YSI SonTek RiverSurveyor, System Manual

Page: 154 / 194

SonTek/YSI Inc
RiverSurveyor System Manual (May 1, 2007)
142
9.4. Echo Sounder Conditions
I cannot communicate with my echo sounder.
There is a communication problem or the system has been configured with incorrect settings.
•
Check the connection cable between the computer and the echo sounder. Check that you
have selected the corrected serial port for your connection.
•
Make sure that the communications settings that you have configured on your echo sounder
are the same as the settings you have entered into the
Echo Sounder Communication
dialog
box (
System Communication|Echo Sounder
).
The Echo Sounder indicator light is always gray.
The Echo Sounder has not been enabled in the software.
•
Enable Echo Sounder in the
Echo Sounder Communication
dialog box (
System Communica-
tion|Echo Sounder
).
9.5. Track Window Conditions
The track display shows erratic jumps when using GPS as the track reference.
The GPS data stream that is being transmitted to your computer is losing characters. This may be
due to a loose cable or poor satellite reception.
•
Check GPS interface cables.
•
Make sure that the GPS receiver has a clear unobstructed “view” of the sky.
•
The site you are measuring may be conducive to multipath errors. For more information on
multipath errors and other GPS limitations, see §
3.4.7
–
What are the limitations of GPS?
.
•
Make sure the tabular
GPS Data
display (§
7.2.2
) is showing good values.
The current vectors in the Track Window do not look correct or show the wrong direction.
The compass may not have been calibrated correctly.
There may be significant magnetic interference to the compass.
The boat speed may be too high.
The site may be an area where moving bottom is present.
Environmental conditions (e.g., eddies, backflow) may exist that cause the flow pattern you see.
•
If necessary, calibrate your system’s compass. See §
3.8.2
–
Compass Calibration Procedure
.
•
If possible, move to a survey site less likely to be affected by magnetic interference.
•
Make sure that the mount or vessel is not the source of magnetic interference.
•
Reduce vessel speed and limit the number of sharp turns.
•
Follow the instructions listed in §
3.3.5
–
Moving Bed
for more information on detecting and
compensating for moving bed.
•
Check that you have selected the best track and velocity references (§
3.10
) for this transect.
•
Consider that the current vectors displayed in the
Track Window
may actually be correct!
The vessel is stationary, but it is moving in the Track Window.
The site may be an area where a moving bottom is present.