Spatial Reference Manual
Page 43 of 158
Version 4.4
04/06/2019
A power supply should be selected that can provide at least the maximum current
calculated from the graph in Illustration 9.
Spatial contains an active protection circuit on the power supply input that protects
the unit from under-voltage, over-voltage and reverse polarity events. The protection
circuit shuts off power and automatically recovers the unit to full operation once the
fault is removed. Take care when running the unit close to its under-voltage lockout of
4.2 V because small voltage drops can engage the under-voltage shutdown and
potentially oscillate between the on and off state. It is recommended that the unit is
always run at 4.7 V or more to avoid issues associated with this.
9.5
GNSS Antenna
The GNSS antenna should be installed level with a clear unobstructed view of the sky
and close to the Spatial unit where possible. The antennas should be mounted away
from any RF emitters. The antenna cable should be routed away from powerful RF
emitters, high current wiring, high temperatures and any rotating or reciprocating
machinery. The optimum mounting configuration is above the Spatial unit.
The antenna offset should be configured in the Spatial unit by using the alignment
dialogue in the Spatial Manager software, see section 11.8.5. 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. The antenna offset is measured from the centre of the Spatial unit to the
centre of the antenna in the body frame (X forward, Z down). Please note that as Z is
positive down, mounting the antenna above the Spatial unit will result in a negative Z
offset.
An example installation with axes marked is shown below in Illustration 15 and
Illustration 16. In this installation there would be a positive X antenna offset value, a
positive Y antenna offset value and a negative Z offset value.
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 0.5
metres distance away from Spatial or remove the magnets to ensure that it doesn't
Illustration 15: Spatial antenna offset isometric
view
Illustration 16: Spatial antenna offset front view