GB591019A - Improvements in or relating to remote indicating compasses - Google Patents

Abstract

591,019. Magnetic tests and measurements. HUDSON, C. S. April 13, 1945, No. 9328. [Class 37] In a remote indicating compass for aircraft, ships, &c., the two components of the earth's magnetic field are obtained irrespective of the position in space of the magnetic elements of the compass. As shown, four sine-cosine potentiometers 1, 2, 3, 4 are employed with centre-tappings and brush connections and electromagnetic pick-ups adapted to be rigidly attached to the craft, are used to produce currents proportional to the three components of the earth's field along the vertical, pitch and roll axes of the craft. These currents are fed respectively to potentiometers 1, 2, 4 and by means of a vertical gyroscope the potentiometer brushes 11, 12, 13, 14 are operated in accordance with the angle of roll of the craft and brushes 15, 16 in accordance with the angle of pitch. The resultant currents proportional to the two required horizontal components are transmitted to amplifiers 22, 23 so as to produce signals in the coils 18, 21, positioned as shown, to give a compass heading on the indicator 19 corresponding to the vector sum of the two currents. In an alternative arrangement (Fig. 2, not shown), three induction regulators are used with their input field windings connected to the pick-ups and their rotors operated by the gyroscope in accordance with the angle of pitch and roll so as to induce currents in the rotor windings proportional to the two required horizontal components.