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At the moment, none of our cal_files have Vazimuth entries, so everything is in instrument coordinates.  This isn't useful for our users.  We are expecting "exact" angles to be measured using the laser multistations during operations, but until then probably need to do something else.  One complication is that we are using Gills, METEKS, RMYs, and CSATs.  I assume the Gills were all set to have north=north.  We set the METEKS and RMYs to have north=along boom away from the tower, though some may have been opposite(!).  The CSATs are all along the boom, pointing away from the towers.  So, we also need to know the tower orientation.  The booms are nominally parallel to the ridge, pointing in the SE direction.  Call this direction 142degrees.

In one case, I oriented 10m.tse12 antiparallel to the other sonics (boom pointing in the NW direction) to avoid a local tree.

Thus:

Gill: (For Gill R3s, Vaz is the N arrow direction + 240 degrees.)

   vaz = 0 + 240 = 240

CSAT: (For ATI and Campbell CSAT3 sonics, Vaz is the direction relative to true north, straight into the array from the un-obstructed direction, minus 90 degrees.)

   vaz = 142+180-90 = 232

CSAT.10m.tse12: vaz = 142 - 90 = 52

RMY: (from me: +v is "from north", oriented perpendicular out from the connection box.  Assuming we mounted the box away from the tower, this is the boom direction away from the tower:)

  vaz = 142 (it seems that 142+180 works better – perhaps we put the connection box towards the tower?)

METEK: (from me: manual seems to show +v is perpendicular to N arrow – essentially East)

  vaz = 142 + 90 = 232 (sign convention appears to be left-handed.  we'll change this in NIDAS.  Also, this makes vaz = 232-180 = 52)

All this now implemented in cal_files and config.

 

 

1 Comment

  1. Steven Oncley AUTHOR

    My assumption about the Gill Windmaster Pros was wrong, and our wind direction quick reference also does not apply to the Windmasters.  These were mounted with the North arrow pointing to the tower, along the boom.  The coordinate system is right-handed, with vaz 90 degrees counterclockwise from the North arrow.  Thus, for a nominal boom direction of 142, into the tower would be 322 and 90 degrees counterclockwise would be 232.  Coincidentally, this is pretty close to the 240 that I assumed above, which is why I became confused.  As of this writing, we now have DTU's laser scans of all of these boom angles, so we can put the exact values into the cal_files.