Frame rotation

Introduction

One main functionality of irfpy is frame conversion. Many third party functions are available (e.g. spice), but still it is needed to implement by oneself in order to

• understand frame characteristics by handling ourselves

• simple extension without help of third party persons

• access to conversion functionality in a unified way

Indeed, the second one is most important for me, because for new missions or conceptional missions, there are usually no such aids from others.

Anyway, most of the conversions have been done mission-based way (indeed this statement contradicts to the third benefit…), but still some functionalities can be standard-nized.

One example of standard access necessity is found in yaw-pitch-roll angles.

Yaw-Pitch-Roll

Consider an aircraft. The elevation angle is pitch. The rotation around the centeral axis of the body (wings are in up-and-down motion) is roll. The rotation around the up-down axis is yaw.

There are no “common” definition of the x-y-z coordinate system correlated to the yaw-pitch-roll axis. Also, the sign of these angles are not very clearly defined. As far as I understand, they are “defined” for each case.

Anyway, good picture can be found here: http://en.wikipedia.org/wiki/File:Rollpitchyawplain.png

Considering the above conditions, I now give up (2013-03-25) to make a generic routine for “yaw-pitch-roll” module.