Settings
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Chapter 4: Setup of the antenna
4-17
3. Click
Apply
.
4. Select the desired position mode.
5. Click
Apply
.
4.2.5 Operation in gyro-free mode
Heading input: none
If input from a gyro compass is not available, information from the GPS position is
used when searching for a satellite.
When the antenna does not have ship heading input from the vessel's gyro compass,
the azimuth direction of the satellite is not known. In this case the antenna will start a
360 degrees sky scan and scan until it finds a satellite. The satellite search time to find
the satellite and start tracking is therefore raised considerably. If the ship is on a
steady course and sails at a speed over ground above 5 kn, the system can use an
estimated heading from the current GPS position. This will reduce the search time, but
it will still be a longer search time than with heading input.
This mode can be difficult for inclined orbit satellites and elevations <5 and >70
degrees, see the following sections for details.
If a system loses the signal from the satellite, i.e. due to blockage, and the duration of
signal loss is longer than approximately 1 minute, a system without heading input
must do a new sky scan to find the satellite when the antenna is out of blockage.
Inclined orbit satellites
If the wanted satellite is an inclined orbit satellite, the system does not have any
information of the satellite latitude position but only information about inclination.
This means longer search times, depending on the maximum inclination. With the
increased search time for a system without heading input the search time can be so
long that it will be more or less useless in practice.
Position mode
Description
Mode
Select one of the following:
• GNSS (default)
• Manual
• External
GNSS
Select one of the following:
• GPS (default)
• BEIDOU
• GPS + BEIDOU
• GLONASS
• GPS + GLONASS
Latitude, Longitude,
Altitude
Only if
Position Mode
is set to
Manual:
Enter the
values
Table 4-15: Position modes
