Suspending target strength data for individual hits
This procedure explains how to delete target strength data “hits” that are in obvious error. In the TS Data list, you can suspend individual echoes from the calibration processing.
Prerequisites
Collecting calibration data must be an ongoing process or recorded previously.
Context
The calibration process uses a sphere with a specific diameter and of a specific material which yields a known target strength. During the calibration process the known target strength is used as a reference to adjust the actual target strength values obtained. When data is collected, you may also acquire “hits” from other targets in the sea. Such targets could be fish or objects in the water column, or simply the result of noise.It is advantageous to delete such erroneous hits, as these would have a negative effect on the calibration accuracy.
Clicking on a target in the Suspend mode will mark this target in pink colour, and exclude it from all calculations. The suspended target will remain in the data set, and it can be “unsuspended” by clicking on it one more time.
Procedure
1 Open the TS Data page in the Numerical field to access the individual echoes.
2 Observe the Range column in the Numerical field to access individual echoes.
a Select Range at the top of the column to sort the list according to range.
b Identify hits with ranges that exceeds the expected values.
3 Observe the TS-Comp column in the Numerical field to access individual target strength compensated values.
a Select TS-Comp at the top of the column to sort the list according to range.
b Identify hits with target strength values that differ noticeably from the other values
4 Observe the Time column in the Numerical field to access individual values.
a Select Time at the top of the column to sort the list according to range.
b Identify hits that have been recorded outside the time range that was used to collect the calibration data.
5 Suspend the chosen hits.
a Select Suspend at the bottom of the information field.
b Select the echoes to suspend by clicking the row.
c Suspended echoes are marked pink in the information field.
Tip
If you wish to suspend multiple hits adjacent to each other, click once on the first hit. Hold the keyboard Shift button depressed, and move up or down using the Arrow keys.
d Click one more time on the same hit if you whish to include it again.