YSI SonTek RiverSurveyor, Системное руководство

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SonTek/YSI Inc
RiverSurveyor System Manual (May 1, 2007)
163
•
# of Valid Cells
– Is the number of valid cells always greater than 2? You will need to step
through the profiles or look closely at the white line that runs along the bottom of the
Contour Window (§
7.2.6
).
4. GPS Data
•
Magnetic Declination
– Has a value been entered for the magnetic declination and if so, is it
correct? Incorrect magnetic declination can lead to significant errors in the calculated veloc-
ity and discharge when GPS is used.
•
GC-BC
– Is the angle between the GPS and bottom-track tracks close to 0 or 360?
•
D(BT)/D(GPS)
– Is the ratio of bottom-track track distance to the GPS track distance close to
1.00 for each profile?
•
GPS Quality Parameters
(satellites, altitude, HDOP, etc.) – Are the GPS quality parameters
valid and were there any problems using the GPS? Is it valid to use the GPS for track and/or
velocity references? GPS should not be used in conditions when the GPS signal is unreli-
able or intermittent. This is indicated by significant changes in the number of satellites, an
insufficient number of satellites being detected (less than 4) or sudden, dramatic changes in
altitude. Also, discharge data should always be collected with a differentially corrected GPS
signal. Using GPS without differential corrections will cause large variations and inaccura-
cies in the discharge measurement values.
5. Sensor Data
•
Temp
– Is the water temperature realistic? The temperature should remain stable throughout
the entire measurement.
•
Avg. Heading
– Is the average heading for the transect realistic? How does it compare with
the boat track? Does it stay relatively constant throughout the measurement?
•
Avg. Pitch + Avg. Roll
– Is the average pitch and roll for the transect realistic? Are they rela-
tively constant? Significant changes in pitch and roll or if the average pitch or roll is greater
than 5 degrees could introduce errors or variability into the measurement.
•
Salinity
– Is the salinity correct and valid/consistent for all measurements? Remember: 0 ppt
for Freshwater; 34.5 ppt for salt/sea water. Salinity can be adjusted in post-processing. Us-
ing 34.5 ppt in freshwater (0 ppt) results in about a 9% error in discharge.
•
ADP Xducer
– Is the ADP transducer depth correct? If the automatic transducer depth meas-
urement system has been used, review the pressure and depth calibration log files.
•
Echos Xducer
– Is the echo-sounder transducer depth correct (if applicable)? Was a bar
check made to calibrate the echo sounder?
•
Voltage
– Is the system voltage valid (12-24 volts)? Voltage is critical for RiverCat systems.
E-5. Step 5 – Review System Hardware Parameters
Press
Ctrl+H
to check the system hardware parameters. Briefly review all the parameters but pay
particular attention to the following:
•
Serial #
– Is the serial number displayed in the ADP Hardware Configuration dialog identi-
cal to the system that was used in the field? Does the serial number match the field sheet
and the value entered in the Discharge Summary report?
•
Sensor Orientation
– Is the sensor orientation down?
•
CPU Software Version #
– Is the version current? Contact SonTek/YSI, Inc. for the latest
version only if necessary.