Simrad ARGUS FMCW 3G, User Manual

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Radar presentation and video processing | Argus Radar Operator Manual
A and / or B combination
A and/or B combination (interswitch set up menu in sector combination)
This combination mode is used to get both benefits of the and/or combinations. Up to the
range where the sea clutter can be present, which depends of antenna type and height, the
combination is following the “and” mode to suppress the sea clutter correlating of the two in-
put sensors that scan the same area at slightly different time (antennas are not synchronized).
Beyond sea clutter range, the mode is switched to “or”, where it can improve the detection of
far/dim echoes.
Warning:
Since the inputs to two antennas, that are not synchronized, are being com-
bined, the delay between the updates of the two images can be as much as one scan of
the antenna (the fastest one). If the ship manoeuvers at a speed above ~40°/min, the same
echo could appear twice in the same scan.
Radar echoes of the size listed in the following table can also be represented twice on the
screen. The table takes into consideration the worst case scenario of antennas that are com-
pletely out of synch by 360° and therefore, the dimension limits are usually greater than the
ones provided here, and according to the scale being used, this problem might not be visible.
Depending on the antenna rotation rate and target speed, the table shows the minimum ship
length necessary for not showing two separate echoes (in “or” mode) or an echo suppression
(in “and” mode).
V (KN) 20 rpm 40 rpm
10 16 m 8 m
20 30 m 15 m
40 60 m 30 m
70 120 m 60 m