Tt Operations - JRC JMA-3400 Series Instruction Manual

Chapter 5 VARIOUS FUNCTIONS

5.7 TT OPERATIONS

To use the target tracking function, direction signal and GPS signal information are required. The target
tracking function calculates the course and speed of a target by automatically tracking the target's move. If
there is a possibility of a collision, an alarm can be sounded.
Furthermore, the target tracking function of this unit does not conform to IEC 62388 / 62288 in operation and
symbol display. Thus, It is a simplified target tracking function.
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 or sea clutter 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 correlation ship, and thus the target will be
lost if no echoes are detected during 10 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 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.
Use the radar only as a navigation aid. The final navigation decision must always be made
by the operator him/herself. Making the final navigation decision based only on the radar
display may cause accidents such as collisions or running aground.
Use the target tracking function (TT) only as a navigation aid. The final navigation decision
must always be made by the operator him/herself. Making the final navigation decision
based only on the target tracking function (TT) information may cause accidents.
The target tracking function (TT) information such as vector, target numerical data, and
alarms may contain some errors. Also, targets that are not detected by the radar cannot
be acquired or tracked.
Making the final navigation decision based only on the radar display may cause accidents
such as collisions or running aground.
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Note:
CAUTION