frame that is fixed with respect to the gyro external optical cube where and whose origin is defined unambiguously with reference to the gyro external optical cube
NOTE 1 The X, Y and Z axes of the ARF are a right-handed orthogonal set of axes which are defined unambiguously with respect to the normal of the faces of the external optical cube. Figure 3-1 schematically illustrates the definition of the ARF.
NOTE 2 If the optical cube’s faces are not perfectly orthogonal, the X‐axis can be defined as the projection of the normal of the X‐face in the plane orthogonal to the Z‐axis, and the Y‐axis completes the RHR.
NOTE 3 The ARF is the frame used to align the sensor during integration.
NOTE 4 This definition does not attempt to prescribe a definition of the ARF, other than it is a frame fixed relative to the physical geometry of the sensor optical cube.
NOTE 5 This term is defined in the present standard with a different meaning than in ECSS-E-ST-60-20. The term with the meaning defined herein is applicable only to the present standard.