16.2. Technical Description
The instrument mount models are essentially a statically or dynamically computed affine transforms that are applied to the rays that emerge from the instrument. This transform is comprised of a translation that represents the relative location of the instrument on the platform and a set of rotations that captures the platform relative pointing of the instrument. The order of these operations is the platform relative pointing rotations (see Platform Relative Pointing) and then the platform relative location translation (see Platform Relative Location). The resulting mount transformed rays emerging from the instrument and mount combination will then be further translated and rotated by the affine transform resulting from the platform location and rotation relative to the scene (see Platform Modeling).
16.2.1. Platform Relative Pointing
Each mount model has some set of axis relative rotations that are applied. In some cases, they may be fixed and in other cases they change as a function of time. Some models have non-zero rotations for each axis, and some for only 1 or 2 of the axis. In any case, the individual matrix rotation transforms are defined using right-handed angles about the primary coordinate axes as follows:
The nominal instrument pointing location is straight down out of the aircraft or satellite bus:
16.2.2. Platform Relative Location
At this time, the mount model interfaces do not support platform relative location of the instrument. This will be enabled in a future release when multiple instruments can be configured on a single platform.