Heading Initialisation; Time Initialisation; Hot Start - Advanced Navigation Spatial Dual Reference Manual

dialogue in Spatial Dual Manager, see section 11.8.12.
Once navigation initialisation is complete, the position, velocity and acceleration
values will be valid.
10.1.3

Heading Initialisation

Heading initialisation completes once the system has determined a heading. The
conditions required to determine a heading depend upon the heading source being
used, see section 10.4. The default heading source is dual antenna heading and this
will initialise the heading within several minutes of power on assuming both antennas
are connected with a clear unobstructed view of the sky. The system can be stationary
or moving during this initialisation. If the system is hot starting it will remember it's
heading from when it was switched off and use this as the starting heading until
another source becomes available.
Until the heading has been initialised, the system will not be able to navigate without
a GNSS fix and the roll and pitch values will not be able to reach full accuracy.
10.1.4

Time Initialisation

Time initialisation completes once the system has determined time accurately. This
occurs as soon as the GNSS receiver obtains it's first fix. It is also possible to provide
an external source of time, see section 12.2 for more information on external time
sources.
Until the time has initialised the values of unix time and formatted time that Spatial
Dual outputs will not be valid and may change.
10.2

Hot Start

Spatial Dual is the first GNSS/INS on the market with hot start functionality. This allows
Spatial Dual to start inertial navigation within 500 milliseconds and obtain a GNSS fix
in as little as 3 seconds. Spatial Dual's hot start is always on and fully automatic.
A next generation backup battery system within Spatial Dual provides the hot start
ability for more than 24 hours without power. When Spatial Dual hot starts it assumes
that it is in the same state it was when it lost power and begins navigating from that
position. The hot start also provides ephemeris, almanac and time information to the
GNSS receiver which allows it to achieve a fix far more quickly than it otherwise would.
When the GNSS achieves it's first fix, if this position deviates from the hot start
position, Spatial Dual will jump to the new position without causing any side effects to
the filter.
Whilst Spatial Dual is without power it keeps track of the time accurately to within 1
second so that the time is immediately valid on a hot start.
Spatial Dual's hot start is of particular benefit to vehicle tracking and robotics
applications. The primary benefits are immunity and fast recovery from power failure
as well as fast startup time.
Spatial Dual Reference Manual
Page 44 of 137
Version 2.3
12/04/2016