Gnss Antenna - Advanced Navigation Spatial OEM Reference Manual

Illustration 24: Spatial
axes aligned with car
axes
6.2

GNSS Antenna

The GNSS antenna should be installed level with a clear view of the sky and as close to the Spatial
unit as possible. The antenna cable should be routed away from high energy noise sources. The
optimum mounting configuration is above the Spatial unit. If the antenna has to be installed more
than 1 metre away from the Spatial unit, this antenna offset should be configured in the Spatial unit
by using either the Spatial Manager software or the packet protocol, see section 9.9.5. It is very
important to set the antenna offset accurately as Spatial corrects for lever arm velocities. Incorrect
GNSS antenna offset will lead to performance degradation under turning and angular rotations.
It is important to note that most GNSS antennas contain magnets for mounting. If you are using an
antenna with magnets you will need to either keep it a minimum distance away from Spatial or
remove the magnets to ensure that it doesn't interfere with Spatial's magnetometers.
If you are supplying your own antenna it is important to ensure that the antenna is able to receive
all constellations and not just GPS, otherwise you will not achieve full performance. It is also
important to select an IP67 antenna with an IP67 SMA connector, otherwise the system will not be
environmentally sealed.
It is recommended to use an antenna with the following characteristics:
• Centre frequency of 1590 MHz and a bandwidth of 35 MHz
• Gain of 20 dB
• Antenna noise factor of < 2 dB
• Out of band rejection of 35 dB @
Spatial OEM Reference Manual
Illustration 25:
Spatial axes
aligned with
boat axes
±70 MHz
Page 31 of 88
Version 2.7
Illustration 26: Spatial axes
aligned with plane axes