Document MT0605P.E
© Xsens Technologies B.V.
MTi User Manual
31
accelerations). Based on the rate gyros the attitude and heading estimates will
degrade slowly (typically a degree every minute).
Valid holonomic constraints (MTi-G-700 only)
: In several filter profiles of the MTi-G-700 it is
assumed that the x-axis of the MTi-G is mounted in the driving direction of the vehicle. If this is
not the case within about 1 degree, the estimated heading and position specification may not
be obtained.
Barometric conditions (MTi 100-series only):
In some of the filter profiles, the altitude of the
MTi-G-700 is partly estimated by the on-board barometer. It is assumed that the pressure near
the MTi-G reflects the atmospheric pressure outside of the vehicle. So, if you selected a filter
profile that uses barometer data, the MTi-G cannot be used in e.g. a pressurized cabin.
Furthermore, the height accuracy may reduce with very rapid changes in atmospheric
pressure that could occur in e.g. severe thunderstorms.
4.4 Position and velocity performance specification (MTi-G-700)
The MTi-G-700 has the ability to output position. The performance highly depends on the GPS
availability, placement of the GPS antenna etc.
The table below states the position and velocity accuracy according to Xsens’ reference trajectories,
as explained in [MTI_TD].
Parameter Data source
Condition Specification
Position
AHRS augmented (400 Hz GPS/INS), SBAS
Horizontal
1.0 m STD
Vertical
2.0 m STD
GPS receiver (4 Hz GPS navigation solution), SBAS
Horizontal
2.0 m CEP
Vertical
5.0 m CEP
Velocity
AHRS augmented (400 Hz GPS/INS)
@ 30 m/s
0.1 m/s 1
σ
RMS
GPS receiver (4 Hz GPS navigation solution)
@ 30 m/s
0.1 m/s 1
σ
RMS
4.5 Orientation output modes
The orientation as calculated by the MTi is the orientation of the sensor-fixed co-ordinate system (
S
)
with respect to a Cartesian earth-fixed co-ordinate system (
L
). The output orientation can be
presented in different parameterizations:
Unit Quaternions