A Spectrum-Efficient FSK Radar Technology for Range Tracking of Both Moving and Stationary Human Subjects

This article presents a spectrum-efficient frequency-shift keying (FSK) radar technology for Doppler frequency-based moving targets tracking and vital signs (i.e., respiration and heartbeat) based stationary human subject range detection. Fundamental theories of range tracking of linearly moving and periodically moving targets are explained. Different phase extraction methods are categorized and analyzed based on the applicable motion types. The advantage(s), disadvantage(s), and range tracking performance of these methods are compared and summarized. In addition, special conditions and limitations of the different phase extraction techniques are studied. Moreover, range tracking of multiple targets moving in opposite directions and moving in the same direction is investigated. Range detection of a stationary human subject with different orientations relative to the radar line of sight is evaluated. The detection robustness and consistency are explored by measuring a periodically moving small corner reflector at various locations relative to the radar.