Borgelt Dynamis variometer

On the mems devices if you have played with them, are pretty standard.

Compasses have errors. The 3 axes are not always at 90 degrees. The center is not necessarily at 50%, and each axis may be scaled differently. It's quite straight forward to turn this ellipsoid into a unit sphere. That's just the calibration.

Same applies for accelerators. You can rotate and hold still to get the calibration.

Gyros are odd. They suffer the same but they drift over time, so you need to adjust for the drift. But over a short period they are good.

GPS is accurate certainly over long periods.

From what I know, TE and ASI, along with altimeters are noisy measuring devices. Noise changes pressure, and hence you get a random change in altimeter. Not sure how they are affected by temperature.

So what do you want to measure?

1. The orientation of the glider - bank, pitch and direction
2. It's velocity
3. It's acceleration
4. The vector of the air. Wind speed + vertical
5. Conceivably, slip.

6. Flaps
7. Conceivably even the control movements.

That should give you a good model, and you should be able to fit from that.

It is what the AHRS systems use anyway, for a subset. See the Madwick system

http://x-io.co.uk/open-source-imu-and-ahrs-algorithms/