RT User Manual
Revision: 190902
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ISO 8855 ENU earth-fixed system
Table 13. ISO 8855 ENU earth-fixed system
Axis
Description
East
The east axis (E) is perpendicular to gravity, perpendicular to the north axis and is in
the east direction.
North
The north axis (N) is perpendicular to the gravity vector and in the direction of the
north pole along the earth’s surface.
Up
The up axis (U) is co-axial with the gravity vector, and positive in the up direction.
Figure 6. ISO 8855 ENU earth-fixed system
The ISO earth-fixed system is attached to the vehicle but does not rotate with it. The north and east axes
are perpendicular to the gravity vector and north always points north.
OxTS horizontal frame
The OxTS horizontal frame (sometimes called the level frame) is attached to the vehicle
but does not rotate with the roll and pitch of the vehicle. It rotates by the heading of the
vehicle. The definition of the OxTS Horizontal frame is listed in Table 14 and shown in
Figure 7.
