Simrad ES70 - REFERENCE MANUAL REV A Reference Manual page 164

Simrad ES70
Parameters
• : This field allows you to define the Time Variable Gain (TVG) curve applied
TVG
to the received echoes.
–
Power (No TVG)
–
School (20 log TVG)
the bottom. It has been designed to provide the best echoes from schools.
–
Fish (40 log TVG)
bottom. It has been designed to provide the best echoes from single fish.
–
Targets (40 log TVG)
, but additional filtering is implemented. Only echoes detected and interpreted
Fish
as single fish are shown. The echoes are compensated for their physical position
in the beam (beam compensation). This means that fish in the outer region of the
beam are adjusted to correct size even though their echoes are weaker.
–
Target Mix (40 log TVG)
as , but additional beam compensation is implemented. Echoes detected
Fish
and interpreted as single fish are adjusted to their correct size according to their
physical position in the beam.
–
User (Variable TVG)
• : Use this field to select what kind of echogram you wish to see.
Echogram Type
– : The echogram is related to the sea surface. Start depth (upper echogram
Surface
boundary) and vertical range (across echogram) are manually selected by the
and
Depth Range
→ Start Range on page 114
→ Range on page 113
– : The echogram is related to the detected bottom. Stop depth (lower
Bottom
echogram boundary) and vertical range are manually selected by the
and buttons on the
Range
having a successful bottom detection.
– : This echogram is nearly identical to the
Pelagic
biomass calculations are not restricted by the bottom detection. This means that the
bottom echo will be included in calculations if it appears within the chosen range.
Example: If you are investigating a large school of pelagic fish, set the
and
Range Range
echogram may mistake it for bottom, and the biomass readings will be wrong. The
echogram will however disregard the bottom detection, and give a correct
Pelagic
estimate of the biomass.
– : Trawl sensor systems communicate headrope depth and
Trawl
headrope-to-footrope distance to the ES70 at regular intervals. The echogram
covers the vertical opening of the trawl including a small margin at each side.
The headrope and footrope margins are identical. The biomass calculations are
not restricted by the bottom detection.
9. Note that this
Targets (40 log TVG)
10. Note that this
Target Mix (40 log TVG)
162
: TVG gain is not implemented. This setting is hardly ever used.
: This gain setting provides the largest amplification close to
: This gain setting provides lower amplification close to the
: Basically, this setting uses the same TVG amplification as
: Basically, this setting uses the same TVG amplification
[10]
: This setting allows you to define your own TVG setting.
buttons on the
Main
menu. The echogram is only drawn for pings
Main
to enclose the school. If the school is large enough, a Surface
setting is only functional with split beam transducers.
setting is only functional with split beam transducers.
menu.
echogram. However, the
Surface
[9]
Start
Start Depth
Start
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