摘  要

随着无线通信技术的发展和物联网的普及，基于位置的服务(LBS)在现实生活中的应用越来越广泛，人们对LBS的精度要求也越来越高。全球定位系统GPS在开阔室外环境下提供人们精确的位置信息，极大地方便了人们的生活，但是在遮挡物多、建筑物密集的环境下定位精度很不理想，无法满足人们对近距离复杂环境下的定位需求，因此，如何在近距离复杂环境下实现高精度定位成为了研究重点。随着超宽带通信技术的提出和发展，相比较其他无线通信技术，超宽带(UWB)技术具有较强的抗多径能力、穿透力以及很高的定位精度，因此被广泛应用于高精度近距离无线定位系统。

本文首先分析了无线定位的基本原理、常用的定位算法、定位误差的主要来源以及定位系统的定位精度评定标准。通过对常用TDOA方法的分析，基于常用TDOA方法具有锚节点时钟精确同步难、适用性低等局限性，提出一种消除锚节点时钟频率偏差影响的改进被动式TDOA方法，无需进行锚节点时钟精确同步，测量误差只与标签节点的时钟频率有关，并针对于测量误差进行了仿真分析，确定了改进TDOA方法的可行性。本文对超宽带定位系统整体方案进行设计，设计并实现了系统硬件模块。基于对无线定位基本原理的分析以及超宽带时间分辨率极高的特点，本文在系统硬件上分别设计并实现基于到达时间以及基于到达时间差的超宽带定位系统。在基于TOA的超宽带定位系统设计与实现中，通过对基于超宽带技术的几种测距方式的阐述分析，选用了适用于本文系统硬件且误差小的对称双边双向测距法，提出基于时分复用技术的时分TOA超宽带定位系统通信时序的概念，并在本文设计的系统硬件上实现，选用并实现了基于TOA的牛顿迭代定位算法，在室内和室外两种环境下分别进行定点测试、直线测试和曲线测试，对实验结果进行分析。在基于改进TDOA方法的超宽带定位系统设计与实现中，对在本文系统硬件上实现改进TDOA方法的性能进行了分析，提出一种链式TDOA超宽带定位系统通信时序的概念，并在本文系统硬件上实现，选用并实现了基于TDOA的扩展卡尔曼滤波算法对标签节点进行坐标位置估计，在室内和室外两种环境下分别进行定点测试、直线测试和曲线测试，对实验结果进行分析。

关键词：超宽带，定位，到达时间，到达时间差，定位算法

ABSTRACT

With the development of wireless communication technology and the popularity of the Internet of Things(IoT), location-based services (LBS) are becoming more and more widely used in real life, and people's requirements for LBS are getting higher and higher. Global Positioning System GPS provides people with accurate location information in an open outdoor environment, which greatly facilitates people's lives. However, in the environment with many obstructions and dense buildings, the positioning accuracy is not ideal and can not satisfy people's complex environment. The positioning requirements underneath, therefore, how to achieve high-precision positioning in a close-range complex environment has become the focus of research. With the introduction and development of ultra-wideband communication technology, UWB technology is widely used for high precision compared with other wireless communication technologies, such as strong multi-band capability, penetrating power and high positioning accuracy. Short-range wireless positioning system.

This paper first analyzes the basic principles of wireless positioning, commonly used positioning algorithms, the main source of positioning error and the positioning accuracy evaluation standard of the positioning system. Based on the analysis of common TDOA methods, based on the common TDOA method, it has the limitations of accurate synchronization of anchor node clock and low applicability. An improved passive TDOA method for eliminating the influence of anchor node clock frequency deviation is proposed, without the need to accurately synchronize the anchor node clock. The measurement error is only related to the clock frequency of the tag node, and the simulation analysis is carried out for the measurement error, and the feasibility of the improved TDOA method is determined. In this paper, the overall scheme of UWB positioning system is designed, and the system hardware module is designed and implemented. Based on the analysis of the basic principles of wireless positioning and the extremely high time resolution of ultra-wideband, this paper designs and implements an ultra-wideband positioning system based on arrival time and time difference based on the system hardware. In the design and implementation of TOA-based UWB positioning system, through the analysis and analysis of several Ranging methods based on UWB technology, a symmetric bilateral bidirectional ranging method suitable for the system hardware and small error is selected, which is based on time division. The concept of communication timing of TOA ultra-wideband positioning system based on multiplexing technology is implemented on the system hardware designed in this paper. The Newton iterative localization algorithm based on TOA is selected and implemented, and fixed-point test is performed in indoor and outdoor environments. Straight line test and curve test to analyze the experimental results. In the design and implementation of the ultra-wideband positioning system based on the improved TDOA method, the performance of the improved TDOA method on the system hardware is analyzed. The concept of the chain TDOA ultra-wideband positioning system communication timing is proposed. On the hardware implementation, the extended Kalman filter algorithm based on TDOA is selected and implemented to estimate the coordinate position of the tag nodes. The fixed point test, the straight line test and the curve test are carried out in indoor and outdoor environments respectively, and the experimental results are analyzed.

Keywords: UWB, positioning, TOA, TDOA, localization algorithm