receiver, such as photodiodes (PDs), on the mine tunnel ground and consider the miner’s lamp on the ceiling as the transmitter. This incurs the unreliable reception of visible light signals and the difficult implementation of VLP systems due to the complex underground mine environment, such as the receiver being obscured or trampled by objects (e.g., Minecarts and Ore). We present a reliable underground positioning algorithm with visible light considering the actual mine environment. The key innovation is that we design a novel reverse mechanism, i.e., utilizing the existing miner’s headlamp as the transmitter for broadcasting the specific light beacon representing the mine’s identity information, and the PDs deployed on the ceiling of the mine tunnel as the receiver for optical signal reception. We can infer the current locations of all miners using a series of base stations constructed by PDs. If some special mine environment limits the large-scale deployment of base stations and causes the positioning blind spots, the inertial navigation is combined to achieve all miners’ real-time positioning. We overcome some technical challenges for this new mechanism and the underground mine environment, such as optimal frequency selection, robust frequency identification, and accurate base station positioning. We conduct extensive experiments on our algorithm in a simulated mine tunnel, and the experimental results verify that our algorithm exhibits good performance.

Application of Improved Kalman Filter in Under-Ground Positioning System of Coal Mine

In order to improve the accuracy and anti-interference of underground environment positioning, a coal mine underground ultra wideband based positioning system is designed. Aiming at the problems of large accidental errors and poor robustness in traditional UWB positioning, the extended Kalman filter algorithm is added to improve the accuracy of the positioning system. Aiming at the problems of large accidental errors and poor robustness in traditional UWB positioning, the extended Kalman filter algorithm is added to improve the accuracy of the positioning system. The experimental results show that the Kalman filter can improve the positioning accuracy and reduce the system accidental error.

Application of Wireless Ad Hoc Network in Underground Voice Communication and Positioning

Application of Wireless Ad Hoc Network in Underground Voice Communication and Positioning

Numerical Modelling of the Behavior of Tunnel in Soft Surrounding Rock: A Case Study of Djebel El-Ouahch Tunnel, Algeria

The response of a massif to stresses generated by tunnel excavation depends essentially on the geological conditions, the geometry of the tunnel and its underground position. The major problem related to the construction of these structures is to ensure the stability of the whole tunnel-ground, by controlling the various deformation generated during the construction. In this context, the present paper examines the effect of these conditions on the behavior of tunnels and the surrounding soil. The study is applied to a real tunnel, in this case the tunnel of Djebel El Ouahch, Algeria was taken as a reference model. The research includes a parametric study to evaluate the effect of several parameters on the behavior of the tunnel and surrounding soil such as the tunnel anchoring depth, the tunnel-soil interface rate, and the shape of the tunnel cross section. The analysis is performed using the PLAXIS 3D TUNNEL calculation code with an elastoplastic Mohr–coulomb model for the soil behavior. The results show that the strongest and most stable position is the mid-deep tunnel with a circular section, with a non-slip interface between the tunnel and the ground. These outcomes can help to understand the effects of various influences parameters which control the stability of the tunnel in a soil with bad characteristics.

Gravity survey and modelling of the Nemocón salt mine, Colombia

ABSTRACTA gravity survey was conducted at a salt mine in Nemocón, Cundinamarca, Colombia, located in the axial part of the Eastern Cordillera of the northern Andes. This part of the Eastern Cordillera is characterized by successions of synclines and anticlines sometimes containing salt bodies at their core, and the mine is located at the top of one of these anticlines called the Nemocón anticline. As is typical for salt and other mines in Colombia, very little data on the internal structure and geology are publicly available. The purpose of our study is to show how gravity data and modelling can be used to infer near‐surface properties above the mine in the absence of other sources of information. Relative gravity measurements were made over an irregular grid of 107 stations and tied to the Instituto Geográfico Augustin Codazi national absolute gravity network. The total and residual Bouguer anomalies as well as the analytic signal were calculated over the area of the salt body. Using grid data, we first determine the main inversion parameters (e.g., depth weighting) and model resolution using a checkerboard model with the addition of random noise. Then, applying 3D inversion modelling to the residual Bouguer anomaly, we find that the positive and negative anomalies correspond to few zones of positive density contrasts and two main zones of negative density contrasts. Some of the positive anomalies are located above the fault trace putting in contact the Arenisca Dura formation with the Conejo formation containing the salt body. The negative anomalies are not well correlated with the underground position of the salt mine, but some influence of the low‐density ‘rute’ material, consisting of black clays with shaly claystone parts covering the salt body might be important. This study showcases how 3D inverse modelling can provide important information on the near‐surface structure of a salt mine.

Navigation and positioning technology in underground coal mines and tunnels: A review

SYNOPSIS To reduce the frequency of mining incidents and improve safety and production efficiency, it is important to develop technology for the autonomous positioning and navigation of mining equipment, without the assistance of satellite navigation signals. In this study we review the current technological environment for positioning and navigation underground and present several integrated navigation strategies. Existing underground positioning and navigation technology is described, and the performances of different methods based on this technology analysed and compared. The combination types and positioning effects of underground positioning and navigation strategies are discussed. Recent research directions for filtering methods and positioning estimation algorithms for underground positioning and navigation are reviewed. Finally, we summarize the future direction of underground positioning and navigation technology and related algorithms. Keywords: coal mining; underground positioning and navigation, integrated navigation strategy, inertial navigation, positioning algorithms.

