Self Localization Using A Modulated Acoustic Chirp

This paper describes a robust self localization algorithm implemented on a network of acoustic sensors. The sensors are severely constrained in both power and computational performance. An acoustic ranging technique employing a linear frequency modulated chirp is first used to estimate the range between a pair of nodes. The modulated acoustic chirp provides significant benefits in increased range and the ability to separate direct path and multi-path reflections. Localization was performed in the network using a simple trilateration technique based on the estimated ranges to four known beacons. The resulting algorithm is highly accurate under very difficult conditions including significant multi-path and high levels of background noise. The algorithm was implemented and deployed on prototype hardware and operated in real time under realistic operational conditions.