The big overview is in
codas_docs
UHDAS Technical Documentation
ADCP Data Quality: Calibration
- Bottom Track Calibration of a new installation
Summary
(1) (re)install the instrument, with all attempts to put
"beam 3" at 45deg to starboard. It is not critical
that the angle be exact; ultimately it is critical to
determine the angle accurately, and it is much easier if
we start with a god nominal guess.
(2) If this is a new instrument, the ship configuration needs
to have this new instrument added to its configuration.
Eg. Revelle swapped an NB150 for an OS150. This requires
a configuration change in the code. As part of the change,
the ADCP guru will regenerate "config" and "www".
(3) Run a test cruise at the dock (with the instrument wet)
and verify that the UHDAS Gui tool behaves as expected,
and the pictures come up after 5min (for the profile)
and 20min (for the vector plot (the map)
(4) Before leaving port, start the cruise (suppose it was ZZ1405)
but name it ZZZ1405_calib, because we are going to change
a calibration number and need to start a new cruise for it to
take effect. We might as well identify the first segment
with a reasonable name
- turn on Bottom Track for the instrument we are calibrating
- if this instrument is an Ocean Surveyor, use either
broadband or narrowband, but not both
Once the ship is in water deeper than the range of the
new instrument, turn off bottom track:
- stop logging
- toggle bottom track off
- start logging
(5) Suppose the new instrument is OS150 and we are running
Bottom Track and Narrowband. The calibrations are written to
/home/data/ZZZ1405_calib/proc/os150nb/cal/botmtrk/btcaluv.out
i.e.
/home/data/CCCCCCCCCCC/proc/PPPPPPPPPPPPP/cal/botmtrk/btcaluv.out
cruise name processing dir
The file is updated every 15min, and eventually numbers will start
showing up in this file. Look for the line near the bottom that
begins with the word "phase". The value we need to know is the
median (or mean) phase. We want over 5-10 "edited" bottom track
points, so several hours, if possible.
Suppose the last block looks like this
unedited: 130 points
edited: 117 points, 2.0 min speed, 2.5 max dev
median mean std
amplitude 1.0038 1.0037 0.0032
phase -5.3184 -5.2997 0.2687
We will "apply the bottom track calibration phase of -5.3".
This means we will change the transducer angle by SUBTRACTING
the value we just identified (also see below)
new transducer angle = old transducer angle - (value from bottom track)
new transducer angle = old transducer angle - (-5.3)
new transducer angle = old transducer angle +5.3
(6) Before we edit the code,
- stop logging
- end cruise
- kill UHDAS Gui
(7) Save the original file /home/adcp/config/proc_cfg.py to a
backup name, eg: proc_cfg.py.orig
Open /home/adcp/config/proc_cfg.py in an editor.
Identify the lines that assign the values for "h_align"
eg.
#----- begin python code snippet ------
# heading alignment: nominal - (cal/watertrack)
h_align = dict(
os150 = 45.0,
os75 = 48.2,
)
#----- end python code snippet ------
==> We will replace the number 45.0 (the nominal value for OS150)
with (nominal - bottomtrack), i.e.
45 - (-5.3)
i.e. 48.3
The new code block looks like this (note the added comment)
#----- begin python code snippet ------
# heading alignment: nominal - (cal/watertrack)
h_align = dict(
os150 = 48.2, # 45 - (-5.3) from BT cal Oct 2014
os75 = 48.2,
)
#----- end python code snippet ------
Save and exit.
(8) IF the instrument is an Ocean Surveyor, MAKE SURE the EA value in
/home/adcp/config/sensor_cfg.py is within about 5-10 degrees of
the h_align value above. This line would be fine:
'commands' : ('EA04500',),
(This is irrelevant for Workhorse or Broadband instruments)
(9) Start the new cruise leg
- Open UHDAS Gui tool
- start cruise ZZZ1405
- start logging
Troubleshooting:
- If the UHDAS Gui does not start or the buttons do not work,
you made a typo. Look at these files to determine what the
error might be (look at the last files in /home/adcp/log
with the suffix ".warn" or ".err")
- You should see the profile plot (5-minute plot) in less than 10min
You should see the contour and vector plots (map) in about 20min
And of course, send email if there is a problem
uhdas@hawaii.edu
--------------------------------------------
2015/05/01
