| China is a country rich of coal and poor in oil and gas,and the coal is the main energy source of China,and will still be the main energy source of China for a long time.The coal industry is a high-risk industry.Gas,flood,fire,roof,transportation,electromechanical,blast and other accidents plagues the safety of coal production.In order to curb over-capacity production in coal mines and to avoid or reduce major accidents in coal mines,the government requires coal mines to be equipped with coal mine personnel positioning systems.Underground coal mine personnel positioning system plays an important role in coal mine safety production,accident emergency rescue and accident investigation.However,due to the low accuracy of the existing coal mine personnel positioning system,and it cannot be located in two-dimensional,it is unable to meet the needs of coal mine accident emergency rescue,transportation,electromechanical accident prevention and control.Therefore,for the special underground coal mine environment and coal mine safety production requirements,it is necessary to study the underground coal mine accurate personnel positioning method and two-dimensional positioning method,which has important theoretical and practical value for promoting the safe production of coal mines and the development of underground coal mine positioning technology.The characteristics of underground coal mine personnel positioning are analyzed and summarized: coverage is much larger than the ground floor;positioning signal should be able to transmit non-line-of-sight;the attenuation of radio signal transmission is serious,GPS and other satellite positioning signals cannot penetrate the coal seam and rock layer to reach the underground coal mine;,the attenuation of wireless transmission is affected by the gallery branching,bending,inclination,the area and shape of cross-sectional,the medium of surrounding rock,the roughness of gallery surface,support,longitudinal conductors(cables,rails,water pipes,etc.),transverse conductors(I-beam support,etc.),equipment and etc.,radio transmission attenuation model is complex and changeable;the equipmentmust be electrical explosion-proof;the underground coal mine environment is harsh because of dust,moisture,water and etc.Ultrasonic,infrared,laser,radio wave and other ranging technologies applied in underground coal mine are studied.Ultrasonic,infrared,and laser technologies can be used for straight-line obstacle-free distance measurement,which requires no obstructions in ranging area,such as rubber wheel vehicles,electric locomotives,belt conveyors,mobile substations and other equipment and operators,and branching,bending,inclination of galleries affects the measurement accuracy as well.Therefore,infrared,ultrasonic and laser ranging technologies are not suitable for the underground coal mine personnel positioning.Radio waves have the advantages of long transmission distance,non-line-of-sight transmission,and low equipment cost.By using time ranging methods,radio waves can solve or reduce the impact on the positioning accuracy from the branching,bending and inclination of galleries,and obstructions such as rubber wheel vehicles,electric locomotives,belt conveyors,mobile substations and other equipment and operators,and is suitable for underground coal mine personnel positioning.The underground coal mine positioning methods based on received signal strength indication(RSSI)and based on angle of arrival(AOA)are studied.The accuracy of the RSSI ranging and positioning method is affected by signal transmission power and receiving sensitivity,galleries and their supports,conductors and equipment in galleries,and the ranging and positioning error is large.The RSSI positioning method is not suitable for the underground coal mine accurate personnel positioning.The AOA positioning method can only be used for straight-line obstacle-free distance measurement,and the accuracy is affected by branching,bending and inclination of galleries,obstructions such as rubber wheel vehicles,electric locomotives,belt conveyors,mobile substations and other operators,and especially positioning antennas and their positioning accuracy affected by mechanical vibration,etc.The AOA positioning method is not suitable for the underground coal mine personnel positioning.The ranging and positioning methods based on signal transmission time ranging such as ranging based on time of arrival(TOA),ranging based on two way ranging(TWR),ranging based on symmetrical double-sided two way ranging(SDS-TWR)and ranging based on time difference of arrival(TDOA)are studied,and the ranging and positioning error of these positioning methods are studied as well.The ranging and positioning methods based on signal transmission time ranging,such as TOA,TWR,SDS-TWR and TDOA,are less affected by the gallery environment,and can be used for underground coal mine accurate personnel positioning.The TOA positioning method requires that the time between positioning substation and positioning card must be synchronized,and timing must be accurate,the cost of the positioning card and the positioning substation is high,the time synchronization between positioning substation and positioning card is difficult.The TDOA ranging and positioning method requires that the time between positioning substations must be synchronized,and timing must be accurate,the cost of the positioning substation is high,the time synchronization