Improved underwater acoustic communication for AUVs

The results of an R&D project on acoustic communication algorithms are presented, together with a design for advanced acoustic communication systems for autonomous underwater vehicles (AUVs). Results from tests in data coding indicate that convolutional data codes that provide an increase in data rate and a reduction in signal energy relative to diversity 4 can be used to combat signal fading. Equalization results provide a baseline for future work to enhance equalization performance in the ocean environment. Synchronization efforts to date have produced an approach to synchronization for underwater acoustics using an extended Kalman filter to incorporate an estimate of the channel impulse response into the synchronization process. The experience gained from this activity has been used to perform the system design of an acoustic communication system for AUVs that can reliably operate at ranges up to 2000 yards at data rates of 1200-4800 bps