Isn't it true that the AGC was initially designed to be the sole navigation computer, but when the implementation did not meet the requirements for accuracy (due to accelerometer and gyroscope drift), they switched to a ground-based radar system? This meant the AGC became the back-up in case the communications system failed. Does anyone know if the AGC was ever used to make a mission-critical decision in the absence of the ground-based radar system?
Edit: I think it was actually the PGNCS that was made back-up [1]. Sorry the comment about Kalman filter had me confused. Apparently PGNCS was still used for maintaining orientation, controlling rockets, and navigation during planned outages.
Edit: I think it was actually the PGNCS that was made back-up [1]. Sorry the comment about Kalman filter had me confused. Apparently PGNCS was still used for maintaining orientation, controlling rockets, and navigation during planned outages.
1: http://en.wikipedia.org/wiki/Apollo_PGNCS