GB1224992A - Gyroscopic north seeking device - Google Patents

Abstract

1,224,992. Gyroscopic apparatus. COMPAGNIE DES COMPTEURS. Aug.21, 1968 [Aug.21, 1967], No.40073/68. Heading G1C. A gyroscopic compass comprises a gyrometer 2 with a horizontal spin axis suspended on a wire 1, the gyroscope carrying a disc 6 for rotation therewith about the axis of the wire 1 the disc having two diametrically opposed graduated scales co-operating with two photo-electric pick-up devices 3, 3A so as to generate a signal in the form of a number of pulses responsive to the angular position of the gyroscope, electrical circuitry being provided for repetitively calculatingfrom the signal numbers which are functions of the period of oscillation of the gyroscope about the meridian, and the angular deviation between the axis of symmetry of these oscillations and a reference direction defined by a photo-electric device 5B co-operating with a black/white or opaque/transparent transition line on the disc 6, the derived angular deviation being indicated on a panel. In use the gyro-rotor spin axis is set approximately in alignment with the meridian and the period of oscillation of the gyroscopic is measured by counting the number of pulses from a timing clock (not shown) occurring between successive passages of the transition line on the disc 6 past the photo-electric device 5B in the same direction, this number of pulses being compared with the number previously measured on with a number set into the apparatus dependent on the latitude. This output is divided to obtain the half-period of oscillation and is indicated on the panel and also used to control a gate circuit to allow a further counter to count and algebraically add the number of pulses derived from the graduated scales on the disc 6 detected by the devices 3, 3A for one half-period of each complete oscillation. From the algebraic sum the misalignment between the gryo spin axis mean position and the gyroscope housing can be determined and this is indicated on the panel. Electrical circuitry for effecting the necessary calculations is described in the specification. The gyroscope may be caged when not in use by rotating a knob 7 to raise a plate 10 and clamp the disc 6 between it and a further fixed plate 11.