Operation; Initialisation; Orientation Initialisation; Navigation Initialisation - Advanced Navigation Spatial Dual Reference Manual

10

Operation

10.1

Initialisation

There are four different levels of initialisation on Spatial Dual. These are orientation,
navigation, heading and time. The initialisation can be monitored by inspecting the
status view in Spatial Dual Manager, see section 11.7.2.
After all four levels of initialisation, Spatial Dual's filter takes several minutes to
achieve it's full accuracy. It is recommended to wait two minutes after initialisation for
applications requiring high accuracy.
10.1.1

Orientation Initialisation

Orientation initialisation occurs automatically upon power on and typically completes
within several seconds. Once orientation initialisation is complete, the roll, pitch and
angular velocity values will be valid.
When Spatial Dual starts up, it assumes that it can be in any orientation. To determine
it's orientation it uses the accelerometers to detect the gravity vector. Whilst this is
occurring, if there are random accelerations present, these can cause an incorrect
orientation to be detected. To prevent this, Spatial Dual monitors the accelerometers
and gyroscopes and restarts the orientation detection if there are sudden movements.
It is however still possible under some circumstances for it to miss minor movements
and start with a small orientation error. In this scenario Spatial Dual will progressively
correct the orientation error over a period of several seconds.
10.1.2

Navigation Initialisation

Navigation initialisation completes once the system has determined a starting
position. The most common method of navigation initialisation is for the system to get
a 3D GNSS fix. If the system is hot starting it will remember it's position from when it
was switched off and use this as the starting position. The other possibility for
navigation initialisation is an external position source, see section 12.2 for more
information. In a situation where a GNSS fix is not available to initialise navigation, it
can be initialised manually by entering a position into the manual initialisation
Spatial Dual Reference Manual
Illustration 22: The
four initialisation
levels
Page 43 of 137
Version 2.3
12/04/2016