1. Apparatus for determining angular misalignment between a desired aim point and an actual aim point of a missile or other vehicle, comprising memory means for prestoring at least three related signals representing the appearance of the aim point area at an initial range and at successively closer ranges to such aim point, scanning means for generating a current signal indicative of the area about the actual aim point, and means for sequentially utilizing the prestored signals in determining angular misalignment between the current signal and the memory signals.