DVL mounting considerations for ROVs and AUVs

When deploying the Syrinx DVL, the following guidelines should be used to determine where and how the Doppler velocity log (DVL) is mounted for optimal performance.

1. The Syrinx DVL requires clear line of sight below the vehicle on which it is mounted (for conventional downward-facing mounting arrangements).
This includes 15° clearance around the direction that is orthogonal to the transducer face. The transducer face is orientated at 30° azimuth from the vertical (downward) direction, with each beam at a 90° offset in yaw respective to one another, and all beams rotated 45 degrees in yaw from the forward mark.

2. The Syrinx DVL should be mounted at the greatest distance possible away from the seabed (taking into account Step 1 above).

a. This is to offset the minimum altitude of operation of the Syrinx DVL of <0.4 m.

b. If the Syrinx DVL can be mounted 0.4 m or greater above the bottom of the vehicle with clear line of sight, bottom lock should rarely be lost even if the vehicle settles on the seabed.

3. For optimal tracking performance, care should be taken not to mount the Syrinx DVL above thruster outtakes or other sources of turbulent water.

4. The Syrinx DVL is deployed with the interface plate and isolation plate attached to electrically isolate the device from the vehicle, however the electrical isolation is not a necessity.

5. The orientation of the Syrinx DVL is also important and can affect performance in certain scenarios.

a. For most operations, the desired orientation is to line up the Syrinx DVL forward mark (label or machined grove on housing) with the forward heading of the vehicle.

b. For following pipelines where altitude measurements above the pipe are very important, the Syrinx DVL can be rotated by 45 degrees so that beams then face forward, aft, port and starboard rather than inter-cardinal directions. This will result in the forward and aft beams being directed onto the pipe surface.

c. If the Syrinx DVL is mounted at a known angle offset, ensure that the correct offsets are applied for yaw, pitch and roll either in the Syrinx DVL or the navigation software to ensure velocities are used in the correct direction.

Contact Support@sonardyne.com for more information.