JRC JMA-3300 Series, Instruction Manual, Page: 85 / 298

Chapter 2 OPERATIONS
2.7 SOFT KEY OPERATION
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Setting AIS Symbol Display
For details of displaying/hiding of the AIS symbols, see Section "2.7.16 SETTING
SYMBOL ".
2.7.7
TT OPERATIONS
The target tracking function calculates the course and speed of a target by automatically
tracking the target's move.
Note:
z
There are the following limitations on use of the target acquisition and target
tracking functions.
[I] Resolution between adjacent targets and swapping during automatic target
tracking
Depending on the particular distance and echo size, resolution between
adjacent targets during automatic target tracking usually ranges somewhere
between 0.03 to 0.05 NM. If multiple targets approach each other, resolution will
become about 0.05 NM and this may cause the system to regard them as one
target and thus to swap them or lose part of them. Such swapping or less of
targets may also occur if the picture of the target being tracked is affected by
rain/snow clutter returns or sea clutter returns or moves very close to land.
[II] Intensity of echoes and the target tracking function
The intensity of echoes and the tracking function have a correlationship, and
thus the target will be lost if no echoes are detected during seven scans in
succession.
If a lost target exists, therefore, radar gain must be increased to support
detection of the target. If, however, radar gain is increased too significantly, sea
clutter returns or other noise may be erroneously detected and tracked as a
target, and resultingly, a false alarm may be issued.
To execute accurate tracking, it becomes necessary to appropriately adjust the
[GAIN], [SEA] and [RAIN] controls of the radar so that the target to be acquired
and tracked id clearly displayed on the radar display.
Inappropriate settings of these adjustments reduce the reliability / accuracy of
automatic tracking.