Research And Implementation Of TC-OFDM Indoor Positioning Singal Networking And Time Synchronization

With concepts such as Internet of Things and Smart City put forward,the Location Based Service has been widely incorporated into people's daily life.But the current GNSS can not effectively cover in high buildings and urban canyon,positioning accuracy can not be guaranteed.In order to achieve indoor and outdoor high-precision seamless positioning,Time&Code Division-Orthogonal Frequency Division Multiplexing(TC-OFDM)outdoor base stations and indoor supplement system is used to complement GNSS system coverage range.In order to realize wide-area indoor and outdoor high-precision seamless positioning,the problem of synchronization networking coverage using space indoor positioning signals in complex buildings and the outdoor coverage of the TC-OFDM signal should be solved.This paper focuses on the outdoor base station coverage of TC-OFDM indoor positioning system based on terrestrial broadcast network and the time synchronization of indoor supplementary system and the time synchronization networking between indoor supplementary systems.A multi-level network based on ultra-wideband(UWB)and time synchronization technology based on UWB bidirectional alignment are proposed.And conduct feasibility verification analysis.The main research contents and results are as follows:1)Based on the study of wireless signal propagation model theory,collecting and analyzing the signal of TC-OFDM outdoor base station,the Okumura-Hata model calibration model has been proposed.According to this model,a TC-OFDM signal coverage model is established.The traditional wireless signal propagation model is analyzed by collected base station signals,the obtained Okumura-Hata model has small prediction error.The Okumura-Hata calibration model with correction factor is obtained by nonlinear least square method,Compared with the Okumura-Hata model,the prediction accuracy is improved 2-3 dB.2)Based on indoor positioning signal network theory,the networking modes of several indoor supplementary systems are analyzed and compared,and the UWB hierarchical network model is studied.The scheme of indoor supplement system using UWB networking is put forward to solve the problem of indoor positioning signal network limited by the constraints of indoor building space;3)The method of time synchronization between satellite and terrestrial in traditional satellite navigation system is analyzed and studied.For the problem of the short distance between the indoor positioning synchronization nodes and high synchronization precision requirements,a bidirectional synchronization method based on UWB signals is designed.And the feasibility and error analysis of this technique applied to the time synchronization of TC-OFDM indoor positioning signals are analyzed.Theoretical and experimental simulation shows that the synchronization accuracy can reach 2ns;...