Research On Multi-antenna Ranging Algorithm Based On RSSI

At present,the positioning method of coal mine positioning system is related to the ranging.Measuring the distance between the receiving antenna and the transmitting antenna to be positioned,the accuracy of the positioning is directly affected by the accuracy of the ranging.Due to the complexity of the mine environment,the attenuation index of the path changes when the environment changes.It results serious multipath effect in wireless signal propagation process,so that largely suppress the application of RSSI(received signal strength)in coal mines.Therefore,the thesis researches the filtering algorithm in multi-antenna receiving system to improve RSSI precision.Firstly,this thesis introduces transmission environment of electromagnetic waves in coal mine.The electromagnetic wave model is analyzed by establishing the ideal rectangular roadway model,and then deducing the attenuation rate of the horizontal polarized wave and the vertically polarized wave,and simulating the attenuation of the electromagnetic wave in the emulation roadway.The simulation results show that the fading characteristic of the electromagnetic waves in the large-scale fading occur at the close distance,or the large-scale fading occurs in the long distance is periodic fluctuation..The improved Gaussian-Kalman filtering algorithm is proposed to optimize the RSSI range system of multi-antenna to weaken the influence of periodic fluctuation and deep fading point on the accuracy of RSSI.Finally,simulating the multi-antenna ranging system and using improved gauss filtering and Kalman estimation to process the measured data,correcting the deep fading point,using the method of curve fitting to measure model parameters in the factor and attenuation factor of different antenna spacing.The ranging data of the single-antenna and the different distance of multi-antenna before and after filtering are analyzed and compared.The ranging accuracy of multi-antenna distance measurement system with improved Gaussian filtering and Kalman estimation is superior to the single antenna and multi-antenna distance measurement before filtering,and the antenna spacing is two times of the wavelength to get the highest accuracy increased by 25%.