Research And Design Of Underground Locating Communication System In Mines Based On Frequency Hopping Technique

Underground communication in mines is a difficult problem now, since there are complicated multi-path and multi-address interferences in such environment, where surface ground communication system can not work well. Reliability of underground locating communication system (ULCS) in coal mines must be improved to meet the demand of safety production and scientific management in current coal mines.Through large number of experiments in the coal mine, the ULCS is analyzed and designed. This thesis consists of four parts. A novel system scheme is presented, according to the analysis and design of underground communication system.Firstly, the description of the ULCS hardware design is presented. Principle of the ULCS is discussed in detail. And the choices of components and kernel circuit schematics are proposed, which ensure the reliability of data transmission on hardware.Secondly, the description of the ULCS software design is presented. CSMA protocol is selected by wireless accessed protocol. Communication protocol and software scheme of base stations and cards is presented, which ensure the reliability of data transmission on software.Thirdly, the feature of wireless channel and module of encoded channel under mine are raised, and approach generated of frequency hopping sequences is emphasis. The construction of No-hit zone frequency hopping sequences based on interleave technique improved is presented, which was applied to the ULCS. The method solved the problem of multi-path and multi-address interferences.Fourth, analyse quality index of range transmitted and error rate of ULCS. Factual range transmitted and error rate can meet the needs of the ULCS.In addition, this system can be transferred to the other coal mines by modifying several parameters, which are estimated by measures of electromagnetism interference of every frequency channel. The ULCS has advantages of low cost, short developing cycle, easy installation and maintenance and excellent technical and economic benefit. The ULCS can be spread underground projects.