Combined vehicle control, status check and high-resolution acoustic images retrieval using a high-frequency acoustic modem on a hovering AUV

Hermes is a two-way half-duplex underwater acoustic modem developed to transfer large amounts of information from an underwater asset to a surface operator, while being able to send command-and-control information to the underwater asset. In addition, this communication system must operate in very challenging environments such as busy ports and very shallow waters. Hermes must also provide the ability to transfer data from multiple sources simultaneously, without any impact on the source of information. To do so, the communication system uses a specific pipe architecture tailored for wireless underwater applications, combined with a multi-scale, parallel decision-feedback-equalizer technique. The authors show that Hermes can relay simultaneously and reliably high-resolution scan sonar images with target recognition, mosaics and vehicle status in various port environments, at a range of up to 130 m using high-frequency, omni-directional transducers. The fastest data rate tested is 87,768 bps. The main platform is the Bluefin Robotics HULS3. Experimental results are also presented using the WHOI Remus-100 Gudgeon.