Patent GB-658759-A (GB)
Title: Arrangement for transmitting signals for automatically controlling the deviations of flying bodies from a prescribed path
IPC: F41G7/24
Filed: 1948-08-05
Abstract: 658,759. Radio navigation. PATELHOLD PATENTVERWERTUNGS- & ELEKTROHOLDING AKT.-GES. Aug. 5, 1948, No. 20689. Convention date, Aug. 14, 1947. [Class 40 (vii)] In an arrangement for the automatic control of the deviation of flying bodies, such as aircraft approaching to land or projected missiles, from a prescribed flight path, in which radio waves are radiated in accordance with a club-shape beam, the main radiation direction of which is subjected to a rotational movement about a conical surface, means are provided at the transmitter for marking with interruption impulses a predetermined momentary position of the rotational movement of the beam. At the receiver, the low-frequency modulation imparted by the conical scanning motion is derived to provide a first oscillation the amplitude and phase of which are proportional, respectively, to the lateral and angular displacement of the body from the axis of the conical scan, and a second oscillation is derived from the interruption impulses to provide a reference oscillation of fixed phase, the first and second oscillations serving to actuate apparatus controlling the deviation of the body. Conveniently the interrupting impulse occurs when the main radiation direction passes through the perpendicular plane from the conical scan axis to ground. In the receiver, Fig. 4, the highfrequency oscillations e1 from antenna 2 are rectified in stage G, the low-frequency signals thus obtained being amplified in controlled amplifier V. The low-frequency signals have the form shown in Fig. 3b in which the time t# corresponds to the phase displacement between the modulation maximum Hmax and the interrupting impulses Ju, and is proportional to the angle between the position of the body and the reference position defined by the impulses. The degree of modulation Hmax - - Hmin is a measure of the lateral displacement of the body. The output voltage e4 from the amplifier passes to a peak rectifier circuit AD where the impulses Ju are separated from.the modulation and serve to control an oscillator Osc to produce an output oscillation u2 of fixed phase and amplitude as regards the impulses. The impulse voltage e6 also passes through a low-pass filter TP and acts as a gain control voltage for the amplifier V to maintain the output constant. The oscillator may be controlled by using the locking effect, or a control voltage e8 may be obtained by modulating the oscillator output u2 with the impulse voltages e6 in stage M. The modulation component of the amplifier output is extracted by amplitude filter AS, the threshold level of which may be automatically adjusted to the input level by a control voltage e9 derived from a rectifier GR connected to the filter output, and band-pass filter BP, the output oscillation u1 corresponding in amplitude and phase to the modulation Hmax - Hmin. The oscillations u1 and u2 are applied to control the deviation of body automatically, the lateral displacement being obtained by measuring the amplitude of oscillation u1 and the angular displacement by measuring the phase difference between oscillations u1 and u2. The flight axis may be a straight path or one varying during flight so as to follow a prescribed curved path.