SBIR Phase II: High Resolution Channel Sounding for Indoor TDOA Positioning Using a Narrowband RF Transceiver

这个小企业创新研究二期项目的重点是室内环境的高精度无线定位技术。迄今为止，基于飞行时间的室内定位技术在商业上几乎没有取得成功，主要是因为多路径信号反射会抹掉空中信号的到达时间，使得从视线（LOS）或最短距离路径确定到达时间变得困难。对抗多径的最佳方法是使用带宽超过500mhz的超宽带（UWB）定位信标信号；宽的信号带宽增加了时域分辨率，使接收机能够从其他路径中区分LOS。UWB面临的挑战是制造成本高，直流功耗大，以及限制其范围和工作频率的监管问题。我们研究的重点是开发一种方法来克服这些限制，通过定义一种方法来传输一系列基于相对窄带标准的信号（例如WiFi），使其表现得像超宽带信号，在不增加成本的情况下产生类似超宽带的定位精度，并且没有任何其他上述缺点。该项目的广泛影响和商业潜力部分得益于智能手机的普及，越来越多的应用程序可以从高精度室内定位技术中受益，包括：室内路线指导、移动零售（查找产品、接收定向广告、使用就近分类购物清单）、医疗保健和制造业的员工和资产跟踪、室内E911、基于位置的安全、展览跟踪评论和盲人路线指导。然而，现有的最先进的定位系统，如WiFi接收信号强度（RSS）技术，在许多此类应用中不够精确（通常在90%置信度下为30英尺）。目前，基于UWB的解决方案比RSS更准确，但由于成本、直流功率和监管限制，将UWB集成到智能手机中存在很强的阻力。该项目的目标是提供一种对WiFi芯片组的MAC和PHY进行直接修改的方法，以达到3英尺或更高的室内定位精度，置信度为90%，在不增加成本的情况下产生数量级的精度提高，因为WiFi已经是大多数智能手机的标准功能。

This Small Business Innovation Research Phase II project is focused on high-accuracy wireless positioning technology for indoor environments. Indoor time-of-flight-based positioning technologies have had little commercial success to date primarily because of multipath - signal reflections that smear the arrival time of the over-the-air signals, making it difficult to determine the arrival time from the line-of-sight (LOS) or shortest distance path. The best way to combat multipath is to use ultra-wideband (UWB) location beacon signals with bandwidths in excess of 500 MHz; the wide signal bandwidth increases the resolution in the time-domain, allowing the receiver to distinguish the LOS from other paths. The challenges with UWB are that it is plagued by high manufacturing costs, too much DC power consumption and regulatory issues limiting its range and operating frequencies. The focus of our research is to develop a way to overcome these limitations by defining a method for transmitting a sequence of relatively narrowband standards-based (e.g., WiFi) signals in such a way as to make them behave like UWB signals, yielding UWB-like positioning accuracy at no additional cost and without any of the other aforementioned shortcomings.The broader impact/commercial potential of this project is fueled in part by the ubiquity of the smartphone, whereby a large and growing number of applications could benefit from high-accuracy indoor positioning technology, including: indoor route guidance, mobile retail (find products, receive targeted ads, use proximity-sorted shopping lists), staff and asset tracking for healthcare and manufacturing industries, indoor E911, location-based security, exhibit tracking commentary and route guidance for the blind. However, existing state-of-the-art positioning systems such as WiFi received signal strength (RSS) techniques are not accurate enough (typically 30 feet at 90% confidence) for many of these applications. There are UWB-based solutions available today that are much more accurate than their RSS counterparts, but there is strong resistance to integrating UWB into smartphones due to cost, DC power and regulatory limitations. The goal of this project is to provide a way to make straightforward modifications to a WiFi chipset's MAC and PHY in order to achieve an indoor location accuracy of 3 feet or better with 90% confidence, yielding an order-of-magnitude accuracy improvement at no additional cost, since WiFi is already a standard feature in most smartphones.