between positioning substations is difficult.The TWR and SDS-TWR ranging and positioning methods do not require synchronization between positioning substation and positioning card,do not require synchronization between positioning substations,and do not require synchronization between positioning cards,which reduces the system complexity and cost,however,the ranging and positioning accuracy is affected by the clock timing error of the positioning substation and the positioning card,therefore the positioning card and the positioning substation cost high,TWR and SDS-TWR ranging and positioning methods are suitable for the underground coal mine accurate personnel positioning.To improve positioning accuracy and reduce the cost of positioning card and system,proposing asynchronous time-measuring underground coal mine accurate personnel positioning method: positioning substations are installed interval at certain distance in the underground gallery,and ensure that the two neighboring positioning substations can communicate with each other wirelessly and the positioning card can communicate with two neighboring positioning substations at the same time.Any one initial positioning substation sends a ranging signal to the positioning card and the neighboring positioning substation in the communication range,the neighboring positioning substation receives the ranging signal and then sends a ranging signal to the positioning card,the positioning card reply response signals to the initial positioning substation and the neighboring positioning substation separately.After receiving the response signal replied from the positioning card,the initial positioning substation calculates the time between sending and receiving the ranging signal.After receiving the response signal replied from the positioning card,the neighboring substation calculates the time between sending and receiving the ranging signal,and sends the time to the initial positioning substation.According to the time between sending and receiving the ranging signal calculated by the initial positioning substation and the neighboring substation separately,the signal transimission speed,and the distance between the initial positioning substation and the neighboring substation,the initial positioning substation calculates the distance between the positioning card and the initial positioning substation and the distance between the positioning card and the neighboring substation.Measuring distance by asynchronous time-measuring underground coal mine accurate personnel positioning method is only related to the time of sending and receiving ranging signal from the substation and not related to the signal strength,the accuracy of positioning is not affected by the signal transmission power,receiving sensitivity and signal transmission attenuation.Asynchronous time-measuring underground coal mine accurate personnel positioning method is not related to the clock of the positioning card,which greatly reduces the complexity and cost of positioning cards,the cost of positioning cards is low;Asynchronous time-measuring underground coal mine accurate personnel positioning method does not need time synchronization between positioning substation and positioning card,does not need time synchronization between positioning substations,and does not need time synchronization between positioning cards,reduces the complexity and cost of positioning substations,the cost of positioning substations is a little high.Analysis and experiment show that the main performance indicators of asynchronous time-measuring underground coal mine accurate personnel positioning method are superior to SDS-TWR and other underground coal mine positioning methods.In order to meet the needs of underground coal mine two-dimensional accurate personnel positioning to meet the emergency rescue of coal mine accidents and the control and prevention of electromechanical transport accidents,proposing underground coal mine geometric two-dimensional accurate personnel positioning method: positioning substations are installed interval at certain distance in the underground gallery,in underground galleries,positioning substations are arranged along one side of the gallery,and ensure that the positioning card can communicate with two neighboring positioning substations at the same time.The adjacent two positioning substations of any positioning card use TWR or SDS-TWR ranging method to measure the distance between the positioning card and the two positioning substations respectively.Since the distance between the two positioning substations is known when positioning substations are installed,based on the distance between the positioning card and the two positioning substations and the distance between the two positioning substations,the gallery horizontal radial distance between the positioning card and the positioning substations,and the gallery axial distance between the positioning card and the positioning substations are calculated,then according to the position coordinates of the two positioning substations,calculate the two-dimensional position coordinates of the positioning card in underground galleries.Analysis and experiment show that underground coal mine geometric two-dimensional accurate personnel positioning method has the advantages of small calculation amount,fast positioning speed,less use of positioning substations,low cost of positioning cards