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The connector should be mated using its correct keying position and orientation. The screw thread should be
tightened to fully mated position. If using an Advanced Navigation supplied cable, a visible red band indicates
that the connector is not mated correctly. See
7.6 Power Supply
A high level of power supply filtering has been built into Boreas; however, it is still recommended that the power
supply be free of significant noise. Boreas contains a fully isolated power supply and has separate grounds for
power and signals to ensure that power supply noise does not corrupt communications or cause ground loops
with other equipment. See
for more details about isolation.
The power supply should be able to supply the maximum current at the chosen voltage plus a safety factor for
any extreme operating conditions (for example at high temperatures), calculated from the maximum power
indicated in the
.
Boreas 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 using a supply voltage close to the under-
voltage lockout of 9.1 V, as small voltage changes could engage the under-voltage shutdown and potentially
oscillate between the on and off state unexpectedly. It is recommended that the unit is always run at 9.5 V or
higher.
7.7 Electrical Domains
Boreas contains separate electrically isolated domains. Each domain is isolated from the others to minimise
noise injection and avoid ground loops. Where possible, this isolation should be preserved by externally
connected devices. We recommend connecting the enclosure to your vehicle ground where possible for the
best electrical noise performance.
Domain Name
Affected Components and Ports
Chassis
Enclosure, GNSS receiver, GNSS antennas
Power
Power Supply
Serial
Primary port, Auxiliary port, CAN port
GPIO
GPIO 1 port, GPIO 2 port, 1PPS port
Ethernet
Ethernet port
Table 21: Boreas Electrical Domains
7.8 GNSS Antennas
The GNSS antennas should be installed level with respect to each other, with a clear unobstructed view of the
sky, away from reflective surfaces and with the shortest cable run to the Boreas unit permitted by the
application. The antennas should be mounted away from any RF emitters such as radars, high- powered
communication links, etc. It is important to have a ground plane (flat conductive surface such as a piece of plate
aluminium) under the antenna with a minimum radius of 60mm or as recommended by the antenna supplier.
Correct antenna positioning is critical for Boreas's dual-antenna heading function.
The primary GNSS antenna position offset should be configured in the Boreas unit by using the Alignment page
in the web UI or Boreas Manager. See
9.1 Using the Web User Interface
or
.The
antenna offset is measured from the physical centre of the Boreas unit to the central base (ARP) of the primary
GNSS antenna in the body co-ordinate frame (X+ forward, Z+ down).
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11 Oct 2022
Boreas Reference Manual • Installing Boreas