Rover Orientation Data, Where can one find detailed rover orientation data? Options

[CosmicRocker]

I am trying to quantify Spirit's final resting orientation, but I would generally like to learn how to determine the orientation of either rover for any particular sol. I'm sure this data is in the MMB files somewhere, but I haven't been able to identify it. Likewise, I am sure it is somewhere in the Analyst's Notebook database and/or the Pancam data tracking database, but again, I can't find it.

Spirit's final orientation is the main thing I am looking for, but any orientation assistance would be greatly appreciated.

Thanks.

[Deimos]

A few thoughts on the IMU/QFA issue ...

- The IMU is used whenever there is mobility. It tracks changes in attitude, by which I mean the vector or quaternion describing the rover's orientation (not just one element of said vector). The QFA or GFA (get fine attitude, which takes longer and is not quick) is run when the inertial measurement needs updating. The Sun measurements are critical to this.

- The Sun imaging in the QFA/GFA is not just a single image. It is a set. Position of the Sun in one image gives you two pieces of information (direction of the Sun, for instance in rover frame azimuth and elevation). Imaging over time gives you two more (d_az/d_t, d_el_dt). They are not fully orthognal, but are enough to populate roll,pitch,yaw or a quaternion (the quaternion is 4 numbers, but they quadratically add to 1, so only 3 degrees of freedom). A long IMU integration ensures that the attitude is over-determined. The orientation of the Sun in the frame is not determinable, except from infeerence based on motion.

- The frames of reference are the rover body frame and local level (i.e., areoid). I doubt the difference between "orthoganal to gravity" and "orthoganal to the radius vector" add up to much at either MER site.

- Time is actually part of the error budget, and affects the derivation from Solar images but not IMU. You couldn't refine longitude with solar imaging, since time knowledge can drift by up to 30 sec between corrections, and there are PMA-related uncertainties on top of that.

- The attitude is updated every time the IMU is used. A QFA/GFA updates the site. A drive does not end with the same attitude as it starts with. Those changes are tracked with the IMU, reported in the images, and used to point the HGA at Earth. This happens many times per QFA.

- The last quaternion I see, sol 2209, is [0.885949, -0.169903, 0.0031267, -0.431529] (Doug's). For that I get a tilt of 19.6 deg WSW, yaw=309 (51 W of N) pitch=-8.1 (nose down), roll=17.7 (+Y/right-hand panel up). So that's pretty close to what James got, no surprise there.