Kongsberg Simrad SN90 Reference Manual page 623

Tip
If you have problems with bottom detection, you may consider disabling it. This can be
useful if you only wish to study targets in the water column.
Details
Minimum Tilt for Bottom Detection
Minimum Tilt for Bottom Detection
SN90 system stop the bottom detection.
The system's ability to detect the bottom depends on the tilt angle. A beam that
points straight down detects the bottom better than a beam that hits the bottom
with an angle.
• A large tilt value makes the SN90 system detect the bottom with high accuracy.
The depth is then also accurate.
• A small tilt value reduces the bottom detection accuracy, and thus also the
accuracy of the depth.
Maximum Depth
The search for the bottom echo extends down to this depth whenever bottom
track is lost.
Use a slightly larger depth value than the deepest spot you expect to visit. This will
prevent annoyingly long ping intervals every time the bottom track is lost. A depth
value of either 0 (zero) or less than the minimum depth disables the bottom detector.
Note
If you set maximum depth to a value identical or smaller than the minimum value,
the bottom detection algorithm will be disabled. The SN90 system will not detect
the bottom at all, and the displayed depth will be 0.00 m.
Minimum Depth
The bottom detector starts the search for the bottom echo at this depth. The
detector will fail in shallow water if you select a too large depth value, and the tail
of the transmitting pulse may cause problems if a too small value is set.
Note
If you set maximum depth to a value identical or smaller than the minimum value,
the bottom detection algorithm will be disabled. The SN90 system will not detect
the bottom at all, and the displayed depth will be 0.00 m.
381294/E
Functions and dialog boxes
permits you to set a tilt value that makes the
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