NORTHROP GRUMMAN NAVITWIN IV, Operation, Installation And Service Manual

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056360/E NAVITWIN IV
1-6 Standard System Configurations
Triple NAVIGAT Gyrocompass Systems
Triple gyrocompass systems with NAVIGAT X MK 1 or NAVIGAT 2100 /
NAVIGAT 3000 gyrocompasses include a NAVITWIN IV as the system‘s
central operating unit and two cascaded Switch-Over Units to distribute
data from the compasses to external equipment.
At the NAVITWIN IV, any of the gyrocompasses may be activated to
become the heading reference for external equipment, such as heading
control systems, RADAR, compass repeaters etc.
In conjunction with a Sperry Marine fluxgate sensor, type 4863, the
NAVITWIN IV also provides an independent magnetic compass heading
source (TMC function). In case of failure of all three gyrocompasses, the
magnetic compass may be activated to provide an emergency heading
reference for repeaters and other peripheral equipment.
The NAVITWIN IV applies magnetic variation to the raw sensor value
and provides a correction table to compensates for the sensor‘s devia-
tions from the magnetic compass heading.
The “heading diff.” alarm function permits to monitor any two of the
gyrocompasses against each other or any gyrocompass against the
magnetic compass heading.
The “off heading” alarm function permits to monitor the difference
between the actual heading and the heading to steer received from a
heading control system.
Operating parameters entered at the NAVITWIN IV are transmitted to
the NAVIGAT gyrocompasses. In turn, alarms generated by the com-
passes are indicated and may be acknowledged at the NAVITWIN IV.
Figure 1-3 below illustrates how the active source selection at the
NAVITWIN IV controls the distribution of data from the compasses, via
the Switch-Over Unit, to external equipment.
Figure 1-3:
Data distribution in
a NAVIGAT *Triple gyro-
compass / TMC system
* The NAVIGAT 3000 is as well representative for the NAVIGAT 2100,
not shown in the above figure.
GYRO
1
246.8
MAGN
COMP
247.0
GYRO
2
246.7
GYRO
3
246.6
Switch-Over
Unit
to external
equipment
NAVITWIN IV
source selection
Switch-Over
Unit
mag. hdg.
Magnetic
Compass
NAVIGAT X MK 1 or
NAVIGAT 3000
NAVIGAT X MK 1 or
NAVIGAT 3000
NAVIGAT X MK 1 or
NAVIGAT 3000
G/M G/G3 G1/G2
NAVIGA
NAVIGA
GYR GYR GYR GYR GYR GYR GYR GYR GYRO GYRO GYRO GYR GYR GYR GYR GYR GYR GYR GYR GYR GYR GYR GYR GYR 246.8
mag
. h
dg.
mag
dg.
mag
. h
dg.
mag
. h
dg. dg.
. h . h
dg. dg.
G/G G/G G/G
3 3 3
G/G G/G G/G G/G G/G G/G G/G G/G G/G G/G
3 3 3 3 3 3 3 3 3 3
G1/
G2
NAVIGA