Firefly based distributed synchronization in Wireless Sensor Networks for passive acoustic localization

Abstract

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. If the subject of interest emits a recognizable sound and is picked up by a distributed array of microphones it is possible to measure the difference in arrival times and reconstruct the source positions. This requires the microphones to be synchronized up to a fraction of the expected time differences of arrivals in order for the system to be able to produce accurate location estimates. In this paper we take a closer look at the techniques required to synchronize a network of sensors, connected through a low-power RF-communication link, in a distributed manner, ie. without the presence of a master node.The absence of a master node makes the network more robust against the failure of a single node. We took inspiration from the synchronization technique observed in some species of fireflies. A synchronized pseudo random number is embedded in the captured data as a marker to re-align the data-streams in time in a post-processing stage.

Passive Acoustic Sound Source Tracking in 3D Using Distributed Microphone Arrays

“…As shown in figure 1b an optional antenna can be connected for wireless synchronization between different nodes. The synchronization channel is then recorded as a sixth channel by the ADC [17]. More information on the synchronization method for the sensor array can be found in section II-C.…”

“…In [17] we describe a biologically inspired, distributed synchronization mechanism using pulse-coupled oscillators for clock synchronization in a WSN. By embedding the synchronization data in the recorded data, we can robustly add timing information to a recording.…”