User Manual

 the S’ X-axis equals the S X-axis, but projected on the new horizontal plane.

 the S’ Y-axis is chosen as to obtain a right handed coordinate frame.

NOTE: Once this object reset is conducted, both inertial (and magnetic) and orientation data

will be output in the new coordinate frame (S’).

The object reset can be used to set the MTw coordinate frame to that of the object to which

it is attached (see figure below). The MTw has to be fixated in such a way that the X-axis is in

the XZ-plane of the object coordinate frame (situation A). This means that the MTw can be

used to identify the X-axis of the object. To preserve the global vertical, the object must be

oriented such that the object z-axis is vertical. The object reset causes the new S’ coordinate

frame and the object coordinate frame to be aligned (situation B).

NOTE: Since the sensor X-axis is used to describe the direction of the object X-axis, the reset

will not work if the sensor X-axis is aligned along the Z-axis of the object.

MTw coordinate frame before (A) and after (B) object reset. The new Z-axis of the sensor

coordinate frame will be along the vertical. The new direction of the X-axis will be the old X–

axis that is projected onto the horizontal plane.

11.6.6 Alignment Reset

The alignment reset combines the Object reset and the Heading reset in a single time

instant. This has the advantage that all co-ordinate systems can be aligned with a single

action. Note that the new global reference x-axis (heading) is defined by the object X-axis (to

which XZ-plane of the MTw has been aligned).

NOTE: Once this alignment reset is conducted, both inertial (and magnetic) and orientation

data will be output with respect to the new S’ coordinate frame.

new MTw

coordinate

frame (S’)

Object

coordinat

e frame

(O)

MTw

coordinat

e frame

(S)

Object

coordinat

e frame

(O)