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The auxiliary transportation system for coal mine is an essential system for transporting personnel, important materials, and equipment in coal mine enterprises. Realizing unmanned driving in coal mine is an inevitable requirement for improving transportation efficiency and ensuring transportation safety, and is also the only way to implement the national coal mine intelligent construction deployment. The mine unmanned driving relies on accurate and real-time environmental perception. By using onboard perception devices such as LiDAR and millimeter wave radar, as well as collaborative perception supported by the Internet of vehicles, the precise and detailed perception of local vehicles and even the entire mine is achieved. A systematic review is conducted on the research status of unmanned driving environment perception technology in mines. It is pointed out that the special environment of coal mine will lead to varying degrees of degradation in the performance of mine onboard perception devices. The advantages and disadvantages of various onboard perception devices are summarized. The key technologies of mine unmanned driving environment perception are elaborated in detail. The technologies include single-sensor obstacle recognition methods based on visible light images or laser point clouds, the classification of multi-sensor fusion perception, and multi-sensor fusion methods such as visible light images+laser point clouds, visible light images+millimeter wave point clouds, visible light images+laser point clouds+millimeter wave point clouds, 4D millimeter wave radar+other perception devices. The technologies include the implementation, data processing methods of intelligent networked collaborative perception, and their promoting effects on unmanned driving. The technologies also include methods for detecting and recognizing traffic signs in underground roadways, and methods for segmenting the driving area of underground trackless rubber wheeled vehicles and tracked locomotives in roadways. The development direction of unmanned driving environment perception technology in mines is pointed out. It is recommended to improve the fusion performance of multiple sensors in mines, study adaptive perception algorithms in mines, and break through the intelligent networked collaborative perception technology in mines.

The current research on intelligent coal mines focuses on top-level design, theoretical architecture, core technologies, control platforms, construction routes, standard development and evaluation systems, etc. There is no research on the technical research before and after the release of The guiding opinions on accelerating the development of intelligent coal mines. Intelligent coal mines are technology-intensive and capital-intensive, and need to be guided by policies to form a joint force which brings the government, academia, industry, finance and users together. Using CNKI (China National Knowledge Infrastructure) as a tool, this paper analyzes the current status of intelligent coal technology research, hot spots of concern and major research institutions. This paper summarizes the current status of intelligent coal mine policy development at the national level and in major coal-producing provinces such as Guizhou, Shandong and Shanxi. Although there are slight differences in the starting point and implementation progress of intelligent coal mines, all provinces have issued guiding documents in terms of implementation methods and acceptance and grading, and have made attempts to develop standards and establish innovative R&D centers to accelerate the pace of intelligent coal mine research and construction.

Mine moving target positioning system provides location-based services for intelligent construction of coal mines. However, most of the traditional mine positioning systems use single or combined communication technologies between positioning beacons and positioning tags with inflexible structure, limited coverage, low robustness and limited positioning accuracy. Using single or combined ranging technology, the optimal ranging technology cannot be selected adaptively according to different usage scenarios. For the position solution algorithm is fixed, the optimal solution algorithm cannot be selected adaptively according to different usage scenarios and signal changes. Hence, a new paradigm for all source mine positioning service is proposed, which can dynamically select the optimal combination of devices that meets current needs from all available positioning signal measurement devices according to the changes of the positioning environment and the target bearing platform. The paradigm can select the optimal combination of algorithms from the available ranging algorithms, positioning solving algorithms and result optimization algorithms adaptively to calculate the optimal position of the target node. In this study, all source mine positioning system architecture is designed, the available positioning signal measurement devices in mines and the types of measurement attribute values that can be used for positioning are discussed, and the functional differences of positioning servers between single mine positioning and all source mine positioning are compared. This paper discusses three key technologies in all source mine positioning service: unified positioning framework technology, which aims to meet the modular, combined and expandable needs of all source positioning; all source positioning information fusion technology, which organizes the measured attribute values to improve positioning accuracy; communication and positioning integration technology, which simplifies the design of all source mine positioning system and improves positioning accuracy through the positioning capability of wireless communication network itself. This paper proposes the implementation architecture of a terminal-edge-cloud based all source mine positioning system in order to fit in with the mainstream construction mode of intelligent coal mine and reduce the implementation difficulty and system cost significantly.

Due to complicated underground environment, traditional active location technologies make it inconvenient for workers to carry tags or lose tags during operation, which are limited in application of underground target location, while existing passive location technologies such as geometric method, fingerprinting method and so on has low location precision due to dense multipath interference in underground, which cannot be used in underground directly. For the above problems, a mine tagless target location method based on combined space and frequency diversity is proposed. The method, which is based on non-uniform sampling principle in Fourier domain, reconstructs target reflectivity function through inverse Fourier transform of echo signals of the target in wavenumber domain, so as to realize target location. Passive broadband harmonic tags are used to generate the required harmonic signals for eliminating fundamental frequency interference introduced by transmitting antenna. The combination of space and frequency diversity is achieved by using space diversity of the tags and frequency diversity of the harmonic signals and fusing multi-channel information, which solves the problem of low location precision caused by insufficient sampling information. A differential reception algorithm is used to eliminate phase errors caused by downlink multipath interference, which can improve mine tagless target location precision. The simulated experiment results show that the method can effectively expand coverage of wavenumber domain and restrain multipath interference, so as to realize accurate target location. Under the condition of low signal-to-noise ratio, the location precision can reach decimeter level.

