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7 Carrier Phase Data Collection
In Figure 7.2, the counter begins at time zero and stops at 35 minutes
when lock is lost (B). This creates the first block of carrier phase data.
If you specified a minimum time of 30 minutes, for example, this first
block contains sufficient useful data. It should produce positions that
meet the precision you require.
Between B and C, the required minimum number of satellites is not
met. The counter does not start, and the carrier phase data collected
during this period is not used.
When four satellites are again available (C), the Asset Surveyor
software creates a new block and the counter begins to measure again
from time zero. In this example, this happens 38 minutes after the start
of the session. Lock is lost at 55 minutes (D)—after only 17 minutes
worth of data has been collected. Since you specified a minimum time
of 30 minutes for this session, this block contains insufficient
continuous data.
This is likely to result in data that may not produce positions that meet
the precision you require.
7.2.6 Recording Features
While the Asset Surveyor software logs carrier phase measurements in
the background, you start to record features—these can be points,
lines, or areas.
Decide carefully when to start and stop recording feature data.
Before you start the first feature in your file, wait until four or more
satellites are available. Once you are receiving carrier phase data from
at least four satellites, the Asset Surveyor counter starts.
Ending a feature before minimum time is reached
Once the counter is running, you can choose to end the feature and
stay where you are until the minimum time is up. When the success
beep sounds, you can move to the next feature. Using this method, you
can be sure that you have sufficient data to generate precise positions.
168 TSC1 Asset Surveyor Operation Manual