And about what Boeing thinks the AOA sensor does ( dated approx year 2000 )
Aero 12 - Angle of Attack
he U.S. National Transportation Safety Board (NTSB) has recommended visual indication of AOA in commercial airplanes. This indication may take the form of a dedicated AOA indicator or other implementation, such as the PLI. A dedicated AOA indicator shown on the primary flight display (PFD) recently has been developed in cooperation with airline customers. The new indicator is offered as an option on the 737-600/-700/-800/-900, 767-400, and 777 at this time. During the development of the new indicator, discussions with airlines, the NTSB, and U.S. Federal Aviation Administration (FAA) pilots and engineers provided a unique opportunity to examine potential uses of AOA and the many existing uses that have evolved in recent decades along with advances in display and indication technology.
...
The indicator developed shows body AOA in degrees and is not normalized, which is related to the second objective above, that the indicator be useful when pitot or static data, and therefore Mach calculations, are unreliable because of blockage or a fault in the system. The pointer of a normalized indicator in this condition would behave erratically, making the indicator unusable. With the nonnormalized design, the position of the needle is a function only of sensed AOA. The red tick mark for stall warning may behave erratically in a pitot or static failure state, as may stick shaker, PLI, and speed tape amber and red bands. However, the AOA needle and digits will remain stable, and the indicator itself still will be useful as a backup for unreliable airspeed, provided the AOA vanes are undamaged.
I think the whole document is worth rreading now !!