Echo Averaging - Furuno FAR-2218-BB Operator's Manual

1. OPERATIONAL OVERVIEW
1.24

Echo Averaging

The echo averaging feature effectively reduces sea clutter. Echoes received from sta-
ble targets such as ships appear on the screen at almost the same position every ro-
tation 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 succes-
sive picture frames. If an echo is solid and stable over successive frames, it is present-
ed in its normal intensity. Sea clutter is averaged over successive scans and its
brilliance reduced, making it easier to discriminate real targets from sea clutter.
Echo averaging uses a 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 reducing random echoes such as sea clutter. However, true echo
averaging is not effective for picking up small targets running at high speeds over the
ground.
Note 1: With echo average active it is harder to detect high-speed targets than sta-
tionary ones.
Note 2: Do not use the echo averaging function under heavy pitching and rolling; loss
of targets can result.
Note 3: Echo averaging requires heading, position and speed data.
Before using the echo averaging function, reduce sea clutter with the A/C SEA control.
Leave a little sea clutter on the screen so as not to erase weak targets. The available
settings options are shown in the table below.
Setting
(level)
[OFF]
[1], [2]
[3]
You can access this feature from the InstantAccess bar
How to adjust the echo average function from the InstantAccess bar
Select the [EAV] button (
the desired level of echo averaging.
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Echo averaging is not enabled
Detects targets hidden in sea clutter. [2] is more effective than [1] in detecting
targets hidden in strong sea clutter. However, [1] is more effective than [2] in
displaying high-speed targets. Select the setting best suited to current con-
ditions. For effective monitoring of high-speed craft, you should use [2] to-
gether with the Wiper function.
Stably displays unstable targets; distinguishes high-speed craft.
EAV
) on the InstantAccess bar
OFF
Description
™
, or from the menu.
™
, then left-click to select
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