Abstract: A system for aircraft landing light alignment which includes a target of photocells distributed in a cross-like manner with a single photo detector centered about the common point of the cross-like distribution. A signal processing circuit coupled to the output of the target includes electronic readout devices distributed in a cross-like manner for indicating which way the beams should be directed to provide correct light adjustment. The aircraft landing light alignment system includes signal processing of photo detector derived signals which measures only the outer fringes of the Gaussian beam distribution.

Abstract: A method for determining proper operation of a multi-section photo-sensitive detector (10) includes measuring (102) the cathode-anode dark resistance of each section and rejecting the detector (104, 108) if any section measures less than a predetermined value or if the ratio of the dark resistance of any section to the section having the highest dark resistance (106) exceeds a specified level. Each detector is also subjected to anode-to-anode or cathode-to-cathode dark resistance testing for both adjacent (110) and non-adjacent (124) sections, with testing based on comparisons between section pair readings and the sum of the cathode-anode dark resistances of each section in the tested pair (114, 128).