RT User Manual
Revision: 190902
21
Hardware installation
It is essential to install the RT rigidly in the vehicle. The RT should not be able to move
or rotate compared to either GNSS antenna, otherwise the performance will be reduced.
In most circumstances the RT should be mounted directly to the chassis of the vehicle. If
the vehicle experiences high shocks, then vibration mounts may be required.
The RT is compatible with the RT-Strut product from OxTS to provide a quick and secure
vehicle mounting solution.
Do not install the RT where it is in direct sunlight as, in hot countries, this may cause the
case to exceed the maximum temperature specification.
RT orientation and alignment
The orientation of the RT in the vehicle is normally specified using three consecutive
rotations that rotate the RT to the vehicle’s co-ordinate frame. The order of the rotations
is heading (
z
-axis rotation), then pitch (
y
-axis rotation), then roll (
x
-axis rotation). It is
important to get the order of the rotations correct.
In the default configuration the RT expects its
y
-axis to be pointing right and its
z
-axis
pointing down relative to the host vehicle. There are times however when installing an
RT in the default configuration is not possible, for example when using the RT-Strut. The
RT can be mounted at any angle in the vehicle as long as the configuration is described
to the RT using NAVconfig. This allows the outputs to be rotated based on the settings
entered to transform the measurements to the vehicle frame.
For ease of use, it is best to try and mount the RT so its axes are aligned with the vehicle
axes. This saves the offsets having to be measured by the user. If the system must be
mounted misaligned with the vehicle and the user cannot accurately measure the angle
offsets, the RT has some functions to measure these offsets itself. The heading offset can
be measured if the vehicle has a non-steered axle. The Improve Configuration wizard in
NAVconfig should be used for this. Roll and pitch offsets can be measured using the
Surface tilt utility in NAVdisplay.
Antenna placement and orientation
For optimal performance it is essential for the GNSS antenna(s) to be mounted where
they have a clear, uninterrupted view of the sky and on a suitable ground plane, such as
the roof of a vehicle. For good multipath rejection the antennas must be mounted on a
metal surface using the magnetic mounts provided; no additional gap may be used.
The antennas cannot be mounted on non-conducting materials or near the edges of
conducting materials. If the antennas are to be mounted with no conductor below them
