4 Improving ADCP data quality with a Percent Good threshold value

Percent good is a measure of quality for velocities measured in the ADCP beams. You can enable/disable the use of percent good data and set a threshold value for acceptable/unacceptable percent good data.

Context

The term percent good is commonly used to describe the total remaining value of an asset after a certain time compared to the value of the original asset. In our context, the term is used both as a measure and a filter setting.

The Percent Good filter applies to the Vessel Velocity and Geo Velocity views. It tells what fraction of pings passed both the error velocity and correlation threshold editing. The Beam Velocity views do not use this quality measurement.

The percent good fraction is calculated using the number of pings selected with the Ping Average function. When calculating ping average, only the velocities which have passed the error velocity and correlation editing are included. The percent good threshold sets the lower limit for what fraction of pings must have passed the other threshold edits. Averaged velocities, ADCP data, with percent good below this limit are not shown in the velocity views.

Note

This is a visual enhancement. The choice you make has no effect on the overall performance of the EK80 system.

Procedure

Open the Active menu.

Select ADCP Editing.

Select the appropriate percent good threshold value.

Enabling the threshold value will increase the quality of the data and provide more correct velocity information.

Select Apply to save your choice.

Select OK to close the dialog box.