Research On High Precision Indoor Wireless Positioning And Tracking Technology

This dissertaion is related to the key technology of indoor wireless positioning and tracking system.Aiming at the present indoor wireless locating system,this thesis focuses on the two technologies of high precision indoor positioning and mobile tracking: the calculation of high precision indoor positioning algorithm with effective error prevention and tracking smoothing algorithm with low complexity high stability.First,this paper introduced several systems of indoor locating and their development,discussed the application potentiality in various fields,and pointed out the present key challenges.In terms of the indoor positioning algorithm and tracking smoothing algorithm,this paper analyzed the intended solution and technical routine by dissecting the features of indoor locating system.By analyzing the different indoor positioning algorithms and comparing various improvements and differences,this paper summarized the key problems which may appear in distance measurement and locating stage of indoor positioning algorithm: the smoothing of abnormal data,the select strategy of anchor nodes and the error control system.Further,this paper put forward an indoor positioning algorithm based on the anchor nodes selecting.This algorithm smoothing the abnormal data by secondary data screening,selects the anchor nodes combinations through point measurement within triangle,then quantizes the influence of different anchor combinations by introducing the triangle centroid positioning algorithm.Meanwhile,in order to remedy the defects of sole locating technology and to increase the data utilization rate,this paper proposed a fusion algorithm based on TOF and RSSI.Considering the respective features of two locating technologies,this fusion algorithm set the distance weighting factors,which solved the error problems in TOF short distance positioning and unreliability problems in RSSI long distance positioning by weighting fusing the two locating results,and then decreased the non-line-of-set error which may rise because of the environment by adding residual modification in maximum likelihood estimation method.In the aspect of tracing moving objects,the paper analyzed the defects of tracking smoothing algorithms and proposed the IMM-IUKF(Interaction Multiple Model-Iterated UnscentedKalman Filter)algorithm for overcoming the low speed,low accuracy and bad stability problems of the present smoothing algorithm.This algorithm based on the traditional UKF(Unscented Kalman Filter)speeded up the rate of convergence though improved the stability;at the same time,on the complexity of tracing and predicting moving targets,this algorithm uses interactive multimode frame and sets several state models before tracing the smoothing to increase the veracity of describing the present state of target and to increase the tracing accuracy by hybrid filter.The paper verified the tracing ability of IMM-IUKF algorithm by stimulating from the aspects of rate of convergence,tracing accuracy,stability and complexity.Finally,with a view to the general frame,this paper designed a centralized positioning and tracing system based on TOF,and designed the system software as three layers,and put forward the program implementation project relating to upper computer,Serial Communications,data basis and nodes communication.On the designation of hardware,the STM8L151C8 single chip is used as master control,Nano Loc RF module functions for distance measurement and communication,CH430 T chip is used for USB port.In the system debugging stage,three distance measurement experiments and locating experiments are designed to verify the feasibility of indoor positioning and tracing system.