User's Manual

Smart Systems User’s Manual Version 1.1
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displays 6.4 metres (25.6 feet) of data for the Noggin 1000.
The odometer units that appear across the top of the screen can be set to either metres
or feet (see Section 6.3.1).
During data acquisition, the current odometer position value (in the current units, either
metres or feet) is written to the lower left corner of the screen (see Figure 6-1).
Note that Smart Systems can be configured to collect data either by pushing or pulling
the Noggin. See Section 6.3.2 about changing the direction of data acquisition.
The odometer should be periodically re-calibrated to ensure accuracy. The procedure for
re-calibrating the odometer is described in Section 6.5.2.
Reducing Data Quality by Moving too Fast
On the lower part of the data acquisition screen, beside the current odometer position
value is a single digit number that usually displays one (1). This value is the Repeat
Trace number.
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 Repeat Trace number displays the number of
traces that are being plotted to the screen. If this number exceeds 1 or if the user notices
the data looking smeared or “blocky”, this is probably due to moving the cart too quickly.
To eliminate this either slow down the system speed, decrease the number of Stacks or
reduce the Depth setting (see Section 6.3.1).
If the cart is being 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”.
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 6.3.1).
Backing up the Cart 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 6-1). 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.