Effects of underwater communication constraints on the control of marine robot teams

We address the effects of the aquatic communication channel constraints on the control performances of marine robot teams. The aquatic acoustic channels suffer from significant frequency and distance dependent attenuation, extensive time-varying multipath, motion-induced Doppler distortion and extreme channel latency due to the low speed of sound. Therefore, the available bandwidth is strongly limited and distance dependent. Due to all these limitations, the introduction of intravehicle exchanged information in the control loop of marine robots can degrade the overall system performance. We give an overview of the communication needs in the control of a marine robotic team. A realistic model of the aquatic communication channel is considered, and different limitations of the channel are addressed, e.g., message error rate and communication delays. An overview of the experimental test-bed that is used to study the communication characteristics of the aquatic channel is presented. Finally, we report on an extensive simulation study on the performance of a controller for a marine surface vessel which relies on an acoustic communication channel for information sensed at a distance.