Sensors & Software Inc. NG250 ユーザーズマニュアル
Noggin
12-Survey & Map Mode
73
5)
The Repeat Trace Number which indicates when the system is being moved too fast
(see Section 12.2.7: P.74) and
(see Section 12.2.7: P.74) and
6)
The Calib button for calibrating the velocity setting (see Section 12.2.11: P.79).
If a GPS receiver is attached to the DVL (see Section 12.3.5: P.103) a message will appear in the
bottom left corner of the menu indicating whether the GPS data is successfully being logged.
The possible messages are:
bottom left corner of the menu indicating whether the GPS data is successfully being logged.
The possible messages are:
1)
GPS: DGPS fix means differential GPS data are currently being logged.
2)
GPS: GPS fix means standard GPS data are currently being logged.
3)
GPS: fix not valid means GPS data are NOT currently being logged. This is usually
because GPS satellites are not available.
because GPS satellites are not available.
4)
GPS: No Input means the GPS receiver is not operating properly. Check the settings
and test the system (see Section 12.3.5: P.103).
and test the system (see Section 12.3.5: P.103).
5)
GPS: No GGA means the GPS receiver is not outputting a GGA NMEA string that
the DVL requires (see Section 12.3.5: P.103).
the DVL requires (see Section 12.3.5: P.103).
12.2.6 Gain
During data acquisition, the Gain setting can be changed by pressing the Gain button until the
desired setting appears. This can be done while the instrument is collecting data; there is no
need to stop first.
desired setting appears. This can be done while the instrument is collecting data; there is no
need to stop first.
The signals that the Noggin system collects from the ground can be very weak, especially from
deeper objects. To see these weak signals it is necessary to amplify or apply “gain” to them.
deeper objects. To see these weak signals it is necessary to amplify or apply “gain” to them.
The Gain setting controls how much the signal is amplified. It varies from 1 to 9 with 1 the lowest
and 9 the highest. In general, if the target is relatively shallow (1-2 metres) a low gain value can
be used. If the target is deeper or if the screen seems to be blank or speckled in the lower part of
the data section, increase the gain setting. Remember, however, that if the Noggin signal is not
penetrating to the maximum depth setting, even the maximum gain setting will not show any
data.
and 9 the highest. In general, if the target is relatively shallow (1-2 metres) a low gain value can
be used. If the target is deeper or if the screen seems to be blank or speckled in the lower part of
the data section, increase the gain setting. Remember, however, that if the Noggin signal is not
penetrating to the maximum depth setting, even the maximum gain setting will not show any
data.
Figure 12-2 shows the effect of the gain setting. The data on the left has a gain of 1 incrementing
to the right up to a gain of 9.
to the right up to a gain of 9.