GB909900A - Recording system - Google Patents

Abstract

909,900. Aircraft radar gun-sights; cathoderay tube displays. NORTH AMERICAN AVIATION Inc. Dec. 4, 1959, No. 41358/59. Class 40 (7). [Also in Group XXXIII] Relates to a pulse radar fire and flight control system for a fixed gun fighter aircraft in which the azimuthal and elevational components of the deviation of the aircraft heading from a desired pursuit course is indicated by the horizontal and vertical displacements of a luminous error spot 18 from the centre of a luminous reference circle 21 on the screen of a cathode-ray tube, the " time-to-go," i.e. the time that must elapse before the guns are fired, is given by the radius of a luminous " time-to-go " circle 20 as indicated by a time scale 20b, the rate of change of distance between the fighter and target is given by the circumferential position of a gap 20a in the circle 20 as indicated by an outer annular speed scale and the bank of the aircraft is indicated by the angular position of a luminous horizon line 19; the radius of the reference circle may also decrease as the time-to-go decreases. According to the present invention the pairs of x and y deflection voltages producing the error spot 18, the time-to-go circle 20, the reference circle 21 and the horizon line 19 are applied sequentially to the deflection circuits of the cathode-ray tube by means of relays controlled by a chain of three multivibrators, Fig. 6 (not shown), the electron beam is normally cut off and is intensified during the various deflection signals by corresponding intensity gating signals and the sequential x deflection, y deflection and gating signals are recorded on three separate channels on a magnetic tape driven by a motor which is energized only when echo signals are received from the target, Figs. 7, 8 and 9 (not shown). The recorded signals may then be subsequently reproduced to analyse the engagement. The range of the target is indicated by the vertical position of a deflection pipe on a vertical range trace 22 as given by the left-hand fine or right-hand coarse range scales and the azimuthal displacement of the target from the aircraft heading is indicated by the horizontal displacement of the range trace 22 from the centre of the screen. The range trace 22 is preferably produced continuously by applying the appropriate deflection signals to deflection members controlling a second electron beam of the cathode-ray tube and a D.C. range signal is converted to A.C. by chopping and filtering and is then recorded on a fourth channel on the magnetic tape, Fig. 9 (not shown). The range rate, time-to-go and steering error signals are derived, Fig. 1 (not shown), in a known form of computer from the radar range and the azimuth, elevation, azimuthal rate and elevational rate of the aerial automatically tracking the target; the steering error signals are then modified in accordance with the pitch and roll of the aircraft.