I don't believe it's gonna work... But not for some of the reasons in this thread.
To get a true honest AOA I would think flight testing and calibration would be make/model specific as well as dependent on what STC's are installed. STOL kits, VG's, gross weight increases (reduced flap limits) would all need careful evaluation.
It has to be, and is, calibrated on the particular airplane it's installed on. STOL kits and all of the other stuff you mention would require a recalibration. But, that's not the problem.
No, not on how it computes. Where it gets its source data from.
With no new hardware, we know what is available to it.
If we wanted to speculate on how they compute, it's likely going to be some variation on a Kalman filter. Which is exactly what it should be.
It's in the pilot's guide. The first sentence of section 4.1.1 is: "The Aspen ADAHRS attitude solution uses inputs from its internal three-axis
accelerometers, rate gyros, and magnetometers, supplemented by ram and static air pressure inputs from the aircraft pitot-static system."
All modern GA glass cockpits use solid-state accelerometers and gyroscopes along with Kalman filtering to do what they do.
Varies from plane to plane though. Even on the same make and model. Also, - think icing.
Icing shouldn't be a problem. As you ice up and you need to pitch up to increase your AoA to compensate, the Aspen can easily sense that you're still traveling in the same direction but you have an increased pitch attitude. That's how it's measuring AoA to begin with.
I would have to disagree with you on this. It has attitude data, speed data, 3D data (WAAS source), so there is no reason why the computer cannot figure out an exact angle of attack... especially when it is calibrated.
It has any data available that a hardware solution would have.
No, it doesn't. The hardware solutions rely on a vane (high-end, like on jets) or a differential pressure sensor. The Aspen does NOT have ANY of the data available that a hardware solution has.
The main problem with how they're apparently doing it is that it cannot correct for vertical air movements.
Will it work in an updraft/downdraft?
NO. And that is the problem.
They can quite easily determine the difference between flight path and where the nose of the aircraft is pointed. That makes for an easy solution in straight and level flight in still air.
They can also easily determine load factor with the onboard accelerometers to account for AoA in non-straight and level flight.
It's the "still air" thing that's the problem. Vertically moving air will result in a different pitch for the same flight path. It's not impossible to calculate this with all of the inputs - Including gross weight and engine power - But those inputs are not available to the Aspen and thus it cannot be correcting for vertically moving air.
It's not worthless, but like any other aircraft system, you do have to understand its limitations.
