Ultrasonic TDoA Indoor Localization Based on Piezoelectric Micromachined Ultrasonic Transducers

Internet of things applications call for increasingly demanding accuracy of indoor positioning. In this work, piezoelectric micromachined ultrasonic transducer (PMUT) based time difference of arrival (TDoA) indoor positioning technology is proposed. Compared with traditional acoustic positioning technology, the technology features small footprint and easy integration into miniaturized systems. We designed and fabricated a low-frequency PMUT chip for demonstration. At the same time, an ultrasonic coding scheme based on binary phase shift keying (BPSK) was used. Finally, a time difference ranging experiment was carried out, and within a distance of 50cm, the error was at the millimeter level. The experimental results verify the feasibility of applying PMUT to indoor positioning systems.