The project develops a high data rate optical communication system and a localization algorithm that combines optical with acoustic information as well as two robot capabilities that use the optical communication system. The first explores new methods for acoustic and optical underwater coordination that lead to target identification and efficient data muling using autonomous underwater vehicles. The second explores the use of optical communication as a remote control of an underwater robot as well as for live video transmission from the robot.
The systems contribute a new approach to search and rescue at sea and also enhance the tools available to marine sciences. The proposed underwater systems enhance the scope of observations and communication of the ocean?s physical properties which are essential for advancing knowledge on a wide variety of multi-disciplinary, societally-relevant concerns such as climate variability, gaseous sequestration (e.g., CO2), biogeochemical cycles, and ecosystem dynamics for small scale (e.g., phytoplankton) to large scale (e.g., mammals and commercial fisheries) biota. Furthermore, there is an international collaboration with Prof Hirose from the Tokyo Institute of Technology (TIT) to create an optically-enabled version of AnchorDiver III and demonstrate its ability to localize, communicate, and transmit video imaging. This involves student and faculty exchanges in the international research community.
The goal of this project has been to develop underwater communication technologies in support of the vision to create an underwater observatory, with versatile and easily deployable underwater robots and sensor networks that can: (1) collect effectively the right data; (2) store efficiently the data; and (3) provide quasi-real-time access to it. More than 70% of our planet is covered by water. It is widely believed that the underwater world holds ideas and resources that will fuel much of the next generation of science and business. However, current underwater operations are fraught with difficulty due to the absence of an easy way to collect and monitor data. Underwater sensors exist but they are not networked and their use has many issues: Deploying, retrieving, and using the sensors is labor intensive; Cameras and video cameras are rarely used as sensors; Collecting the data is subject to very long delays; The manual aspects of using the sensors leads to error; Sensors have limited lifetime and there are few recharging options available underwater. What is required is a low-cost, versatile, high-quality, easily deployable platform for underwater communication that will speed-up access to data collected underwater, provide optical feedback underwater, be energy efficient, be easy to use Among these key issues, this project focused on the problem of high-data-rate optical underwater communication. We developed an underwater wireless communication device called AquaOptical, which uses visible light to transmit data at rates of up to 8 Mbps. We investigated ways to maintain these data rates while maximizing our communication range. In particular, we focused on minimizing the requirement for pointing of the transmitter and receiver at each other. This simplies establishing and maintaining communication links. Further, we focused on a device that is practical, i.e., that can be constructed and deployed at a reasonable cost. This requires a careful choice of components, attention to form factors and power consumption, and the development of low-complexity communication algorithms that can be implemented within the hardware constraints of the system. In order to allow easy experimentation with different communication codes and protocols, we developed the optical modem to work as a software defined radio. This also allows the system to adapt to the environment by easily changing its coding. The project enabled international collaborations with Prof Shigeo Hirose (The Tokyo Institute of Technology) and Prof Mandar Chitre (National University of Singapore.) The project supproted the organization of an international workshop on Underwater Robotics (Body, Brain, and Applications) in Singapore on January 16 2012. The workshop web page is available at { t groups.csail.mit.edu/drl/singapore2012}. The goal of the workshop was to bring together a small group of researchers interested in robotics for search and rescue and marine applications. We organized 4 sessions: hardware (body), computation (brain), applications, and discussion on need and impact. Each session was seeded with several presentations followed by discussion. We had domain experts (Roger Payne and Matthias Hoffmann-Kuhnt for the marine side) and Minoru Yoshida (CEO, Hakusan Corporation on the search and rescue side) to help ground the last session. We also had several experts in underwater robotics and communications. In summary, the key outcomes of this project have been the design of a device and algorithms for high-bandwidth point-to-point optical communication in water; an end-to-end model of signal strength in underwater optical communication, along with an experimental evaluation of the model; a novel device for underwater communication with high data rates called AquaOptical II modem; field experiments to evaluate and demonstrate AquaOptical II an international collaborative workshop on underwater technologies
