Echo Averaging - Furuno FA Manual

1. RADAR OPERATION
1.27

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 suppressing 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. Roll the trackball to choose the PICTURE box at the left side of the display.
2. Push the right button to show the PICTURE menu.
3. Roll the wheel to choose 3 ECHO AVERAGE and then push the wheel or the
left button.
4. Roll the wheel to choose OFF, 1, 2 or 3 as appropriate and then push the
wheel or the left button.
OFF: Echo averaging OFF
1:
2:
3:
5. Push the right button to close the menu.
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Helps distinguish targets from sea clutter and suppress brilliance of
unstable echoes.
Distinguishes small stationary targets such as navigation buoys.
Stably displays distant target.