JRC JMA-5212-4/6 User Manual page 253

Relative Vector Mode
In displaying the relative vector of a target, press the [VECT R/T] key to select the Relative Vector mode.
The relative vector does not represent the true motion of the target, but its relative relation with own ship.
This means that a target with its relative vector directed to own ship (passing through the CPA LIMIT ring) will
be a dangerous target. In the Relative Vector mode, it can be seen at a glance where the CPA LIMIT of the
dangerous target is.
CPA ring
Therefore, the TRUE/REL mode shall optionally be used for the purpose of observation: the TRUE vector
mode for grasping the true aspect of a target, and the REL vector mode for grasping a target's closest point of
approach (CPA)
[II] Vector Length: VECTOR TIME
The vector length of a target is proportional to its speed, and the vector time can be switched in a range of 1 to
60 minutes by used for ten-key.
The diagram below illustrates a vector length of a target for six minutes, and the tip of the vector represents the
target's position expected to reach six minutes later.
Refer to Section 5.1.7 "Setting Vectors (Vector Time)" for how to change the vector time.
HL
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5.1 PREPARATION
The true vector is
not displayed
Relative vector
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yyy
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