Existing communication technologies of underground wireless sensor network such as ZigBee, ultra wide band, WiFi and so on have some shortcomings, for example, transmission distance is short, transmission rate is low, or coverage and access devices are limited. However, IEEE 802.11ah protocol meets requirements of transmission range, power consumption, network capacity and transmission rate of underground wireless sensor network, and can be used for underground monitoring sensor network to transmit periodic monitoring data. For problems of inflexible grouping for sensor nodes and load imbalance among groups existed in standard restricted access window (RAW) mechanism of MAC layer in 802.11ah protocol, a RAW regrouping method based on time delay optimization was proposed, which regrouped all the sensor nodes for three times according to projected transmission time of data packages, so as to decrease node colliding in a RAW group and transmission time delay. In order to realize RAW regrouping, an assignment identifier(AID) group reassignment method was proposed, which redistributed AID to sensor nodes group by group according to regrouped RAW group and made the AID map to MAC of the nodes by use of part nodes disconnecting access point, so as to decrease RAW regrouping time consumption and avoid network performance degradation caused by no data transmission during AID redistribution. The simulation results show that when underground monitoring sensor network adopts the RAW regrouping method, the network has less time delay, larger throughput and lower packet loss rate than the standard RAW mechanisms with sensor nodes increase, and regrouping process has little influence on the network performance.

In order to improve transmission performance and increase transmission distance of magnetic induction through-the-earth communication system, multiple input single output (MISO) magnetic induction through-the-earth communication system was studied. A MISO model was established and KCL equations were built according to Kirchhoff law, so as to get transmitting and receiving power. Path loss of MISO magnetic induction through-the-earth communication system was analyzed. Magnetic induction density of MISO model was researched and signal transmission characteristics of MISO magnetic induction through-the-earth communication system were obtained. The results show that: When transmitting coils have the same current, path loss of MISO model is significantly lower than that of single input single output (SISO) model.The more transmitting coils there are, the smaller the path loss will be. When transmitting power is the same, receiving power is proportional to the number of transmitting coils, and magnetic induction density at receiving end increases with the number of transmitting coils increases. The MISO model can effectively increase transmission distance of magnetic induction through-the-earth communication system. When all transmitting coils have the same current, transmission distance of MISO(1,2) model is about 1.11 times than that of the SISO model, and the transmission distance of MISO(2,2) model is about 1.26 times than that of the SISO model.

In view of need of safety monitoring wireless sensor network in special communication environment of underground coal mine and limitation of access device number and transmission distance of existing safety monitoring wireless sensor network, IEEE 802.11ah was applied to underground safety monitoring wireless sensor network, and NS-3 simulation platform was used to analyze its performances, such as transmission distance, throughput, delay, energy consumption.The analysis results show that the transmission distance of IEEE 802.11ah is much longer than that of traditional WiFi communication technology,and the packet loss rate of IEEE 802.11ah is still 0 when the transmission distance is 600 m. When the number of nodes is small and the network is not saturated, and the channel competition and collision of nodes are not serious, the performance advantages of IEEE 802.11ah in terms of throughput, time delay and energy consumption are not obvious. However,when the number of access nodes is large, IEEE 802.11ah can well guarantee the performances of throughput, time delay, energy consumption. As the number of access nodes increases after network saturated, performance of the traditional WiFi communication technology network continues to drop sharply, performance of IEEE 802.11ah declines less and becomes gradually stable. In addition, performance of IEEE 802.11ah network uplink data transmission is related to selection of restricted access window parameters, accurate selection of restricted access window parameters can better exploit performance advantages of underground safety monitoring wireless sensor network based on IEEE 802.11ah.

In underground mining process, variety of roadway surrounding rock structure has obvious non-linearity characteristic, and larger coal-rock dynamic disasters are triggered easily. Existing monitoring technologies for roadway surrounding rock in deep underground are based on data collection of single physical quantity and lack joint monitoring and analysis of multi physical quantities, which are unable to correctly judge deformation state of surrounding rock structure. For above problems, existing monitoring technologies for roadway surrounding rock in deep underground were analyzed including drilling cuttings method, core disking method, stress measuring method, surrounding rock deformation monitoring method, electromagnetic radiation method, acoustic emission method, microseism monitoring method, seism tomography method, etc. A formulation of multi-source and multi-field monitoring system for roadway surrounding rock structure in deep underground was proposed, which was built by use of informatization technology for roadway surrounding rock structure monitoring in deep underground. Key technologies of the informatization technology were expounded form aspects of data perception, collection, transmission and analysis. What's more, some challenges of the informatization technology were discussed including energy supply of sensor nodes in limited environment, unified interaction of heterogeneous sensor and data transmission of time-delay sensitive network.

