Coordinate Frames and Notation

Coordinate Frames

Rovio makes use of various coordinate frames:

• W: the inertial coordinate frame employed by the EKF.
• M: the coordinate frame attached to the IMU
• C: the camera coordinate frame (optic center, z is along camera axis, x/y span image plane, x right, y down)
• V: Reference body coordinate frame if external pose measurements are employed
• I: Reference inertial coordinate frame if external pose measurements are employed

Notation

• qAB: represents the quaternion rotating a vector from coordinate frame B to A, JPL-convention
• ArAB: represents the coordinate of a vector from A to B expressed in coordinate frame A