Indoor Location Basedon Bluetooth RSSI Ranging

In recent years,the application of location-based services has become more and more widespread,and people pay more and more attention to it.Location is the primary problem to be solved about location service.Although GNSS provides an effective outdoor positioning method and becomes a necessary tool for many people,due to the influence of building occlusion,satellite signal is greatly weakened,and indoor location accuracy is greatly reduced,so that it is impossible to calculate the location of the equipment.According to statistics,more than 70% of human time is indoor,so solving the problem of indoor location has become the focus of current research.At present,Bluetooth positioning technology has been widely used because of its low cost,low power consumption,high accuracy and easy promotion.However,the indoor environment is relatively closed,positioning equipment is vulnerable to temperature,humidity,pressure and other effects.In addition,the signal is vulnerable to furniture,room obstacles and walking people during the transmission process,which makes the signal intensity unstable and affects the positioning accuracy.Calculate the coordinates of points with the help of sensors such as orientation and acceleration in smart phones,however,the coordinates are easily affected by the starting point and error accumulation.This paper focuses on the problems of Bluetooth indoor location technology and the solution strategy of integrating Bluetooth location and dead reckoning.The main works can be summarized as follows:(1)Firstly,long-distance RSSI is filtered to overcome the phenomenon that RSSI is no longer sensitive to distance when the distance reaches a certain level.Then,based on the location principle of measurement edge positioning,considering the disturbances of personnel and vehicles as abnormal errors,the coordinates of locating points are calculated by robust estimation principle,which can weaken the influence of multi-path effect and personnel disturbance.Experiments show that this method can significantly improve positioning accuracy.(2)Bluetooth positioning and dead reckoning are fused,and the Kalman filter principle is used for navigation calculation to make up for the shortcomings of Bluetooth positioning and dead reckoning.In order to determine the weights of the observation equation and the state equation reasonably,the variance component estimation method is used to determine the adaptive factor,The weight ratio problem is well coordinated by adaptive Kalman filter principle.The results show that this method can improve the positioning accuracy to a certain extent.(3)This paper tries to design function of indoor location system and the database based on Android system.It lays a foundation for further development of indoor location system.