Research And Implementation Of Adaptive AP Deployment Algorithm For Indoor Localization

With the rapid development of wireless communication technology,positioning technology has gradually entered the life of people,providing convenient services for the travel of people.In the indoor environment,various emerging indoor positioning systems have gradually become an indispensable navigation tool for people.Among them,the location fingerprint based indoor positioning technology has been widely concerned because of its advantages of no additional equipment and simple operation.In order to improve the positioning accuracy of fingerprint positioning system to meet diverse service needs of people,experts and scholars pay little attention to the layout of wireless Access Points(APs)in the research environment by improving the stability of the system and the positioning algorithm.This thesis mainly studies how to realize the adaptive layout of APs in indoor positioning system to improve the positioning accuracy of the system.Firstly,a new method is used to determine the indoor signal propagation model.In indoor scenes,multiple sampling points are set at equal intervals to collect signal intensity information,and the signal attenuation factor is fitted by least square method.When there is no obstacle between sampling point and APs,the logarithmic attenuation model is used.When there is obstacle between sampling point and APs,the signal penetration loss of obstacle is tested,and the signal attenuation model is determined by weight distribution method.Secondly,the loop coverage method is used to determine the number of APs deployed in the environment.In this thesis,the concept of effective coverage area and effective coverage Reference Points(RPs)are proposed.Then,the full and effective coverage of all reference points in the environment is achieved by using the loop coverage method.Next,the maximum probability method is used to determine the number of APs needed in the environment and its initial location.Furthermore,the mathematical model of adaptive APs layout is established.In this paper,the simulated fingerprint database is constructed based on the signal propagation model,and then the discrimination value of reference points is calculated using the signal Euclidean distance between reference points,and then the discrimination function of fingerprint database is established as the mathematical model of adaptive APs layout.Next,the proximity-greedy algorithm is used to realize the adaptive layout of APs.In this paper,the environmental information matrix is constructed based on the environmental information,and the simulation fingerprint database is constructed based on the initial selection of APs location and the signal propagation model.Then the proximity-greedy algorithm is used to optimize the local layout of a single AP in turn until the degree of fingerprint database is maximized and the adaptive layout of APs is realized.Furthermore,based on the above algorithm,the design of adaptive APs layout software is designed in this thesis.Finally,the Bluetooth indoor positioning system is used to build the experimental platform,and the adaptive APs layout algorithm proposed in this thesis is simulated in the test environment.By comparing with empirical layout method and improved genetic algorithm layout method,the experimental results show that the proposed algorithm not only has fast convergence speed and low complexity,but also improves the positioning accuracy of the system.