基于UWB技术的TDOA定位算法的研究与实现

发布时间：2018-08-11 13:48

【摘要】：随着信息技术的发展,如今人们对空间位置信息的需求越来越依赖。而对于空间位置的定位技术有很多,比如:超声波定位技术、RFID(射频识别)定位技术、Bluetooth定位技术、WiFi定位技术、ZigBee定位技术和超宽带定位技术等。随之也产生众多的定位算法:RSSI定位算法、AOA定位算法、TOA定位算法和TDOA定位算法等。这些定位技术的介绍及优缺点在本文的第二章中做了简略的介绍,而上述的定位算法在本文的第三章中也做了介绍和对比,所以就不在这一一介绍了。可见定位技术的发展之迅速,这也表明了人们对位置定位的需求之大。本文将对超宽带定位系统常用的TDOA定位算法进行研究及实现。TDOA定位算法其实就是使用各基站接收信号的时间之差进行定位的。通常我们得到基站接收信号的时间,也就确定了信号源到基站的距离,再根据信号源到各基站的距离为半径画圆,各圆之间的交点就是信号源的位置。由于绝对时间一般不容易测得,可以通过信号到达基站的时间差,以基站为焦点建立双曲线,到达时间差乘光速就是两基站到信号源的距离差,则信号源在该双曲线上的点,多个双曲线的交点即为信号源位置,这也就是双曲线数学模型。本文首先对超宽带定位技术的国内外发展状况做了大概的了解,并对其知识理论进行了学习和理解,常用的定位性能指标也作了简单的介绍。然后,是对本章主要的内容TDOA定位算法的理论知识和数学模型进行了深度的研究,并对TDOA定位算法需要的基站之间的时钟同步进行了研究,提出一种基于卡尔曼滤波算法的无线时钟同步算法,建立了对应的数学模型,经过仿真实验结果表明基站之间在卡尔曼滤波算法的跟踪作用下,基站之间的时钟同步效果很好。最后,对TDOA定位算法得出的非线性方程求解。介绍了两种常用的经典位置估计算法:Fang算法和Chan算法。并分别进行了仿真实验,结果表明Chan算法效果要比Fang算法好。由于Fang算法不能利用多余的基站信息进行估算,而Chan算法可以利用多余的冗余信息进行估算,所以Chan算法可以通过增加基站来提高定位精度。仿真实验结果也表明了 Chan算法通过增加基站数目来提高定位精度是有限的,当基站数目达到一定数目时,定位精度的改善并不明显。所以Chan算法在实际工程应用中对基站数目的需求视情况而定。
[Abstract]:With the development of information technology, people depend more and more on spatial location information. For example, ultrasonic positioning technology RFID (Radio Frequency Identification) positioning technology Bluetooth positioning technology WiFi positioning technology ZigBee positioning technology and ultra-wideband positioning technology and so on. As a result, there are many algorithms, such as TDOA and TDOA, and so on. The introduction of these localization techniques and their advantages and disadvantages are briefly introduced in the second chapter of this paper, and the above algorithms are also introduced and compared in the third chapter of this paper, so they are not introduced one by one. Therefore, the rapid development of positioning technology also shows the great demand for location. In this paper, we will study and implement the TDOA localization algorithm, which is commonly used in UWB positioning system. In fact, the location algorithm is based on the difference of time between the received signals of each base station. Usually we get the time when the base station receives the signal, and then determine the distance from the signal source to the base station, then draw a circle according to the distance between the signal source and the base station, and the intersection point between the two circles is the position of the signal source. Because the absolute time is generally not easy to measure, the time difference between the signal and the base station can be measured. Taking the base station as the focus, the hyperbolic curve is established. The time difference of arrival multiplied by the speed of light is the distance difference between the two base stations and the signal source, then the point on the hyperbolic curve of the signal source. The intersection point of several hyperbolas is the position of the signal source, which is the hyperbolic mathematical model. In this paper, the development of UWB positioning technology at home and abroad is discussed, and its knowledge theory is studied and understood. The commonly used positioning performance index is also introduced briefly. Then, the theoretical knowledge and mathematical model of the main content of the TDOA localization algorithm in this chapter are studied in depth, and the clock synchronization between the base stations required by the TDOA localization algorithm is also studied. A wireless clock synchronization algorithm based on Kalman filtering algorithm is proposed and the corresponding mathematical model is established. The simulation results show that the synchronization effect between base stations is very good under the Kalman filtering algorithm. Finally, the nonlinear equations obtained by TDOA localization algorithm are solved. In this paper, two classical position estimation algorithms, called: Fang algorithm and Chan algorithm, are introduced. The simulation results show that Chan algorithm is more effective than Fang algorithm. Because the Fang algorithm can not use the redundant base station information to estimate, and the Chan algorithm can use the redundant information to estimate, so the Chan algorithm can improve the location accuracy by adding the base station. The simulation results also show that the Chan algorithm can improve the location accuracy by increasing the number of base stations, but when the number of base stations reaches a certain number, the improvement of location accuracy is not obvious. Therefore, the demand for the number of base stations in practical engineering applications of Chan algorithm depends on the situation.
【学位授予单位】：海南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN925

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