Stop Recorder Deployment
Select
Stop Recorder Deployment
. When data acquisition has stopped a
dialog will display the current AWAC and PC clock time.
Data Retrieval
Select
Recorder Data Retrieval
.
The recorder overview dialog will show a list of all files currently stored in the
recorder, including the time of the first measurement and the size for each
file.
Select a file in the list by clicking on the filename. Press
Retrieve
to specify
the name and disk location of the file.
For systems with a ProLog recorder, you may save time by swapping out the
SD card and inserting it into a memory card reader connected to a PC, as
opposed to downloading data.
Data Conversion
To convert binary data files retrieved from the recorder to a readable ASCII
format, select
Data Conversion
.
Add files to the Files to convert list by using the
Add file...
file selection
dialog. Select the file to convert in the list and press the blue arrow. Specify
the location for the converted files in the Save in folder field. An optional pre-
or postfix that will be added to the recorder filename may be specified. Select
from the View files
drop-down list to open the converted (ASCII) files in e.g.
Notepad.
On-line Data Collection
Select
Start Data Collection
from the On-line menu (or press the toolbar
button) to start data acquisition. The real time display shows velocity data
and sensor data as it is collected.
To capture the data that comes in over the serial port to disk select
Disk
Recording…
from the On-line menu and define the name of a file (without
extension). Once this disk file is defined, the Start Disk Recording and Stop
Disk Recording menu items and toolbar buttons will be enabled.
The output can either be in ASCII, in fixed NMEA format, or binary format.
Note: To output NMEA, use the Activate Serial Output option in the
Deployment planning (need a ProLog installed)
ProLog
The Nortek Processor and Logger (ProLog) is a micro-computer with a 4GB
recorder located on a separate circuit board inside the AWAC. Its primary
function is to reduce raw wave data to standard wave estimates for online
applications. Reduction of wave data is valuable when considering low
bandwidth communications (e.g. acoustic modems, satellite). To learn more
about the ProLog option visit the website.
Mounting
Proper mounting of the instrument is crucial for successful collection of data.
Please mount the instrument in accordance with the
Mounting Guidelines
.
Tip! Check the retrieved data before deploying the instrument for the second
time. If something is wrong with the instrument, the configuration or the
deployment, this will be detected and the possibility of making the same mistake
twice is avoided.
Basic principles
The AWAC measures
current speed and direction
by transmitting sound waves
that are reflected by particles
drifting with the currents in
the water. The Doppler shift
of the return signal is
proportional to the velocity
component along the beams.
By combining the Doppler
shifts from the three beams,
the 3D velocity is calculated.
AST – Acoustic Surface
Tracking
The vertically oriented
transducer in the center of
the AWAC is used to
measure the distance to the
sea surface directly by using
the simple echo sounder
principle. The center beam is
used to transmit a very short
pulse (relative to the Doppler
measurements). The travel
time from the AWAC to the
surface and back allows us
to estimate the distance to
the surface for each ping.
Data analyses
The software supplied has
been designed to provide
you with the ability to set the
AWAC up for deployment,
upgrade the firmware,
download acquired data and
do a quality assurance of
them. The data can be
converted to ASCII files that
can be imported into various
post-processing programs. In
addition, Nortek has
developed a series of real
time and post-processing
software packages that
simplifies your analyzing
work. These can be
downloaded from our
website. Contact Nortek for
valid license key
.
Содержание AWAC
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