For application requirements of safety monitoring in complex underwater environment, wireless magnetic induction communication technology was adopted to be information transmission technology. Principle of underwater wireless magnetic induction communication was introduced. Design scheme of an underwater wireless magnetic induction communication platform based on FSK modulation was expounded and communication test was taken out by use of the platform in simulated underwater environment. The test results show that the platform can realize wireless information transmission in underwater environment. The platform using unidirectional antenna will have communication interruption under the condition of changing position or angle of receiving antenna. While the platform using omnidirectional antenna can communicate normally in process of changing position or angle of receiving antenna, which improves communication reliability.

In view of problem that magnetic signal propagation had significant directionality, but effect of antenna position and angle on transmission performance in magnetic communication had not been fully considered by current researches, magnetic signal transmission characteristics of three kinds of antenna models of underground magnetic induction communication were researched including double-coil array and four-coil array in 2D antenna array and 3D coil model. Firstly, expressions of corresponding magnetic induction intensity and mutual inductance between sending coil and receiving coil were given according to mathematical models of the three antennas. Secondly, magnetic induction intensity was simulated and analyzed. Position and angle of receiving antenna were optimized according to magnetic field distribution. Finally, transmission performances of the three antenna models were compared, and influences of offset of each sending coil and vertical distance between sending coil plane and receiving coil plane on magnetic induction intensity were given. The research results are as follows: ① Magnetic induction intensity of 2D antenna array model and 3D coil model has symmetry and directionality. ② Transmission direction of 2D antenna array model changes from multiple directions to one direction as the vertical distance increases. ③ When parameters of sending coils are as the same, transmission distance of 2D antenna array model is greater than that of point-to-point communication system and 3D coil model. The more the number of sending coils, the farther transmission distance of 2D antenna array model is. But magnetic induction intensity rapidly decreases as the vertical distance increases. ④ 3D coil model has the same distribution of magnetic induction intensity in three coordinate axes. Magnetic field of 3D coil model is the most widely distributed, but norm of magnetic induction intensity is less than the one of 2D antenna array model.

For the problems of low working efficiency and poor quality caused by artificial information acquisition existed in traditional weighbridge weighing management systems of coal mine as well as frequent coal stealing phenomenon caused by lack of cheat-prevention measures, a video cooperated intelligent identification weighbridge management system for coal mine designed. The system composition, principle of video cooperated intelligent identification weighbridge, system working flow and software functions were introduced in details. The system is composed of video monitoring system, vehicle capture system and data acquisition system, and realizes intelligent monitoring for weighbridge business in coal mine based on license plate recognition and multi-feature matching by use of technologies of digital image processing, convolutional neural network and computer network. The application results show that the system has high reliability with simple operation, which decreases artificial workload effectively and prevents chat and coal stealing phenomenon.

Research status of existing wireless through-the-earth communication was comprehensively analyzed, performances of ground electrode, elastic wave and magnetic induction communication were compared, and result was got that performance of the magnetic induction communication is better than the other two kinds of communication methods. The magnetic induction communication model was emphasized, and on this basis, key technical problems and feasible solutions of the magnetic communication were put forward. Besides, design schemes of existing magnetic communication transmitter and receiver were elaborated. The future research directions of through-the-earth communication was put forward considering current studies and popular applications: large magnetic signal fading is a key factor which restricts further development of the magnetic induction communication; transmitter, receiver and transmission mechanisms of the magnetic induction communication need to be improved; through-the-earth communication system used in underground mine not only needs to control transmission power in safety range, consider compromise relationship between communication distance and transmission power, but also needs to consider how to suppress complex underground electromagnetic interference.

In view of requirements of security and environmental monitoring in coal mine multiplex medium in challenging environment, in order to conquer the obstacles such as serious path loss, dynamic channel condition and constrained supply condition and so on, theory model of wireless magnetic induction communication and magnetic induction waveguide communication in multiplex medium was proposed, and structure of wireless magnetic induction sensor network was given. Research directions and application of wireless magnetic induction sensor networks in the future were prospected, the urgency of related study was pointed out. It has great significance to safety monitoring of underground environment and the oil, gas or water pipeline which is especially long or in densely populated area.

The multi-relay cooperative communication system model in rectangular tunnel based on multimode channel model was established, and the channel capacity calculation formulas of multi-relay cooperative communication system in amplify and forward mode and decode and forward mode were given. Under the circumstance of limited power in tunnel, optimal power allocation method of amplify and forward multi-relay cooperative communication system based on genetic algorithm and multiple KKT optimal power allocation method of multi-relay cooperative communication system in decode and forward were proposed to optimize the channel capacity. Simulation results show that the proposed optimal power allocation methods can improve channel capacity of the tunnel multi-relay cooperative communication system.