24GHz FMCW Radar Indoors Mobile

We use AncorTek’s SDR-KIT 2400AD2, a low-power and compact software-defined radar for FMCW-based sensing, sitting at the top deck of the prototype mobile node. The center frequency of transmitted signal is adjustable within the 24-26 GHz frequency band. AncorTek provides drivers only for Windows, and thus, we use a Windows laptop to receive and store the complex in-phase and quadrature (I/Q) components of the received FMCW radar signal in a .dat file. Maximum allowed duration using the AncorTek software is 10 minutes and thus the length of a single experiment is 10 minutes. For the AncorTek radar’s operation settings, we choose a bandwidth of 2 GHz at a center frequency 25 GHz during all our experiments. Each chirp is of 1 ms duration with 128 samples per chirp. With these settings, the range resolution and the maximum range that can be measured are 0.075 m and 4.8 m, respectively. Also, the maximum radial velocity that can be measured is 3 m/s. The radial velocity resolution is dependent on the number of chirps processed together at once for one frame. Lastly, we also track the mobile node with the help of OptiTrack Motion capture system that collects the position and orientation of the mobile node in to provide a csv file for each experiment.

本研究采用AncorTek公司的SDR-KIT 2400AD2，这是一款面向调频连续波（Frequency-Modulated Continuous-Wave，简称FMCW）传感应用的低功耗紧凑型软件定义雷达，搭载于原型移动节点的顶部区域。其发射信号的中心频率可在24~26 GHz频段内调节。由于AncorTek仅提供适用于Windows系统的驱动程序，因此本研究采用Windows笔记本电脑接收并存储接收到的FMCW雷达信号的同相正交（In-phase and Quadrature，简称I/Q）复分量，并保存为.dat格式文件。AncorTek官方软件单次允许的最长采集时长为10分钟，因此单次实验的时长设定为10分钟。在所有实验中，我们将该雷达的工作参数设置为：中心频率25 GHz，带宽2 GHz。每个线性调频脉冲（chirp）的持续时长为1毫秒，每个脉冲包含128个采样点。基于上述参数，该雷达的距离分辨率与最大可测距离分别为0.075 m与4.8 m，最大可测径向速度为3 m/s。径向速度分辨率取决于单帧内同时处理的线性调频脉冲总数。此外，本研究还借助OptiTrack动作捕捉系统（OptiTrack Motion Capture System）对移动节点进行追踪，该系统可采集移动节点的位置与姿态信息，并为每次实验生成逗号分隔值（Comma-Separated Values，简称CSV）格式文件。