1. OPERATIONAL OVERVIEW
1-25
1.23
Echo Averaging
The echo average feature effectively suppresses sea clutter. Echoes received from stable targets
such as ships appear on the screen at almost the same position every rotation of the antenna. On
the other hand, unstable echoes such as sea clutter appear at random positions.
To distinguish real target echoes from sea clutter, echoes are averaged over successive picture
frames. If an echo is solid and stable, it is presented in its normal intensity. Sea clutter is averaged
over successive scans resulting in reduced brilliance, making it easier to discriminate real targets
from sea clutter.
Echo averaging uses scan-to-scan signal correlation technique based on the true motion over the
ground of each target. Thus, small stationary targets such as buoys will be shown while sup-
pressing random echoes such as sea clutter. True echo average is not however effective for
picking up small targets running at high speeds over the ground.
Note 1:
Do not use the echo average function under heavy pitching and rolling; loss of target
detection can result.
Note 2:
Echo average can be used without a heading sensor. For further details, contact your
dealer.
To properly use the echo average function, it is recommended to first suppress sea clutter with
the A/C SEA control. Then, do as follows:
1. Press the
MENU
key to open the menu.
2. Choose the Echo menu and press the
ENTER
key.
3. Choose Echo Stretch and then press the
ENTER
key.
4. Choose the appropriate echo stretch option and then press the
ENTER
key.
5. Press the
MENU
key to close the menu.
Off
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