Applicable to the coordinate systems used in ADMA (except for the positions):
• They are right-handed Cartesian coordinate systems
• Direction of rotation by the positive axis direction follows the “right hand rule”
The ADMA measuring axis coordinate system
The identification label of the ADMA shows the alignment of the measuring axes of the ADMA relative to the housing. The X axis points away from the observer.
If the measuring axes of the gyro system are aligned parallel to the axes of the body coordinate system of the vehicle, then both coordinate systems correspond.
The aim of every setup should be that both coordinate systems overlap (measuring axes ADMA and the body coordinate system) which can be accomplished using the corresponding assembly and by compensation through the fitting position offset.
The body coordinate system
The axes of the body coordinate system are permanently connected to the vehicle, usually to the chassis. The X axis points in the positive direction of travel. The origin of the body coordinate system is identical to the origin of the ADMA measuring axis coordinate system.
Note: The axis alignment of the body coordinate system can be changed in the configuration of the ADMA. There are two alignment variations available:
• classical Navigation (SAE)
• DIN ISO 8855:2013 (DIN70000)
The horizontal (levelled) coordinate system
The axes of the horizontal coordinate system are aligned in such a way that the XY axis level is orthogonal to the acceleration of gravity vector (in the horizon), the X axis alignment is identical to that of the body coordinate system, and the Z axis is parallel to the vector of the gravitational. As with the body coordinate system, the origin of this coordinate system is identical to the origin of the ADMA measuring axis coordinate system.
The frame coordinate system
The frame coordinate system is also known, respectively to the alignment, as the NED coordinate system (North-East-Down). Just as the horizontal coordinate system, the XY axes level is orthogonal to the acceleration of gravity vector.
The axes of the reference coordinate system are defined as follows:
• X axis points positive to the north
• Y axis points positive to the east
• Z axis points positive down
Coordinate Systems Overview
Output options for the body and the horizontal coordinate system
The ADMA allows defining the output for all horizontal and referenced coordinate systems via Webinterface configuration. There are the following options:
| The classical (Navigation / SAE) • right-handed Cartesian coordinate system • System’s X axis points in the vehicle’s direction of travel • System’s Y-axis points rightward • System’s Z axis points downward • Direction of rotation by the positive axis direction follows the “right hand rule” |  |
| The coordinate system according to DIN 70000 • right-handed Cartesian coordinate system • System’s X axis points in the vehicle’s direction of travel • System’s Y-axis points leftward • System’s Z axis points upward • Direction of rotation by the positive axis direction follows the “right hand rule” |  |
ADMA coordinate system origin
All calculated inertial data of the ADMA like position absolute, position relative and velocity refer to the ADMA coordinate system origin. This is the measurement origin of the ADMA accelerometers.
The added signals for augmentation (GNSS data and external velocity) are each transformed with an individual set of lever arms to the ADMA coordinate system origin, so they can be fed into the Kalman filter.
For checking which data channels relate to which coordinate system please see the article Coordinate Systems of ADMA data channels.