and positioning substations.To reduce the effects on positioning accuracy from clock timing error,multipath effect,NLOS delay error,electromagnetic harassment and etc,and to improve underground coal mine two-dimensional personnel positioning accuracy,applying Kalman filter in underground coal mine two-dimensional personnel accurate positioning: the distance between positioning card and positioning substation measured by the positioning substation is taken as measurement result of Kalman filter,the miner's position is calculated by established mathematical model of underground miner movement,which is taken as prediction result of Kalman filter.The measurement results and the prediction results were weighted reasonably,the best estimate at the current time is obtained from the best estimate after the previous step by Kalman filter,as to realize two-dimensional accurate personnel positioning in underground coal mine.Analysis and experiment show that underground coal mine two-dimensional personnel accurate positioning method based on Kalman filter reduces the effects on positioning accuracy from clock timing error,multipath effect,NLOS delay error,electromagnetic harassment and etc.To further eliminate the effects on positioning accuracy from clock timing error,multipath effect,NLOS delay error,electromagnetic harassment and etc,and to achieve underground coal mine two-dimensional accurate personnel positioning,proposing underground coal mine two-dimensional accurate personnel positioning method based on curvilinear component analysis(CCA),the three-dimensional space is simplified to a two-dimensional plane by curvilinear component analysis,in the dimension reduction process,the goal is to keep the distance between the positioning card and positioning substations as constant as possible,and the coordinates of the positioning card in the two-dimensional plane are calculated by iterative updating the minimum cost function.Analysis and experiment show that underground coal mine two-dimensional accurate personnel positioning method based on curvilinear component analysis can effectively eliminate the positioning error,improve the positioning accuracy,and achieve two-dimensional accurate positioning.For the needs of underground coal mine accurate personnel positioning for coal mine safety production and accident emergency rescue,designing the underground coal mine accurate personnel positioning system,including system function requirement analysis,system overall design,positioning substation design,positioning card design and etc.The underground coal mine accurate personnel positioning system mainly includes positioning substations,positioning cards,mining Ethernet,positioning storage servers,geographic information servers,monitoring terminals,remote monitoring terminals and etc.The main innovative works of this article are as follows:(1)Propose asynchronous time-measuring underground coal mine accurate personnel positioning method,which does not need the synchronization between the positioning card clock and the positioning substation clock,the synchronization between positioning substations clock and the synchronization between positioning cards clock,and eliminates the influences on position accuracy from the positioning card clock timing error.Analysis and experiment show that the main performance indicators of asynchronous time-measuring underground coal mine accurate personnel positioning method are superior to the SDS-TWR and other underground coal mine positioning methods.(2)Propose underground coal mine geometric two-dimensional accurate personnel positioning method,analysis and experiment show that underground coal mine geometric two-dimensional accurate personnel positioning method has the advantages of small calculation amount,fast positioning speed,less use of positioning substations,low cost of positioning cards and positioning substations.(3)Propose underground coal mine two-dimensional accurate personnel positioning method based on curvilinear component analysis(CCA),analysis and experiment show that underground coal mine two-dimensional accurate personnel positioning method based on curvilinear component analysis can effectively eliminate the positioning error,improve the positioning accuracy,and achieve two-dimensional accurate positioning.(4)Apply Kalman filter in underground coal mine two-dimensional personnel accurate positioning,analysis and experiment show that underground coal mine two-dimensional personnel accurate positioning method based on Kalman filter reduces the effects on positioning accuracy from clock timing error,multipath effect,NLOS delay error and etc.(5)Analyze and summarize the characteristics of underground coal mine personnel positioning.Propose that ultrasonic,infrared,and laser ranging technologies are not suitable for underground coal mine personnel positioning,while radio ranging method is suitable for underground coal mine personnel positioning.Propose that the RSSI positioning method is not suitable for underground coal mine accurate personnel positioning,the AOA positioning method is not suitable for underground coal mine personnel positioning,the TOA and the TDOA positioning methods can be used for underground coal mine accurate personnel positioning,the TWR and the SDS-TWR positioning methods is suitable for underground coal mine accurate personnel positioning. |
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