JRC JMA-3400 Series, Instruction Manual

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Chapter 4 VRM AND EBL FUNCTION
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4.3 EXAMPLE OF EBL FUNCTION
Example: EBL function.
How to change the EBL
Press the MULTI control, select
EBL1/2 and turn the MULTI control left
or right to change the EBL direction.
Target bearing is displayed.
Press the EBL button, and turn the MULTI
control left or right to change the EBL
direction.
Or
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FOR REFERENCE
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ABOUT EBL/VRM FUNCTION
The target direction and range information can be measured by EBL and VRM function.
Bearing measurement method:
(1) The RELATIVE BEARING which is measured from own ship heading line.
(2) The TRUE BEARING which is measured from the north line.
Certainly, TRUE BEARING is calculated by RELATIVE BEARING and GYRO BEARING.
So, to calculate the TRUE BEARING is necessary a signal from GYRO or GPS compasses.
In case of no external bearing signal, display only RELATIVE BEARING mode.
Target tracking function (TT) and display AIS symbol is necessary the GYRO or GPS compass signal.
When GYRO or GPS compass signal is received, normally azimuth is measured from the north (TRUE AZIMUTH).
This radar scanner has a microwave BEAM WIDTH is about 4 degrees (NKE-2043), 2 degrees (NKE-2063A), 1.9
degrees (NKE-2103-4) or 1.2 degrees (NKE-2103-6).
So every target echo has more than 4 degrees, 2 degrees, 1.9 degrees or 1.2 degrees width for bearing direction.
For above reason, in case of read out the target azimuth, you need set EBL line to the center of the target echo.
RANGE of target echo in any azimuth can be measured by the VRM function from own ship.
Target echo size is proportion to pulse width which transmitted from own ship.
In case of MEASURE SHORT RANGE ECHO using VRM, you need set ring to the echo’s nearest point from own ship.
At that point, you can get the correct RANGE for any pulse width.
Floating:
The base point of EBL/VRM can be set other than own ship position. Refer to "5.18.1 EBL."
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