Download Simrad FS70 - REV 3 User manual

Simrad ES70
Description
Several specific parameters are
available for studies of single fish. In
order to detect single fish correctly,
these parameters must be defined to
suit the target characteristics.
Parameters
1
Min. Threshold (dB)
The target strength for a single
target must exceed this threshold
to be accepted.
2
Min. Echo Length
For a single target detection to
occur the normalized echo length
must exceed this parameter.
3
Max. Echo Length
A single target detection requires the normalized echo length to be less than the
maximum echo length setting.
4
Max. Phase Deviation
Average electrical phase jitter between samples inside an echo from a single target
must not exceed the maximum phase deviation setting where maximum phase
deviation is set in units of phase steps (128 phase steps = 180 electrical degrees).
Recommended setting is 2 to 3 for normal conditions. For weak echoes in noisy
conditions you should allow for more jitter (4 to 10).
5
Max. Gain Compensation
The correction value returned from the transducer gain model must not exceed
the maximum gain compensation setting. (This is the one-way maximum gain
compensation. The two-way maximum compensation will be 12 dB). All single
targets outside the angle corresponding to the chosen gain compensation are
skipped. Thus you can reduce the sample volume (beam angle) by choosing a lower
value for maximum gain compensation.
6
Min. Echo Spacing
The is the minimum spacing between two single echoes required for acceptance.
7
Calibration
This function is not used on the ES70.
Related topics
• EK500 Datagram on page 257
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