GB1071268A - Guidance systems for vehicles and the like - Google Patents

Abstract

1,071,268. Photo-electric guidance systems. OFFICINE GALILEO S.p.A. Dec. 2, 1963 [Dec. 11, 1962], No. 47398/63. Heading H4D. A vehicle is guided by directing an optical radiator beam to a receiver in the vehicle, part of the beam is modulated alternately at a frequency F 1 and a frequency F 2 , the whole beam is amplitude modulated at a reference frequency # 0 and the receiver compares outputs at frequencies F 1 and F 2 and at frequencies F 1 and # 0 to afford control signals which tend to maintain the vehicle on a fixed path with respect to the beam. The embodiment relates to the guidance of a missile by a beam from the ground, frequency F 2 being F 1/2 hereafter termed f. The modulation at frequencies f, 2f is effected by a rotating reticle carrying two series of radial slits one series having twice the number of slits as the other (Fig. 2, not shown); at the receiver the outputs at the two frequencies are compared after amplitude equalization and rectification to give a radial-error signal. The reference signal is produced by a disc which is half transparent and half attenvating, the disc being rotated at a predetermined rate with respect to that of the reticle; at the receiver the reference signal phase is compared with that of the signal of frequency 2f after rectification of the latter to give an angular-error signal. The missile is stabilized against rotation about its own longitudinal axis. Optical and electric frequency filters may be added.