| Our country is rich in coal resources, due to the complexity of the mine environment, the frequent accidents, improve the personnel positioning accuracy, position and for timely and accurate grasp the men, to ensure staff safety and coal mine enterprise management is very important. Due to the particularity and complexity of the mine roadway electromagnetic wave propagation, the realization of the mine personnel positioning become difficult in the field of wireless communications. And ranging is the basis of the positioning, so the paper researches a multiple antenna ranging method based on RSSI.This paper introduces transmission environment of electromagnetic wave in the roadway, analyses electromagnetic wave mode in rectangular tunnel model, deduces electromagnetic wave attenuation rate, and simulates intensity distribution characteristics of electromagnetic field in the roadway. Through the analysis, intensity distribution in the roadway appears fast fading phenomenon in close space field, and has obvious cyclical fluctuations. In terms of weakening the field intensity of cyclical fluctuations, multiple antenna distance measurement method is put forward, and has made the theory simulation confirmation. Multiple antennas ranging system is designed, two main aspects of the system including hardware and software.The paper determines the RSSI ranging model, use the Gauss filter to process the measured data, use the method of curve fitting to measure model parameters in the factor and attenuation factor. Finally, the ranging data of single and multiple antennas are analyzed and compared, the ranging accuracy of multi antenna is higher than the single antenna, and antenna spacing is two times of the wavelength get the highest accuracy, proved the effectiveness of the multi antenna measurement methods. |
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