The Study Of High-resolution Time Delay Estimation And Positioning Technology Based On UWB Signal

Ultra Wideband (UWB) wireless communication technology receives more andmore attentions in recent years since it has advantages of high transmission rate, lowtransmitting power, high multipath resolution and strong anti-interference ability. Inparticular, the UWB high accuracy positioning technology has broad applicationprospects in short distance indoor positioning systems. It makes up for the defect oflow positioning accuracy caused by non-line of sight(NLOS) and multipath intraditional positioning systems such as the global positioning system(GPS).This paper studies the UWB positioning technology and the estimation methodof time delay. According to the different types of parameters measured in thepositioning system, the basic positioning methods can be divided into the followingfour types: Time of Arrival(TOA)、 Angle of Arrival(AOA)、 Received SignalStrength(RSS) and hybrid location method.Using nanosecond pulses as transmission signals, the UWB wireless positioningtechnology has the advantage of high time resolution. The positioning method basedon time of arrival can make full use of this advantage and is the most suitable methodto the UWB positioning system. The time delay estimation is an important technologyin the positioning system based on time of arrival. High resolution time delayestimation is the key to accurate positioning since it directly affects the positioningerror. In order to overcome the influence on the positioning accuracy caused bymultipath and NLOS, high-resolution time delay estimation algorithm is essential.Based on the analysis of the UWB multipath channel model and signal model, theparameter estimation algorithm based on subspace is introduced to the UWBpositioning system to achieve high-resolution time delay estimation in this paper.The main contents and structure are as follows:Based on the analysis of global navigation satellite system (GNSS), Bluetooth,Wi-Fi and other indoor wireless location systems, Chapter1summarizes the advantages of UWB wireless positioning system such as strong anti-interferenceability, high multipath resolution, low transmitting power and makes clear the purposeand significance of this study combining with the domestic and foreign research statusof UWB positioning system.Based on the analysis of basic knowledge of UWB communication, variouspositioning methods are researched and analyzed. Chapter3theoretically proves thatthe positioning method based on the arrival time can make full use of the advantage ofhigh time resolution and improve the positioning accuracy. This chapter makestheoretical preparations for the study of high-resolution time delay estimation methodin the UWB positioning system.As the transmission signal may be affected by multipath, reflection, diffraction,non-line of sight and other factors, the traditional time delay estimation methods havelow precision and cannot achieve accurate positioning.In order to achievehigh-resolution time delay estimation in dense multipath environment, the UWBsignal time delay estimation method is studied further. Based on the research andanalysis of traditional methods such as correlation method and double spectrummethod,the parameter estimation algorithm based on subspace is introduced to theUWB positioning system. Chapter5focuses on the time delay performance of MUSICalgorithm, ESPRIT algorithm and TLS-ESPRIT algorithm. The simulation experimentcarried out in the multipath environment verifies the effectiveness of the algorithmsbased on subspace. Finally, combined with the measurement of the angle, theTLS-ESPRIT algorithm is applied to the UWB single base station positioning systemand better positioning accuracy is obtained.