SBIR Phase I: Active Radar Multi-Path Mapping for High-Precision Ranging Applications

这个小型企业创新研究（SBIR）第一阶段项目的更广泛的影响/商业潜力来自于这样一个事实，即现代真实的时间定位服务（RTLS）系统提供了提高仓库，办公室和医院效率的潜力，并在紧急情况下提高第一响应者的安全性。在该项目中开发的高精度射频（RF）测距技术有望实现当前RTLS系统无法实现的新应用领域。预计所提出的技术将提供比使用低成本现成组件的当前最先进系统三个数量级的精度改进，同时还减轻了RF系统的常见技术问题（例如由于多径RF反射导致的性能差）。如果成功开发，所提出的技术可以实现高精度RF测距，用于运动跟踪，准确的室内定位，机器人，高价值资产跟踪，周边安全和准确的第一响应人员跟踪。这个小企业创新研究（SBIR）第一阶段项目研究了在一个新的基于RF的RTLS系统中缓解多径问题的算法。RTLS系统依赖于参与节点之间的鲁棒距离估计。多路径反射是这些测距估计的最重要的误差来源，过去证明很难减少其影响。2.4 GHz窄带无线电的最新发展允许基于载波相位测量的毫米级精确测距技术，类似于差分GPS系统。外部干扰可以通过使用纯载波音调的相位信息和通过在多个离散频率上跳频来“分组化”距离测量来最小化。添加天线阵列和天线之间的快速切换增加了进一步的功能，因为不同的天线相位测量可以组合成可操纵的虚拟天线。这类似于主动雷达系统，除了它是使用低成本的现成组件。通过使用距离信息和虚拟天线角度与不同的多径分量相结合，所提出的系统能够映射RF反射对象，允许更高级别的算法准确地确定房间中设备的位置。所提出的技术提供了一个潜在的精度提高三个数量级，比现有的方法。

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project derives from the fact that modern Real Time Location Service (RTLS) systems offer the potential to improve the efficiency of warehouses, offices, and hospitals, and to increase the safety of first responders during an emergency. The high-precision radio frequency (RF) ranging technology to be developed in this project is expected to enable new application areas that are out-of-reach with current RTLS systems. The proposed technology is expected to provide an accuracy improvement of three orders of magnitude over current state-of-the-art systems using low-cost of-the-shelf components, while also mitigating common technical problems with RF systems (such as poor performance due to multi-path RF reflections). If successfully developed, the proposed technology could enable the use of high-precision RF ranging for motion tracking, accurate indoor localization, robotics, high-value asset tracking, perimeter security, and accurate first-responder person tracking. This Small Business Innovation Research (SBIR) Phase I project investigates algorithms to mitigate multi-path issues in a novel RF-based RTLS system. RTLS systems rely on robust range estimates between participating nodes. Multi-path reflections are the most significant source of error for these ranging estimates, and reducing their effect has in the past proven difficult. Recent developments in narrow-band 2.4 GHz radios allow millimeter-accurate ranging techniques based on carrier-phase measurements, similar to differential GPS systems. External interference can be minimized by using the phase information of pure carrier tones, and "packetizing" the range measurements by hopping over multiple discrete frequencies. Adding an antenna array and fast switching between the antennas adds further capabilities, as the different antenna phase measurements can be combined into a steerable virtual antenna. This is similar to active radar systems, except that it is done using low-cost of-the-shelf components. By using distance information and virtual antenna angle combined with the different multi-path components, the proposed system is able to map RF reflecting objects, allowing higher-level algorithms to accurately pinpoint the location of a device in a room. The proposed technology offers a potential accuracy improvement of three orders of magnitude over existing methods.