GB1535943A - Airport surface traffic control system - Google Patents

Abstract

1535943 Radio navigation INTERNATIONAL STANDARD ELECTRIC CORP 23 April 1976 [25 April 1975] 16660/76 Heading H4D An airport surface traffic control system is expanded from a known landing system, wherein the landing aircraft radiates interrogating pulses containing an identification signal for the aircraft and in which the directions of arrival of the pulses are determined by an azimuth- and an elevationmeasuring unit 6, 7, guidance information is transmitted from a transmitter to the aircraft, and indicated there, whereby after touchdown the coordinates of the position of the aircraft 10 are determined, compared with the coordinates of a reference point 5, and the result used to provide coarse taxiing guidance information which is transmitted to the aircraft in coded form, is decoded and indicated therein. Additional azimuth-measuring units 8, 8a, 8b, co-operate with azimuth-measuring station 6 of the landing system to measure the directions of arrival of the interrogating pulses, and the aircraft coordinates are calculated in a central station 9 in known manner by a process computer or by an existing air-trafficcontrol computer, Markings 4 which indicate paths to be followed by the aircraft are provided on the runway 1, taxiways 2 and parking places 3, and bifurcations in these markings act as the reference points 5. A cross-pointer instrument 31, 32, indicates the coarse taxiing guidance information on board the aircraft, the horizontal pointer 31 moving towards the datum marks 37 as the aircraft approaches the bifurcation 5 and the vertical pointer 32 indicating that the aircraft is to turn right at this point. If pointer 32 were between marks 36 this would indicate that the aircraft was to taxi on straight ahead. Fine taxiing guidance for the aircraft is provided by a television camera on the aircraft directed towards the runway and producing an image of the markings 4 on a screen 33, the markings coinciding with datum marks 36 when the aircraft is directly above them. The area of the image shown is adjustable as a function of taxiing speed. An alternative embodiment uses radio-active markings and a Geiger-Mueller counter tube instead of a television camera. The image appears on screen 33 only after a switch has changed over from the mode "landing" to the mode "taxiing guidance". This enables the same cross-pointer instrument 31, 32 to be used to indicate the azimuth and elevation during landing, although a separate indicating instrument may be used. Taxiing instructions such as "stop", "wait" or "go on" can be given via signal lamps 35, or audibly, and the distance to be travelled to the bifurcation at which the aircraft has to turn off is indicated at 34.