Gnss Antenna Cables; Odometer; Factory Vss Signal - Advanced Navigation Spatial Dual Reference Manual

Omnistar and SBAS. It is environmentally sealed to the IP68 standard.
If you are sourcing your own antenna, please note the following antenna guidelines:
The antenna should be capable of receiving both L1 and L2. Heading
•
performance will be significantly degraded with an L1 only antenna.
The antenna needs to have an accurate phase centre to be RTK capable. This is
•
required for the dual antenna heading to function correctly. Low performance
(low cost) antennas are typically not able to achieve good heading performance.
The antenna should have an LNA gain of at least 35dB.
•
The antenna should support both GPS and GLONASS.
•
The antenna should be environmentally sealed, including connectors.
•
If you are sourcing your own antenna cables it is important to ensure that the antenna
has enough gain to support the loss over the cable. Spatial Dual requires a minimum
of 33dB of gain at the connector. With the standard 4 metre LMR240 antenna cables
supplied by Advanced Navigation, the minimum antenna gain is 34.5dB.
9.6

GNSS Antenna Cables

The antenna cables should be routed away from powerful RF emitters, high current
wiring, high temperatures and any rotating or reciprocating machinery. It is very
important not to bend the antenna cable beyond it's maximum bend radius. It is
recommended to use wide cable ties and be careful not to do them up too tight.
Advanced Navigation recommends using either RG58 low loss or LMR240 coaxial cable
combined with high quality connectors. LMR300 and LMR400 can also be used to
minimise loss for very long antenna cables.
Cable Type
RG-58/U Low Loss
LMR240
LMR300
LMR400
Table 17: GNSS antenna co-axial cable properties
9.7

Odometer

On ground vehicles, the use of an odometer input can greatly improve Spatial Dual's
navigation and orientation solution during GNSS outages. With a high resolution wheel
encoder Spatial Dual can be used to navigate indoors with GNSS disabled altogether.
There are several different options for odometer installation which are listed below.
9.7.1

Factory VSS Signal

Most road cars since 1980 contain a VSS (vehicle speed sensor) signal that can be
wired directly into one of Spatial Dual's GPIO pins. The vehicle should be taken to an
Minimum Bend Radius
20 mm
20 mm
22.2 mm
25.4 mm
Spatial Dual Reference Manual
Page 39 of 137
Version 2.3
12/04/2016
~0.92 dB/m
~0.33 dB/m
~0.26 dB/m
~0.17 dB/m
Signal Loss