A robust acoustic signal for smartphone-based indoor ranging and positioning

The acoustic signal is an important medium in communication, damage andleakage detection, etc., and, in recent years, for use in wireless sensor network positioning.with the development of mobile communication technology, smartphone-based indoorpositioning by acoustic signals becomes possible. in an indoor environment, however,acoustic signals are interfered with by environmental noise and multipath eects. moreover,when multiple users position simultaneously, acoustic signals interfere with each other. inorder to eliminate various forms of interference, in this paper, we design a robust acousticsignal for smartphone-based indoor positioning. the signal is generated using pseudorandomcodes; gold sequences, to modulate a 6 khz cosine wave. it is detected through itsauto-correlation properties in the receiver. the designed acoustic signal can resist variousnoises with its excellent cross-correlation characteristic. we conduct experiments on realsmartphones and the results show that the signals can work well in the presence of formsof interference.