GB1311308A - Method and apparatus for aircraft guidance - Google Patents

Abstract

1311308 Radio navigation SOC DE FABRICATION D'INSTRUMENTS DE MESURE 3 July 1970 [11 July 1969] 32409/70 Heading H4D In an automatic landing system, particularly for use by a helicopter, a ground transmitter E, Figs. 1, 2 produces a radio wave at 10 to 20 gigahertz which defines a landing path R. A receiver D, Fig. 3, on the aircraft, detects the radio wave and derives therefrom a signal G proportional to the vertical misalignment of the aircraft from path R. A signal L, proportional to the horizontal deviation of the path R, is similarly produced. Accelerometer A V , Radio Sonde S, anemometer V, control T, accelerometer A L , respectively produce:- VZ the vertical velocity component, a gain control dependent on the aircraft's altitude and distance from the transmitter, the indicated airspeed Vi, a control speed Vc, and the horizontal velocity component dV L /dt. The aircraft is vertically controlled by the pitch control H 1 , receiving, via the altitude section P 1 of an automatic pilot P, a signal K 1 G+K 2 dG/dt+K 3 Vz. Coefficients K 1 and K 3 are respectively produced by amplifiers 1 and 3 whilst differentiator 2 produces K 2 dG/ dt. The weighted signals are combined at the input to a limiter 4 used to control the maximum pitch variation to within safe limits. The aircraft is horizontally controlled by a roll control H2 and a course control H3 receiving, via respective roll and yaw auto pilot sections P 2 and P 3 , a signal K 4 L + K 5 dl/dt. The K 4 L and K 5 dL/dt signals from respective amplifier 7 and differentiator 8 are combined at limiter 9 having a safety limit which decreases when the altitude is less than a predetermined value. A pitching altitude control H 4 is fed with a signal K 6 (Vi-Vc) + K 7 dV L /dt from comparator 10 and circuit 11, via maximum safety value limiter 12 and a signal #K 6 (Vi-Vc)dt from integrator 13.