Marco BLOCK-BERLITZ | Benjamin GEHMLICH | Michael BOMMHARDT-RICHTER | Hilmar BOCHMANN
(HTW Dresden, Dresden, Germany)
Keywords: underwater archaeologie, UUV, wireless communication, inteligent buoy
“Manio” is our unmanned underwater vehicle (UUV), a customized design based on the BlueROV 2 from BlueRobotics. It can be controlled via a cable of up to ten kilometers in length, although 300 meters have proven to be enough for regular use. This is a standard issue by the manufacturer. The UUV has a large number of sensors, such as an inertial measurement unit (IMU) and a forward-looking camera. The latter streams images in real time to a computer at the base station, allowing the pilot to see exactly what is in front of the UUV. To accommodate for different documentation areas and environments, different side arms have been developed with flexible camera and lighting setups. It is possible, e.g., to use possible to use a variety of action cams with variable stereo overlap. A quick-clamping system is used for fast swap of arms. Another important modification is to leave out the control cable. This is achieved by using a buoy to communicate with the UUV. Inside the buoy, we have a Rocket Prism Gen2, outfitted with two omnidirectional antennas. The orthogonal antenna alignment causes the radio waves to propagate in parallel through the water, allowing for long communication distance. The buoy’s power supply is based on a common 5.000 mAh LiPo battery with three cells and a service time of up to four hours. The base station is placed close to the water, with a directional antenna orientated in the direction of the buoy. This wireless system can communicate across a distance of up to one kilometer. The power supply of the Nano Beam Gen2 is similar to that of the Rocket Prism Gen2, making this a flexible and convenient setup. The problem of underwater localization is addressed by another video live stream from the UUV. This makes use of the GoPro’s integrated wireless module and USB WiFi antenna connected to the UUV’s on-board computer. Because WiFi reach is extremely limited under water, both antennas must be placed very close to each other. Our solution is to extend the UUV’s antenna with an antenna cable and place it directly onto the GoPro’s case.