Passive Acoustic Localization Based on COTS Mobile Devices

Passive acoustic localization is an important technique in a wide variety of monitoring applications, ranging from healthcare over biological survey to structural health monitoring of buildings. However, the method obtains the location of an unknown sound source with low-cost and simple still is lacking. In this paper, we implement a passive sound source location system based on commercial off-the-shelf (COTS) mobile devices, typically a smartphone, are organized as Wireless Sensor Networks (WSNs). We use the Precise Time Protocol (PTP) in WLAN to achieve the time synchronization of mobile devices with a coarse grain, and then uses moving variance and linear interpolation to get the Time of Arrival (TOA) of the sound source signal. We also design and implement a robust Sequence-Based localization algorithm based on Linear Programming, i.e. LPSBL, which transforms the TOA information of the sound source signal arriving at these devices to a nodes sequence and estimate the location of the sound source by the nodes sequence. After plenty of experiments were carried out, it is verified that our system can provide sufficiently reasonable positioning accuracy and good robustness in an indoor environment.