| In recent years,with the rapid development of subway construction,the safety of subway tunnel construction has become a hot issue,the real-time monitoring of subway tunnel site construction,especially the construction personnel location information,to reduce the accident loss has a very important significance.However,there still remain some problems,such as short transmission distance,poor Anti-multipath effect,high power consumption and low positioning accuracy,in view of these problems,the paper analyzes the methods and algorithms,selecting the TOA/TDOA method applied to the UWB positioning system,the localization method of tunnel positioning is studied,this paper designs a kind of subway tunnel personnel positioning system based on Impulse Radio-Ultra Wideband,to achieve the positioning of the low-power tag and positioning accuracy requirements.The main contents of this paper are as follows:(1)Based on the basic principles of UWB technology,introducing definition of UWB,the realization of the UWB signal and the features and applications of UWB,by discussing other indoor positioning technology,to illustrate the positioning advantages of UWB Technology;According to several commonly used indoor positioning methods,mainly analyzing the principle and mathematical model of each method,combined with the characteristics of UWB technology,the positioning method suitable for UWB positioning system is obtained.On this basis,combined with the characteristics of the tunnel environment,the Symmetric Double-Sided Two-Way Ranging algorithm based on TOA method is adopted in this paper,and the accuracy of the algorithm is demonstrated.(2)Several classical localization algorithms are discussed,including the least square method,the Fang algorithm,the Chan algorithm,the Taylor algorithm and the Kalman filter algorithm,and the theoretical derivation and simulation analysis are carried out,indicating their respective strengths and weaknesses,combined with the characteristics of tunnel positioning,the accuracy of these classical algorithms is compared,selection of Biased Kalman filter and Extended Kalman filter to meet the requirements of tunneling personnel.Taking into account the limited number of base stations that can be arranged in the tunnel,needing to use very few base stations to achieve high-precision positioning,therefore,this paper presents a low complexity selfchecking triangulation algorithm,the algorithm can utilize two base station real personnel positioning,meeting the tunneling requirements.(3)Aiming at the tunnel location environment,proposed a multi-combinatorial localization algorithm.The algorithm: in order to further improve the positioning accuracy of the algorithm,according to the characteristics of tunnel construction environment,the non-line-of-sight error in the distance measurement process is optimized by using Biased Kalman filter,and then uses Self-checking triangulation algorithm to estimate the position of the target node,and Extended Kalman filter is used to locate the tracking and get the high precision positioning of the tunnel personnel,finally,the positioning accuracy of the positioning algorithm is verified by simulation analysis.(4)The realization of the UWB positioning system,the first is the realization of the overall architecture of the system,including the composition of the system and the realization of the host computer.Then from the hardware on the system base station and tag card of each module are analyzed,and design the circuit principle diagram of each module,from the software introduced in detail the software structure of the system and the specific process of ranging communication,and from the two aspects of the system hardware and software to achieve the low power consumption of the tag card.Finally,the performance of the system is tested and analyzed,mainly from the ranging positioning,coordinate positioning and low power consumption in three aspects of testing,verifying the feasibility of tunnel personnel positioning system based on UWB technology. |
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