Ultrasonic rangefinder with the submillimeter resolution as a part of the rescue robot’s sensor system
S. Goll, J. Maximova
Abstract:
The main goal of the research is to increase the measurement resolution of the ultrasonic range finders to meet the needs of vital signs non-contact registration based on the chest movements. The two-phase method is proposed to make distance estimates by sending the probe pulse trains, calculating the phase spectrum of the echo signal’s envelope and tracking its relevant components. During the first phase the rough TOF based estimate is made. During the second phase this estimate is corrected based on the phase spectrum of the echo signal’s envelope, the phase ambiguity is removed and the relevant components are determined. The final estimate of the human chest displacement is calculated based on these relevant components. The output data rate is the same as for the TOF measurements, but the measurement resolution is increased to the one hundredth of the ultrasonic wavelength. The experiment results are provided for the both model and the real human chest displacements caused by the respiration and heartbeat processes.
