Research On Positioning Algorithm Of Coal Mine Personnel Based On TOA

Safety is the foundation of coalmine production,and accurate positioning of downhole targets is an important guarantee for coalmine safety.The underground coalmine personnel positioning system can locate the underground workers in real time,and provide important position information for underground emergency rescue,personnel operation management and mine loT construction.However,due to the long and narrow closure of the mine roadway,there is a serious non-direct path error and multipath fading phenomenon in the propagation of wireless signals,resulting in low positioning accuracy and poor adaptability of the cxurrent mine positioning system.Based on the analysis of some existing mine personnel positioning techniques and algorithms,this paper makes a deep research on the optimization algorithm of coal mine underground personnel positioning error based on time of arrival(TOA).Mine TOA is a positioning technology based on signal arrival time,which is susceptible to clock synchronization,timing offset and non line of sight(NLOS)propagation.In this paper,based on the symmetrical bilateral two-way ranging algorithm to effectively eliminate the synchronization delay and timing error,aiming at the problem that the positioning accuracy of mine TOA is susceptible to the propagation delay of electromagnetic wave NLOS,the NLOS propagation delay reference model of roadway electromagnetic wave is proposed by analyzing the NLOS propagation characteristics of mine electromagnetic wave and the movement characteristics of mine roadway equipment.According to the cause and characteristics of NLOS delay of roadway,it is divided into random NLOS delay and fixed NLOS delay,which provides a theoretical basis for the research of the latter optimization algorithm.A Kalman filter algiorithm based on the threshold of innovation is proposed for the random NLOS delay error caused by random and difficult quantitative analysis caused by mobile equipment such as locomotives in mine roadway and irregular installation equipment.Based on the classical Kalman filter algorithm,the improved algorithm introduces the concept of threshold of new interest rate,improves the filtering ability of Kalman filter for pulse error,and achieves the purpose of filtering out the random NLOS delay error of roadway.Aiming at the fixed NLOS delay error of the roadway with stability and certain regularity caused by the fixed facilities and equipment in the mine roadway,the parameter fitting and geometric positioning algorithm are proposed.The algorithm establishes the roadway ranging error model by parameterfitting,constructs the functional relationship between the inherent equipment parameters and the positioning estimation value,and uses the projection geometric algorithm to eliminate the drift phenomenon of the positioning point,effectively suppressing the NLOS delay error of the roadway.A lot of simulation experiments based on the innovation threshold Kalman filter and parameter-fitting algorithm proposed in this paper are carried out.Firstly,through the combination experiment of different innovation thresholds and parameter fitting values,the effects of the key parameters of the algorithm and the parameter fitting values on the proposed algorithm are discussed.The rationality of the proposed algorithm and the optimality of parameter design are verified.Secondly,through the simulation and comparison experiments of the system,the reliability and effectiveness of the algorithm proposed in this paper to suppress the NLOS delay of mine roadway are analyzed.The simulation results show that the positioning error of the measured data is 0～0.8m and the average error is 0.3m.Compared with the symmetric bilateral two-way ranging algorithm,Kalman filter and fingerprint localization algorithm and Karl Man filter and parameter-fitting algorithm,the average positioning error of the proposed algorithm is reduced by 3.4m,0.4m and 0.6m respectively.It shows that the proposed method has a significant inhibitory effect on the TOA positioning error,and can effectively implement the TOA method in the mine NLOS environment.