Kongsberg Simrad CS90, Справочное руководство

Страница: 620 / 686

618
442700/A
Maximum FM Phase Deviation
This setting only applies to FM operation.
Several single targets occurring at the same range will give you echoes in different
parts of the beam’s cross section. To remove the bad targets, the angle (phase) between
the samples in the echo are measured. If the angle is too large, the echoes are deleted.
If the angle at a given range is too large, this indicates multiple targets.
Maximum Gain Compensation
This setting applies to both CW and FM operation.
Not all single targets are located in the centre of the beam. Targets located off centre
will offer weaker echoes due to the beam properties. The CS90 system automatically
compensates for this using a mathematical model, and you can manually control the
effect of this algorithm by defining a maximum gain value.
Using the 3 dB setting all echoes from within the nominal beam width of the transducer
will be accepted. By reducing the value, you will only accept echoes that appear closer
to the centre of the beam. Reducing the value of this parameter will effectively narrow
the beam opening angles for single target detections, but will normally improve the
accuracy of the target strength values for the detected single targets.
Minimum Echo Spacing
This setting only applies to CW operation.
This parameter defines the minimum distance between two single echoes when you
are using CW pulses. If they are too close, the echoes are skipped.
The distance is defined as a relation to the length of the transmitted signal. Selecting 1
means that the minimum spacing corresponds to the physical distance covered by the
transmit pulse. Increasing the value will require the targets to be further separated, but
can improve the accuracy of the target strength values.
Tip
Overlapping targets will not be identified with this function. Use the
Minimum Echo
Length
,
Maximum Echo Length
and
Maximum CW Phase Deviation
to handle these.
Distance Before Target
/
Distance After Target
These settings only apply to FM operation.
The
Distance Before Target
and
Distance After Target
settings define the required
spacing before and after one target to the end and beginning of the next target. This is
the same functionality as the
Minimum Echo Spacing
function for CW operations, but
the algorithms are very different.
Simrad CS90 Reference Manual