Design And Implementation Of IBeacon Module With Low RSSI Fluctuation

With the popularity of iBeacon devices,indoor location service has gradually become a research hotspot,more and more researchers are using the iBeacon device as an anchor node to complete the indoor positioning function.However,in the indoor positioning system based RSSI,the fluctuation of the RSSI value caused the ranging error,then reduced positioning accuracy.Therefore,reducing the RSSI value fluctuation is important for the improvement of indoor positioning accuracy.The problem of locating error is caused by the large fluctuation of RSSI value in an indoor positioning system based on iBeacon equipment.in this thesis,firstly,the influence of the environment's noise on the fluctuation of RSSI is reduced by gaussian filter.Then,the RSSI value is compensated by the antenna radiation pattern in the darkroom according to the antennas.Finally,the purpose of reducing the RSSI value fluctuation,reducing the range error and improving the accuracy of indoor location is achieved.The whole method of reducing the volatility of RSSI values consists of the following three phases:The first phase,test anchor nodes' antenna radiation pattern in the darkroom,select the signal gain maximum Angle as a benchmark in the antenna radiation pattern,calculate the rest of the perspective and the perspective of benchmark relative signal strength value as the RSSI value compensation.The second phase,the RSSI values and the weighted centroid algorithm was used to calculate the initial position coordinates of the unknown nodes.The last phase,according to the initial position coordinates to calculate the unknown node and the relative angle between the anchor nodes,compensate the RSSI values,using the weighted centroid localization algorithm iterative calculation for unknown nodes coordinates,until the unknown node coordinates to a stable value.The experimental results show that,according to the antenna radiation pattern compensate RSSI values can obviously reduce the volatility of RSSI values,improve the indoor positioning accuracy.The result shows that the standard deviation of RSSI is less than 1.00,and the accuracy is less than 1.34 m.This thesis work to reduce the volatility of RSSI values,reduced the ranging error and improves the indoor positioning accuracy,for indoor location service has great engineering application value.