GB793606A - Improvements in or relating to aircraft supervisory radar installations - Google Patents

Abstract

793,606. Radar. TELEFUNKEN GES. April 10, 1956, No. 10892/56. Class 40 (7). Relates to a radar system for determining the elevation or height of an aircraft and the position of the aircraft along an air route, said sys. tem comprising a plurality of pulse radars spaced along said route, each radar comprising a fan-shaped beam, shown in elevation and plan in Figs. 3 and 4, respectively, which is scanned in the vertical plane containing the route. In such a system accurate values of elevation are obtained only if the horizontal angular deviation of the craft from the centre of the route does not exceed a predetermined value # and if the lateral width of the route is x then this condition obtains for aircraft at the edge of the route only when the distance r of the craft from the radar is greater than x/2tan# ~ x/2#. According to the present invention each radar is made unresponsive to echoes from craft within an initial region 4, Fig. 3, of range r, and the radars are arranged so that the ineffective region 4 of one radar is covered by the effective region 5 of another radar. Fig. 5 shows an arrangement comprising two terminal radars 7, 17 and two pairs of intermediate back-to-back radars 9, 11 and 13, 15, the ineffective and effective regions of each radar being of equal magnitude so that the regions 10, 8, 14, 12, 18 and 16 are covered respectively, by radars 9, 7, 13, 11, 17 and 15. In Fig. 6 the ineffective region of each radar is half the length of the effective region so that the regions 23, 24, 25, 26 are covered by radars 19, 21, 20, 22, respectively. Any two adjacent radars, e.g. 9 and 11, Fig. 5, may utilize a common trigger pulse generator or common transmitter. The echoes are displayed by intensity modulation of a C.R.T. range-elevation sector display, Fig. 8, the virtual origin of the display-being offset so that the horizontal range display corresponds to the effective region. Such a local display may be reproduced at a central station by known methods or the radar data may be transmitted direct to the central station. The azimuthal position of the craft relative to the centre line of the route may be determined by using two overlapping beams, Fig. 7 (not shown), or by beam switching, the signals received in the two beam positions being applied to separate C.R.T. displays of the type shown in Fig. 8.