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INSTALLING THE ACU
Connecting the System without a Gyrocompass
For a vessel where the ship’s gyrocompass is not installed or is difficult to be
connected, the Intellian Gyro-Free satellite search function will be automatically
enabled to allow the antenna to lock onto the desired satellite without requiring an
external heading input.
The table below provides an example of the Gyro-Free satellite search algorithm.
The Search 1 or Search 3 satellite search pattern will be triggered dependent on
either there being a heading source available and the heading devices data being
fed to the ACU.
Search 1: The antenna will search for the target satellite by turning its azimuth angle
in a CCW (counter clockwise) direction, until the system receives from the
modem a carrier lock signal or the NID is identified for a DVB transponder,
dependent on the configuration of the system in use.
Search 3: The antenna will search for the target satellite by turning its azimuth angle
directly to the position calculated using the ship’s heading input and lock
onto the satellite.
Setting of Heading Device
Existence of Heading Data
No Device
NMEA /
NMEA 2000
Ground Test
With Heading Data
Search 1
Search 3
Search 3
Without Heading Data
Search 1
Search 1
Search 3
