YSI SonTek RiverSurveyor, Системное руководство

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SonTek/YSI Inc
RiverSurveyor System Manual (May 1, 2007)
141
•
Move the survey site to an area away from vertical walls, away from areas with sharp
changes in slope, and away from areas with a large amount of vegetation on the bottom.
These areas can cause large differentials in the individual beam depths.
Some of the GPS parameters seem incorrect or differ greatly from bottom-track data.
You may be experiencing a “moving bed”, or your compass may need to be calibrated.
•
Follow the instructions listed in §
3.3.5
–
Moving Bed
for more information on detecting and
compensating for moving bed.
•
If necessary, calibrate your system’s compass. See §
3.8.2
–
Compass Calibration Procedure
.
•
Ensure the correct magnetic declination value is being used. See §
6.6.4
.
9.3. GPS Conditions
I cannot communicate with my GPS.
There is a communication problem or the system has been configured with incorrect settings.
•
Check the connection cable between the computer and the GPS. For RiverCat systems,
check the cable between the GPS receiver and the electronics housing. Check that you have
selected the correct serial port for your connection.
•
Make sure that the communications settings that you have configured on your GPS receiver
are the same as the settings you have entered into the
GPS Communication
dialog box (
Sys-
tem Communication| Show GPS Data
).
The GPS indicator light is always gray.
GPS has not been enabled in the software.
•
Enable GPS in the
GPS Communication
dialog box (
System Communication| Show GPS
Data
).
The system keeps losing GPS or the GPS indicator light keeps turning red.
The GPS receiver may not be receiving valid data.
The GPS may not be able to receive information from a sufficient number of satellites.
•
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?
.
Some of the GPS parameters seem incorrect or differ greatly from bottom-track data.
You may be experiencing a “moving bed”, or your compass may need to be calibrated.
•
Follow the instructions listed in §
3.3.5
–
Moving Bed
for more information on detecting and
compensating for moving bed.
•
Use a DGPS receiver with sub-meter accuracy.
•
If necessary, calibrate your system’s compass. See §
3.8.2
–
Compass Calibration Procedure
.
•
Ensure the correct magnetic declination value is being used. See §
6.6.4
.