Design And Implementation Of Data Acquisition And Processing For Positioning System In Mine

At present, the attention of safe producing in coal mine has been increased to an unprecedented level by State, but accidents occur constantly in coal mine, and the poor rescue after the accident exposes the current monitoring system's flaws. For example, it's difficult to manage workers in time and it also can't position and track them.This paper initiates to resolve these issues and introduces the design and implementation of a positioning system in mine based on wireless sensor network technology. The system consists of data acquisition subsystem, data processing subsystem and management subsystem of ground control center. Data acquisition subsystem collections positioning data from mobile positioning terminal, and then sends them to data processing subsystem, data processing subsystem calculates the position of worker in mine accurately after analysis the information, and then sends the results to the management subsystem to complete the real-time positioning and tracking of workers in mine.This paper introduces several typical routing protocols and positioning algorithms in wireless sensor networks, analyses their advantages and disadvantages, and then the location principle is proposed based on the practical situation. The requirements and functions as well as the composition and structure of the system are introduced. The communication protocols between each subsystem are also presented in detail. Lastly, the paper expounds the design and realization of the acquisition subsystem and processing subsystem, including the design of program framework, routing protocols, I/O communication program and the location algorithms in detail.In addition, the paper analysis the propagation model of the 2.4GHz wireless electromagnetic wave in free space. According to the special surroundings of laneway in coal mine, piecewise fitting is made after considering the differences of wireless electromagnetic wave's propagating property between theory and practice seriously; different laneway's propagation model is showed by different piecewise function. The concept of path is proposed based on the structure feature of laneways in coal mine, as well as the positioning algorithm based on RSSI. Through lots of experiments, the results showed that the accuracy of the positioning algorithm meets the requirements of large-scale coal mines.