Aquadopp Tilt

I have recently downloaded an aquadopp 400 kHz profiler that was located in 70 m.  However, on viewing the data files I have found that the meter frame was tilted with the meter recording a pitch of 37 and roll 40.  Velocity data recorded by the meter is excessive for the site, which I assume is due to the excessive tilt.  Can this data be processed to take account of the tilt and give a more representative account of the current profile .

Sorry to hear that the profiler was tilted during data collection....

The answer to the questions is both yes and no.  Yes, you can convert the data back to XYZ coordinates if the system has not been moving around too much. In this sense you can retrieve the original data. The problem is that the tilt sensor will not show values larger than 35-50 degrees (depends on exact sensor) so you don't know how to correctly transform to ENU coordinates.  There are some tricks you can do to get a rough estimate -- for example you can try to find out what pitch/roll gives you zero mean vertical current -- but there are limits to how far you can push it.  The problem in this case is that the beam mapping falls apart for very large tilts. For example, a system tilted by 65 degrees will have at least one beam in the horizontal plane.  In this case you really have no vertical profile at all so there is really nothing to restore.

I hope it works out better the next time!

Best regards,

Atle Lohrmann