Research And Implementation Of UWB Ranging System Based On TOA Estimation

The sensor network, Internet of Things and Smart Home and some otherinformation technology have developed rapidly and become more closely to people’sdaily life and industrial production in recent years. Distance information is often thebasic factor when these modern information technologies want to provide other services,so ranging is an essential function. Ultra-wideband technology use a nanosecond orsub-nanosecond level narrow pulse as an information carrier, so it has a very high timeresolution, and then it can achieve centimeter-level spatial resolution. It also has a verylow power spectral density and good penetration ability. So, ultra-wideband signalshave many ranging advantages unmatched.Conventional UWB ranging techniques rely on the angle of arrival (AOA),received signal strength (RSS) and time of arrival (TOA) measurements. The techniquebased on the AOA measurement needs to use the antenna array, which will result in thesize of the system, power consumption and cost increase. The technique based on theRSS technique needs an accurate channel model estimate, so ranging accuracy can notbe guaranteed. The technique based on the TOA measurement make good use of theadvantage of a high temporal resolution, so it can get a better ranging accuracy and lowsystem complexity. So in the thesis, the technique based on TOA measurement is chosenwhen UWB ranging system is being developed in hardware platform.There are two methods to achieve the TOA estimate, coherent detection andnon-coherent detection. The traditional coherent detection algorithm and GeneralizedMaximum Likelihood coherent detection algorithm requires high-speed sampling rate,and use a correlation receiver with the received waveform and the template signal,which will result in the high hardware cost and large calculation. Non-coherentdetection algorithms mainly include MES algorithm, TC algorithm and MES-SBalgorithm. Given the characteristics of the hardware platform, the MES algorithm is themost suitable algorithm to achieve the TOA estimation.On the basis of the UWB ranging theory, a UWB ranging system is designed anddeveloped in the hardware platform to achieve a one-way ranging function, two-wayranging function and long-distance two-way ranging function. A large number ofexperiments are performed, and the error statistical results illustrate that the UWBranging system is able to achieve high accuracy ranging. There are three parts of thesystem development, timing circuit design in the FPGA chip, communication functiondesign in the ARM chip and client software on PC.