User's Manual

Chapter 2 Radar Basic Operation MDC-5200/5500 Series
0093155002-03 2-10
2.7 Reject sea clutter (anti-SEA)
MAN (manual) SEA and AUTO (automatic) SEA are provided for
anti-SEA function. On the rough sea, SEA clutter noise appears
around antenna position (center spot), and short distant targets
are masked and not recognizable. In that case, anti-SEA function
suppresses sea clutter noise and reveals masked target echoes.
Recommended adjustment of anti-SEA is to adjust to make
echoes from sea clutter vaguely displayed by low (weak) level.
If anti-SEA level is too high to show sea clutter noise, short
distance gain is over suppressed and it may result in loss of
targets like buoys and small ships.
On the other hand, if anti-SEA level is too low, clutter noise around
antenna position (center spot) is displayed by high intensity level
and it makes difficult to discriminate small ships and buoys from
sea clutter.
Anti-SEA is effective to suppress false echoes and ground clutter
in short distance. However adjustment of GAIN should be used
beyond effective coverage of anti-SEA.
If target echoes are masked by excessive false echoes within anti-SEA effective area, then adjust MAN
SEA to confirm it. Excessive anti-SEA may lose echoes from small ships and buoys. So, return to
appropriate anti-SEA level for normal use.
Note:
• Small targets become harder to detect when [SEA] is used together with [RAIN]. Therefore, please
adjust them carefully.
• The echo process (refer to 2.23 Echo process) is useful to reject sea clutter. Be careful, when the
echo process is active, high speed targets are harder to detect than stationary ones.
Selection of MAN SEA and AUTO SEA
By SEA knob
When the SEA knob is pressed, AUTO SEA and MAN SEA change alternately.
By trackball/joystick
1 Move cursor on the MAN or AUTO display (whichever is shown) at right side of [SEA] on the top of
the display.
2 Press ENT key to display AUTO or MAN as appropriate.
SEA clutter at center
After Adjusted MAN SEA