Doppler Velocity Log for ROV Tunnel Inspection

At the Teledyne Marine Technology Workshop in San Diego in October 2015 a presentation featured the integration of several technologies to support inspection of a hydro-electric powerplant tunnel using a Saab Seaeye Falcon Remotely Operated Vehicle (ROV) by Vocean Limited (UK).

To locate the ROV in the tunnel the usual method is to accurately measure the payout length of the ROV tether. Due to the complexity of the tunnel system requiring inspection, an alternate method of using a Teledyne RDI Explorer DVL was proposed. The DVL was successfully integrated into the Falcon together with a blue/green laser sensor that was used to measure the depth of damage in the tunnel.

The inspection demonstrated that a DVL could be integrated into a small inspection ROV such as the Falcon. Data acquisition was managed with the WinRiver II discharge acquisition software. This software is normally used in river discharge applications, however, it also has the capability to decode the RDI Explorer DVL format.

The DVL is mounted with a simple adaptation plate on the side of the Seaeye Falcon ROV

The DVL must be mounted and aligned perfectly level with the ROV