Research On Through Rock Wireless Communication System For Emergency

In the underground mine accident rescue, using a excellent communicationsystem can timely issue alarm singal, direct the rescue and improve rescue efficiency,so, it is essential to ensure rescue smoothly. However, the traditional wiredcommunication lines are vulnerable to natural disasters, poor anti-accident, and itcan only play a role in the daily production and can not assume the important task ofrelief and rescue, thus wireless communications are gradually being put on theagenda. Utilizing Wirelessly transmitted through the strata, two-waythrough-the-earth wireless communication can made the signal transmitted directlybetween the underground mine and the mine surface central station, which isconsidered to be the most feasible method in underground emergency rescue. But,due to the complexity of its the electromagnetic environment of its transmissionchannel-the earth medium and the attenuation in which the electromagnetic wave istransmitted and severe interference, to achieve long-distance underground wirelesstransmission has been the existence of difficulties.On the basis of detailed analysis of the mine communication systemdevelopment at home and abroad, this subject makes the underground emergencycommunications as the main goal, and combines the characteristics of theunderground communications environment, uses the adventage of wirelesscommunication, applys a combination of theoretical analysis and experimentalresearch, and finally researchs the design method of the low frequencythrough-the-earth current field communication system. The subject first introducesthe design requirements of the emergency communication system, discussed andanalyzes the characteristics of communication channel-the earth, researchs theelectromagnetic attenuation in the earth, and calculates and determines the suitableworking frequency band adopted by current field communication system. Thenusing the methods of the dipole and electrostatic, it analysises field current fieldcommunication, calculates the distribution law of the current field, and takes thesimulation experiment verified the theoretical, analysises the factors affecting thecurrent field of communication. Finally the current field communication system isdesigned, and develops signal front-end equipment including a low-frequencyvoltage amplifier, filter,notch filter and so on, communications experiments arecarryed out, the experiment receives the transmitted signal in the transceiverdistance of20m，which proves the feasibility of the communication system.The main purpose of this paper is to analysis the communication theory of thecurrent field, theory and to design through-the-earth communication systems, By the experiments it is proved that through-the-earth communication by the current fieldmethod is feasible. The contents of this subject can not only be used forunderground emergency communications, but also can play a role in the dailyproduction of underground mine, and also provides some guiding significance ofunderwater communication additionally.