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

这个小型企业创新研究第二阶段项目的重点是室内环境的高精度无线定位技术。室内基于飞行时间的定位技术迄今为止几乎没有商业上的成功，这主要是因为多径信号反射模糊了空中信号的到达时间，因此很难从视距（LOS）或最短距离路径确定到达时间。对抗多径的最佳方法是使用超宽带（UWB）带宽超过500 MHz的定位信标信号;宽信号带宽提高了时域分辨率，使接收器能够区分LOS和其他路径。UWB面临的挑战是，它受到高制造成本、太多DC功耗以及限制其范围和工作频率的监管问题的困扰。我们研究的重点是开发一种克服这些限制的方法，方法是定义一种用于发送相对窄带的基于标准的序列（例如，WiFi）信号，使其表现得像UWB信号，在没有额外成本和没有任何其他上述缺点的情况下产生类似UWB的定位精度。该项目更广泛的影响/商业潜力部分是由智能手机的普及推动的，因此大量且不断增长的应用可以从高精度室内定位技术中受益，包括：室内路线指引、移动的零售（查找产品、接收有针对性的广告、使用邻近排序的购物清单）、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引。然而，诸如WiFi接收信号强度（RSS）技术的现有技术水平的定位系统对于这些应用中的许多应用而言不够准确（通常在90%置信度下为30英尺）。目前有一些基于UWB的解决方案比RSS解决方案更精确，但由于成本、直流电源和监管限制，将UWB集成到智能手机中存在很大阻力。该项目的目标是提供一种直接修改WiFi芯片组的MAC和PHY的方法，以便在90%的置信度下实现3英尺或更高的室内定位精度，从而在不增加成本的情况下提高精度，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.