GB759609A - Apparatus for deriving navigational data in radio beam control systems - Google Patents

Abstract

759,609. Electric aircraft indicators. AKTIEBOLAGET WIESING. Aug. 5, 1953 [Aug. 29, 1952], No. 21644/53. Class 40(1) [Also in Group XL(c)] In a system for enabling a pilot to make an asymptotic approach to a flight path defined by azimuth and elevation overlapping-beam equi-signal beacons, the displacement of an indicating member from a reference position is controlled by generating a first control signal comprising the algebraic sum of three signals proportional respectively to the angular displacement of the aircraft from said path, the first time derivative of said displacement and the rate of turn of the aircraft, integrating said first control signal to give a second control signal and applying to the indicator either said second control signal only, Fig. 2, or both said first and second control signals, Fig. 4 (not shown). In such a system the rate-of-turn signal is substantially proportional to the second time derivative of said displacement, the first control signal is proportoinal to errors in the rate of turn and the second control signal in proportional to heading error. As shown signals proportional to the angular displacement produced in the receiver 1 are applied to a displacement indicator 2 and to the input of a servo system 4 comprising an amplifier 3 controlling a motor 5 which automatically positions the slider of a potentiometer 7 so that the voltage between said slider and the fixed centre tap is proportional to the displacement, the input to the motor being then proportional' to the first derivative of the displacement. These two signals are applied to coils 11 and 12 to produce a torque proportional to their resultant which is balanced against the processional torque of a rate-of-turn gyro 8 whose axis 9 controls the setting of a potentiometer 10 to produce the first control signal which is applied through an amplifier 14 to energize an integrating motor 15 controlling the position of the slider of a potentiometer 16 to give the second control signal which actuates the indicator 17. Stops 18 are provided to limit the magnitude of the displayed signal. In a modification, Fig. 4 (not shown), the first and second control signals are applied to a differential indicator the relative amplitude of the two signals being adjustable. When used for azimuthal control the gyro 8 may be inclined so that its torque output is proportional to azimuth rates of turn and to the rate of change of the roll angle, the relative effect of the two components being controlled by adjusting the inclination of the gyro.