From the streets to the mainstream: popularization of Turkish rap music

ABSTRACT Turkish rap music has dominated the scene since 2017. This transformation occurred very quickly. Turkish rap was pioneered by alienated Turkish immigrants in Germany. Initially, it served as a tool for self-expression and dissent from an underground position. Although political rap gained popularity for a short period during the Gezi protests, today’s rappers are turning into influencers rather than protestors and harming rap’s ability of social expression. This research focuses on Turkish rap music’s integration with the current capitalist industries by using the perspectives of both cultural studies and political economy through interviews with industry professionals and historical analysis.

Muometric positioning system (\u03bcPS) with cosmic muons as a new underwater and underground positioning technique

Thus far, underwater and underground positioning techniques have been limited to those using classical waves (sound waves, electromagnetic waves or their combination). However, the positioning accuracy is strongly affected by the conditions of media they propagate (temperature, salinity, density, elastic constants, opacity, etc.). In this work, we developed a precise and entirely new three-dimensional positioning technique with cosmic muons. This muonic technique is totally unaffected by the media condition and can be universally implemented anywhere on the globe without a signal transmitter. Results of our laboratory-based experiments and simulations showed that, for example, plate-tectonics-driven seafloor motion and magma-driven seamount deformation can be detected with the μPS.

Visible Light Communication and Augmented Reality for Underground Positioning System

Visible Light Communication (VLC) technology allows wireless data transmission piggybacked by illumination. Highly accurate and reliable systems based on VLC, as Indoor Positioning System (IPS) have been already developed by academics and specialized companies. Underground Positioning System (UPS) addressed here is embedded into the protection equipment, compulsory to be used underground, being therefore important to workers in potential dangerous spaces since fast data communication and real-time data interpretation is therefore possible. This paper presents the VLC technology implemented in mining underground specific environment for an accurate positioning and fast data communication for underground navigation with the main aim of developing a real time warning and alarming system based on Augmented Reality (AR) and Neural Networks (NNs) principles.

Sewer Deterioration Modeling: The Effect of Training a Random Forest Model on Logically Selected Data-groups

Breakdown of sewers can induce significantly damage to roads and buildings placed upon it. For this reason, timely maintenance of the sewer system is essential. However, due to the under-ground position of the sewers they are very expensive to monitor, as this is done by CCTV inspection. Therefore, it is important to choose the right sewers for inspection and several decision-support tools have been developed to help the operators to select which sewers to inspect. These decision support tools all contain a model which predicts the condition of the sewers, and recently several models have been proposed in order to increase the performance. The scope of this paper is to investigate the effect of training a Random Forest model on logically selected groups of data, as opposed to training of a joined model on the full data set. The selected data groups were based on expert knowledge: The first data groups were based on the sewer material (concrete, plastic, clay, reinforced with lining and other material). The concrete data set was then further sub-divided into wastewater types (sewage, rain and combined) whereas the plastic data set was sub-divided into road classes. The results showed that the model trained on the full data set performed better than the models trained on logically selected data-groups as it encounters the heterogeneity of the data set. Furthermore, this answers an important question raised by end users of the deterioration models.

A new method for absolute underground positioning based on transient electromagnetics

SUMMARY We present a procedure for localizing underground positions using a time-domain inductive electromagnetic (EM) method. The position to be localized is associated with an EM receiver placed inside the Earth. An EM field is generated by one or more transmitters located at known positions at the Earth’s surface. We then invert the EM field data for the receiver positions using a trust-region algorithm. For any given time regime and source–receiver geometry, the propagation of the electromagnetic fields is determined by the electrical conductivity distribution within the Earth. We show that it is sufficient to use a simple 1-D model to recover the receiver positions with reasonable accuracy. Generally, we demonstrate the robustness of the presented approach. Using confidence ellipses and confidence intervals we assess the accuracy of the recovered location data. The proposed method has been extensively tested against synthetic data obtained by numerical experiments. Furthermore, we have successfully carried out a location recovery using field data. The field data were recorded within a borehole in Alberta (Canada) at 101.4 m depth. The recovered location of the borehole receiver differs from the actual location by 0.70 m in the horizontal plane and by 0.82 m in depth.

A Method of FPGA-Based Extraction of High-Precision Time-Difference Information and Implementation of Its Hardware Circuit.

The positioning technology to find shallow underground vibration sources based on a wireless sensor network is receiving great interest in the field of underground position measurements. The slow peaking and strong multi-waveform aliasing typical of the underground vibration signal result in a low extraction accuracy of the time difference and a poor source-positioning accuracy. At the same time, the transmission of large amounts of sensor data and the host computer’s slow data processing speed make locating a source a slow process. To address the above problems, this paper proposes a method for high-precision time-difference measurements in near-field blasting and a method for its hardware implementation. First, based on the broadband that is typical of blast waves, the peak frequency of the P-wave was obtained in the time–frequency domain, taking advantage of the difference in the propagation speed of the P-wave, S-wave, and the surface wave. Second, the phase difference between two sensor nodes was found by means of a spectral decomposition and a correlation measurement. Third, the phase ambiguity was eliminated using the time interval of the first break and the dynamic characteristics of the sensors. Finally, following a top-down design idea, the hardware system was designed using Field Programmable Gate Array(FPGA). Verification, using both numerical simulations and experiments, suggested that compared with generalized cross-correlation-based time-difference measurement methods, the proposed method produced a higher time-difference resolution and accuracy. Compared with the traditional host computer post-position positioning method, the proposed method was significantly quicker. It can be seen that the proposed method provides a new solution for solving high-precision and quick source-location problems, and affords a technical means for developing high-speed, real-time source-location instruments.