When collecting average current data with a Signature instrument, two data files will be generated and stored to the recorder:
- [filename].ad2cp: This file contains raw, single-ping data with no quality control applied
- [filename]_avgd.ad2cp: This file contains averaged current data. The data is averaged over the configured average interval, and internal quality control is applied before averaging.
The internal quality control done to the [filename]_avgd.ad2cp file discards all pings with a correlation below 50 % before averaging. This filtering is irreversible and ensures consistent data quality. For more information about the correlation parameter, please refer to the Correlation - theoretical background.
Percent good
In the averaged current data (found in the [filename]_avgd.ad2cp file) there is also a Percentage Good value which indicates the percentage of valid pings retained in each cell during an average interval after the internal quality control.
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Example You have configured your instrument to do 10 pings within each average interval. One ping in the first cell is discarded because its correlation is below 50 %. The resulting Percent Good value will be 90 % for this cell. |
If the Percent Good value is lower than 50 % (meaning more than half the pings were discarded due to low correlation), the entire cell is flagged. Flagged data will be represented by extreme placeholder values:
- Velocity: -32.767 m/s
- Speed: 46.34 m/s
- Direction: 225°
Updated