Study On Indoor Localization Technology Based On WiFi And Bluetooth

Along with the increasing demand for location based services, people are not satisfied with the positioning and navigation application requirements using in the outdoor. Indoor positioning is becoming a hotspot of the location based service. Indoor positioning technology has been widely used in emergency rescue, warehousing logistics, personnel monitoring and other industries. As the core technology of indoor positioning, both WiFi and Bluetooth have good terminal support. WiFi indoor network has been widely covered and Bluetooth beacon is easy to deploy and the cost is low. Therefore, this thesis studies the following three aspects of indoor positioning technology and methods based on WiFi and Bluetooth:First of all, in order to reduce the influence of the pseudo range measurement error on the position estimation, the elimination of high-order weighted least square algorithm is proposed. First, the least square estimation of pseudo range is used to weaken the influence of non line of sight error and Gauss noise. Then, the elimination of high order method is used to solve the linearization of the observation equation. At last, the position coordinates of the terminal are estimated by the weighted least square algorithm. The simulation results show that this algorithm can effectively improve the indoor positioning accuracy and the positioning efficiency compared with the traditional three edge measurement method and the Taylor series method.Secondly, in order to make full use of WiFi and Bluetooth signals to improve the localization performance, this thesis presents the WiFi and Bluetooth indoor fusion location algorithm based on optimal Bayesian estimation. The test method is used to calculate the WiFi and Bluetooth positioning information source credibility. Then, the optimized Bayesian posterior distribution density function is used to estimate coordinate deviation and to correct positioning results fusion. The simulation results show that the algorithm is not only significantly improve the positioning accuracy, but also can significantly weaken the effect of noise on the Gauss localization algorithm compared to single location algorithm.Finally, in order to ensure the best positioning performance of the terminal in the mobile process under the heterogeneous network environment, a switching decision algorithm based on cost function is proposed to solve the ping-pong handover effect. This algorithm improves the cost function and uses stable periodic assessment decision algorithm. This algorithm realizes the efficient seamless switching between WiFi and Bluetooth heterogeneous network,and realizes the smooth transition of the indoor positioning switch.