Research On Re-localization Method Of Drift Nodes After Coal Mine Disaster

Coal is the main energy source of energy in China.Coal mining has been threatened by gas,roof,hydropower and other disaster for a long time.So ensuring production safety is the top priority of work.Usually,a large number of wireless sensor nodes are arranged in underground coal mines,which can collect the underground environmental conditions,workers' location,equipment running state and other information,so as to carry out real-time monitoring of production safety.After the coal mine disaster,it is the key to improve the emergency response speed and rescue efficiency to accurately locate the localization of the trapped people and plan the rescue route.However,there are two difficulties in the re-localization of coal mine after disaster.On the one hand,the beacon nodes arranged before the disaster drift,and the localization of these beacon nodes is difficult to determine after the disaster,so the localization accuracy is greatly reduced.On the other hand,there are many obstacles in the underground coal mine,and the localization and motion state of the obstacles are uncertain,which makes the localization environment more complex.The ranging is affected by NLOS propagation,resulting in serious localization errors.According the above mentioned two aspects problem,this paper studied the beacon selection problem after coal mine disaster.On the one hand,various factors affecting the credibility of beacon are analyzed theoretically.On the other hand,from the perspective of experiment,the environmental factors were measured by UWB experimental equipment,and the proportion of environmental factors was calculated.ATRL re-localization algorithm is proposed,comprehensive utilization of the AHP and the TOPSIS.The AHP model is established from three aspects including nodes relative drift distance,environmental factors and nodes energy.And it calculated the proportion of the influence of various factors.The reliability of drift nodes is calculated by TOPSIS algorithm,and the nodes with the highest reliability are selected as re-localization beacons.The simulation shows that ATRL algorithm has great advantages in localization success rate and localization error,and can meet the basic requirements of coal mine rescue after disaster.Then,this paper studies the precise localization algorithm under the NLOS scenario in underground coal mine.The Identification algorithm based on geometry difference is put forward,and the boundary between LOS and NLOS path is obtained by using the method of theoretical deduction.The parameter values with the highest identification accuracy are calculated by MATLAB simulation.The simulation results show that the NLOS propagation identification accuracy of IGD algorithm reaches88.2%?98.9%.The advantage of IGD algorithm is not only high accuracy,but also low complexity and fast identification.Then,the semi-positive definite algorithm with prior information is proposed by making full use of the identification information of IGD algorithm.The simulation results show that the NLOS error is effectively suppressed and the localization accuracy is effectively improved by using IGD-SDP algorithm to locate.Finally,this paper simulates and programs the rescue path after the disaster of Xinqiao Coal Mine.Combine with the research results of the third chapter,use ATRL algorithm to calculate the degree of regional disaster after the disaster,and combine with the research results of the fourth chapter,use IGD-SDP algorithm to calculate the degree of blocked path.Select the optimal rescue path,realize the scientific guidance of the rescue path programming after the disaster of coal mine,ensure the safety of rescue and the efficiency of rescue.There are 43 figures,7 tables and 96 references in this thesis.