Sensors & Software Inc. NG250 ユーザーズマニュアル
Noggin
12-Survey & Map Mode
75
The odometer should be periodically re-calibrated to ensure accuracy. The procedure for re-
calibrating the odometer is described in Section 12.5.2: P.110.
calibrating the odometer is described in Section 12.5.2: P.110.
12.2.7.1 Reducing Data Quality by Moving too Fast
On the lower part of the data acquisition screen, beside the current total number of traces
collected is the total number of traces skipped.
collected is the total number of traces skipped.
If the Smart System is being used with the odometer and is moved too quickly for the Noggin
system to keep up, traces are skipped and the quality of the survey is reduced. The skipped
traces do not actually create gaps in the data but rather, the last trace that was collected properly
is repeated. The Skipped Traces number displays the total number of skipped traces. If this
number exceeds 0 this is due to moving the system too quickly. To eliminate this either slow
down the system speed, decrease the number of Stacks or reduce the Depth setting (see Section
12.3.1: P.84).
system to keep up, traces are skipped and the quality of the survey is reduced. The skipped
traces do not actually create gaps in the data but rather, the last trace that was collected properly
is repeated. The Skipped Traces number displays the total number of skipped traces. If this
number exceeds 0 this is due to moving the system too quickly. To eliminate this either slow
down the system speed, decrease the number of Stacks or reduce the Depth setting (see Section
12.3.1: P.84).
If the system is moved too fast, after the data survey line is complete, the DVL will indicate the
total number of traces that were “skipped”. The user then has the option to Autofix the data. The
Autofix process replaces any repeated traces in the data with interpolated traces. While this
process does not solve the problem of skipping traces, it will make the data traces look less
“blocky”.
total number of traces that were “skipped”. The user then has the option to Autofix the data. The
Autofix process replaces any repeated traces in the data with interpolated traces. While this
process does not solve the problem of skipping traces, it will make the data traces look less
“blocky”.
If the number of traces skipped is a significant percentage of the total number of traces collected,
i.e. 10% or more, the operator should slow down, decrease the number of Stacks or reduce the
Depth setting (see Section 12.3.1: P.84).
i.e. 10% or more, the operator should slow down, decrease the number of Stacks or reduce the
Depth setting (see Section 12.3.1: P.84).
12.2.7.2 Backing up the Smart System to Pinpoint Target Positions
The odometer also allows the user to stop the Smart System in the middle of a survey line and
back up. When this is done, an arrow and vertical line appear on the data image and move back
along the image as the system moves backwards (see Figure 12-1). This makes it possible to
correlate a target in the data image to an exact location on the ground. Once the arrow lines up
with the target, mark the ground at the centre point of the Noggin.
back up. When this is done, an arrow and vertical line appear on the data image and move back
along the image as the system moves backwards (see Figure 12-1). This makes it possible to
correlate a target in the data image to an exact location on the ground. Once the arrow lines up
with the target, mark the ground at the centre point of the Noggin.
When the system is moved forward again to continue with the survey, the Smart system does not
start collecting data again until you reach the position where you stopped at. This feature is
useful for producing a continuous data image even if the system is backed up during the survey
line.
start collecting data again until you reach the position where you stopped at. This feature is
useful for producing a continuous data image even if the system is backed up during the survey
line.
Note that it is not possible to back up and have the arrow indicator move more than one screen.
The physical position corresponding to the Back-up arrow is the centre of the Noggin. This
position can be changed from the centre of the Noggin to any other position. See Arrow Offset on
page 90 on changing the Arrow Offset value.
position can be changed from the centre of the Noggin to any other position. See Arrow Offset on
page 90 on changing the Arrow Offset value.
12.2.8 Collecting Data in Free Run Mode
It is possible to change the triggering method from the odometer and have the Noggin system run
in Free Run (or continuous mode) (see Trigger Method on page 89). This means that the system
collects data even if it is not moving. This option is useful for collecting data when using the
odometer wheel is not practical.
in Free Run (or continuous mode) (see Trigger Method on page 89). This means that the system
collects data even if it is not moving. This option is useful for collecting data when using the
odometer wheel is not practical.