SonTek, a Xylem brand
RiverSurveyor S5/M9 System Manual (February 2013)
101
d)
Differential quality GPGGA data (sub meter accuracy). It usually takes ap-
proximately 5 minutes to connect to this level of quality of data. No action required
by user unless RTK quality is required. Be sure that the systems (Base Station and
RiverSurveyor) have clear sky view antenna and that SS connections are correct.
e)
Indicates that communications have been established between the
system and satellites, however there is no sub-meter differential correction. Gener-
ally not recommended for discharge calculations. Users should make sure that
they have a clear sky view. Time needed to establish a connection between Sys-
tem and Satellites: 5 minutes for Differential quality data or up to 10 minutes for
RTK quality data.
f)
and/or
Connection not valid. Action required: Revise all cable con-
nections and be sure to have a clear sky view for antenna. Be sure that the battery
pack is sufficiently charged.The GGA and VTG icons will also display red if you run
RSLv. 3.60 with
g)
and/or
GPS not available or not installed. If you are using an exter-
nal, serially connected GPS, make sure that you have the correct baud rate
(38400) and the $GPGGA and the $GPVTG serial data strings are being output
from your GPS unit.
h)
GPVTG data (highest quality VTG data—measured velocity data). It
typically takes approximately 5 minutes to connect. No action is required as this is
the highest level of VTG data available. To maintain this level of data quality, make
certain that RiverSurveyor have clear sky view At least 6-7 satellites are required
for reliable VTG data. Satellite changes can affect track data and should be moni-
tored during data collection. Similar to differentially-corrected (not RTK) GGA data,
VTG data are best suited to streams greater than 20 meters across. The best VTG
data are obtained when the vessel motion is constant. Additional transects may be
advisable if VTG accuracy is in question during a discharge measurement.
i)
Mean Bottom Track depth is used for depth calculation.
j)
Vertical Beam depth is used for depth calculation.
