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……Gate Size ………………………………………………………………
The Gate Size is defined as an “Area within which targets are watched by the ARPA” processing circuit.
If the gate size is too large, targets are not lost but may be swapped with other close targets.
If the gate size is too small, targets are not easily swapped, but may be lost.
The ARPA processing circuit is designed to detect target sizes and set an accurate gate size depending
on the ranges and sizes of those targets (NARROW is the standard size). However, change the setting
parameters to select the best size in the following conditions:
Set in normal operation.
• When acquiring and tracking targets that spread widely in the angular direction
(The angular direction of the gate aperture is important) …………………………………
• When many targets are densely congested and swapped within 3 NM in a port
(The gate size should be reduced) ………………………………………………………
3. SMALL
1. WIDE
2. NARROW
Do not change the preset gate size carelessly. If the gate value is improper, the ARPA
acquisition and tracking functions may deteriorate.
Otherwise, this may cause accidents to occur.