A 2.67 µJ per Measurement FMCW Ultrasound Rangefinder System for the Exploration of Enclosed Environments

This letter presents the design and experimental characterization of an ultrasound rangefinder system. A new distance measurement method is proposed for determining the relative position among sensor nodes that are operated in a collision and multipath rich environment, while needing no common time reference between them. A 65 nm CMOS technology has been used to build the sensor nodes, which comprise an on-chip receiver and transmitter. The proposed rangefinder system is characterized up to 1 m in air and has a range resolution of 6.5 mm, while dissipating 2.67~\mu {\mathrm{ J}} per measurement.