Design And Implementation Of Indoor Positioning System Based On Relative Direction Angle Estimation

Effective supervision of detainees is a key prerequisite for maintaining social harmony and stability in prisons.With the continuous development of the society,modern prison management puts forward higher requirements for the supervision quality and supervision efficiency of detainees.The traditional prison management obtains the position information of detainees by means of “human supervision”.The supervision efficiency is low and the human burden is heavy.Unable to meet the regulatory needs of modern prisons.In recent years,the rapid development of indoor wireless positioning technology has brought new opportunities for changing the location information of detainees and improving the efficiency and quality of prison supervision.However,the indoor environment of the prison is complicated and there are many obstacles.The wireless signal transmission is susceptible to multipath interference and shadows,which leads to low indoor wireless positioning accuracy and poor stability.Aiming at this problem,this paper studies the relative estimation of relative direction angle and received signal strength indication(RSSI)based on the pre-research project of “Research on the Positioning Technology of Detainees in a Prison Factory”.Based on these technologies,a wireless indoor positioning system was designed and implemented.(1)Based on the application characteristics of the positioning technology in the prison factory area,the RSSI is determined as the basis for the research of positioning technology.Using the difference of radiant energy of different angles in the horizontal direction by directional antenna can accurately estimate the relative direction angle,but the traditional accurate estimation method of relative direction angle is susceptible to environmental interference,the angle estimation error is large,and the stability is poor.Therefore,this paper an accurate relative angle estimation algorithm(RDAE)based on mixed Gaussian model is proposed.The method utilizes the relative difference of directional radiant energy of each directional angle of the directional antenna,introduces Gaussian distribution function and interval mapping technique,adaptively generates the relative direction horn estimator of each rotation angle,and constructs a mixed Gaussian model by accumulating the fusion sub-estimator.The optimal output of the model determines the estimated value of the relative direction angle,enhances the anti-interference ability of the relative direction angle,and improves the accuracy and stability of the accurate estimation of the relative direction angle.The experimental results show that RDAE has a stronger ability to accurately estimate the relative direction angle than the traditional relative direction angle estimation algorithm.Finally,the fusion angle-of-arrival positioning method is further proposed,and the angle estimation and positioning technology based on RDAE is further proposed.(2)RDAE algorithm takes the accurate RSSI relative difference measurement as the core,but the RSSI is susceptible to frequent fluctuations caused by indoor environmental disturbances,and even step changes may occur,making indoor RSSI difficult to accurately estimate.Aiming at this problem,this paper proposes an indoor RSSI adaptive estimation algorithm based on improved strong tracking filter(ISTF)algorithm.The algorithm uses strong tracking filter(STF)to adaptively track RSSI step changes,overcomes the unmodeled dynamics in the traditional RSSI state space model,and uses the sampling process of Gaussian distribution data to analyze the unmodeled uncertain state of the STF algorithm tracking system.Reliability and validity,the strong tracking filter weakening factor is determined,and the moving average filtering algorithm is combined to improve the adaptive estimation ability of RSSI.Compared with the traditional RSSI estimation method,the experimental results show that the proposed algorithm can accurately estimate the indoor RSSI and the convergence speed is faster.(3)Premised on the functional requirements of personnel positioning in the prison factory environment,based on the above ISTF algorithm and RDAE-based angle estimation and positioning technology,based on ZigBee chip CC2530 and protocol stack ZStack,the software and hardware design of wireless positioning node is used,and the stepping motor is used to design a special rotating device capable of rotating the directional antenna.A complete wireless positioning network is constructed,and then the positioning monitoring center software is designed to graphically display the positioning results,thereby establishing a complete wireless positioning system.By simulating the environment of the prison factory in the actual environment,the positioning performance of the wireless system is tested,and the effectiveness and superiority of the proposed algorithm and the positioning system are verified.