Research On Coal Mine Underground Positioning Technology Based On Visible Light

Coal mine underground positioning technology is of great significance for the safe mining of coal mines,the monitoring and scheduling of personnel,and the rescue after disasters.Due to the complex underground environment and limited technical difficulties,the effect of wireless positioning of underground targets is not satisfactory.Thanks to the advantages of visible light with small multipath effect,no electromagnetic effect,anti-electromagnetic interference,etc.,and the ubiquitous LED lighting equipment in the underground,the emerging visible light positioning(VLP)technology provides a new idea for underground positioning.However,the current research on underground VLP technology is imperfect and insufficient.To further explore the advantages of VLP technology in the underground environment,this thesis studies the underground positioning technology of coal mines based on visible light from the perspectives of reliability,applicability and practicability.(1)Aiming at the problem of unreliable optical signal reception due to the disadvantages of the transceiver deployment in the traditional underground VLP technology,the miner’s headlight is used as the transmitter to study the underground VLP method based on the transceiver inversion mechanism,the underground positioning model combined with visible light and inertial navigation is constructed,the selection and separation algorithm of visible light flashing frequency is designed for the special underground environment,the frequency power tracking algorithm is proposed to minimize the positioning error of the base station,and make a special miner’s lamp that can flash a specific frequency as soon as it is turned on,which effectively improves the reliability of the VLP technology in the underground environment.(2)Aiming at the problem of difficult underground deployment and the high cost of hard reconstruction caused by the use of modulated transmitters in the underground VLP technology,the unmodulated visible light transmitter is used to study the underground VLP method based on the rotary coding mechanism,polar coordinates are used to represent the target location,a distance calculation method combining Lambert’s cosine law and rotary coding is designed,and the angle calculation method combined with the reference line position and the rotation code is designed.The experimental results verify the superiority of this method,and only using the original LED light can achieve high positioning accuracy.(3)On the basis of the above research,this thesis further studies the safety monitoring method for mine cages based on VLP technology.Aiming at the safety hazard caused by the door of the underground mine cage is not airtight,the light intensity threshold monitoring algorithm is designed to realize the function of positioning the limbs of the mine cage personnel,the overload monitoring of the mine cage is realized by using the visible light flashing frequency separation algorithm,the personnel punching is realized by using the visible light flashing frequency identification algorithm,and the delineation method of mine cage safety area is proposed to realize the monitoring function of the mine cage safety area.The experimental results show that the accuracy rate of the proposed method is over 96%.In summary,this thesis studies the coal mine underground positioning technology based on visible light from the perspectives of reliability,applicability,and practicability,analyzes some problems existing in the current underground VLP technology,and proposes corresponding improvement methods.At the same time,the designed visible light transmitter and receiver are used in extensive experiments in the underground tunnel laboratory and other environments,and the experimental results verify the effectiveness of the methods proposed in this thesis.This thesis has 62 figures,9 tables,and 86 references.