GB1525835A - Augmented perspective radar display - Google Patents

Abstract

1525835 Perspective radar D W YOUNG 25 May 1976 [28 May 1975] 21623/76 Heading H4D A perspective radar system, such as that of USA Specifications No. 3,778,821 and No. 3,896,432, has its display 39 augmented so as to provide a display 40 in perspective as it would appear if the observer were at a different position from his actual position. This different position may be in altitude, in range, or a combination of both. The sweep wave form voltage function applied to the vertical input 32 of the cathode ray tube display 15 is modified to correspond substantially to that which would be generated if the radar antenna 17 were at such a different position. This is done by manual control of a synchronizing pulse delay circuit 19, inserted between the radar pulse repetition frequency trigger signal generator 18 and the transmitter 20, and/or of a simulated altitude generating circuit 36 connecting into the altitude control circuit 35 which feeds into the sweep and control circuit 25. The radar may be incorporated in aircraft or ships. The antenna 17 transmits radar pulses in the form of a fan-shaped beam 13 lying in a vertical plane and scanning in azimuth over angles # from a centre position. Echo signals pass through video amplifier 23 to input 33 of display 15. An electron beam is moved horizontally back and forth across the screen in precise synchronism with the movement of beam 13 by the signal generated from the position sensor 28, passed through horizontal amplifier 29 to horizontal input 31. The same electron beam also sweeps from the bottom to top of the screen at a rate controlled by the sweep wave from voltage function received in vertical input 32 from vertical amplifier 26 and circuit 25. The vertical sweep frequency is many magnitudes higher than the horizontal movement of the antenna beam and electron beam. The echo signals in the form of video signals at input 33 modulate the beam so that the brightness of the screen fluorescence increases in proportion to the strength of the video signal so that the various targets are displayed on the screen. The real altitude signal from box 34 is fed to circuit 25 to render the display in perspective. The sweep in the vertical direction changes with time in the form of a hyperbolic function, the specific shape of which is determined by the altitude, Fig. 4 (not shown).