Abstract: An array antenna to be mounted on curved portions of satellites, airplanes, ships, land moving objects, or the like, in which a base (31) on which a plurality of antenna elements (34) are arranged and a radome (36) for covering the plurality of antenna elements (34) are formed to be curved so as to coincide with the curved surface configuration of a wall body (47) or the like on which the antenna is to be mounted to thereby structure the entire antenna to be low in height while securing the strength thereof.

Abstract: When a beam is formed in a direction at a switching point of microstrip array panels, two microstrip array panels associated with the switching point are used and a phase shift due to arrangement of the panels is compensated by a pre-set phase shifter so that sufficient gains can be secured for omni directions including boundary directions of the array panels in which very small gains have been obtained previously.

Abstract: A power supply system adapted for an array antenna to be mounted on satellites, airplanes, ships, land moving objects, or the like, which is so arranged that a cylindrical member (136) is provided at a peripheral edge part of an opening (135) formed on a wall member (134) on which the antenna is to be mounted, a group of power supply lines (143) connected to a group of power supply connectors (124) are disposed in an interior of the cylindrical member (136), and the space between the interior of the cylindrical member (136) and the group of power supply lines (143) is sealed by an adhesive (146), thereby securing the air-tightness and water-tightness.

Abstract: A collision avoidance system using on-board B-CAS equipment having an object to minimize interference with the ground SSR stations and to effect precise tracking or distance-altitude measurement when necessary. Normally passive surveillance is made to detect the presence of other aircraft in the B-CAS range. Active surveillance is added when required. In the active surveillance mode, initiated on locating an intruder aircraft, the power and interrogation signal are varied when the intruder aircraft becomes a threat aircraft to minimize interference with the ground SSR stations and aircraft outside the threat zone while maintaining accuracy of detection and tracking of the threat aircraft at a high level.

Abstract: A collision avoidance system for aircraft using an on-board beacon interrogator. If altitude information is not included in a response signal from a transponder of an other aircraft or the response signal is garbled because a plurality of other aircraft are responding to the same interrogation signal, the system automatically switches to a beacon based proximity warning system and indicates the distance or other indication to the detected aircraft.

Abstract: A bearing detection system used in an Airborne Collision Avoidance System. The detection end of the system is formed as a directional antenna having 3 directional antenna elements extending radially at a 120.degree. angle with each other. The antenna element has an actual length corresponding to .lambda./8, wherein .lambda. is the wavelength of the receiving wave, but the element has an effective length corresponding to .lambda./4 by the provision of an impedance matching plate and a back lobe suppression plate. Bearings of the incoming wave can be detected by means of relative strength of the receiving signal levels of the three antenna elements obtained by amplitude comparison and by forming 3 bit truth table for six directions including the 3 directions of the antenna and 3 boundary directions thereof by the strength of the receiving signal received by the three antenna elements.

Abstract: A collision avoidance system for aircraft in which one aircraft is equipped ith an interrogation station having a secondary surveillance radar. Coarse distance measurement is effected either by passive or active distance measurement or by both of them. If the detected distance lies within a certain limit, the output power and/or period of the interrogation signal of the secondary surveillance radar of the subject aircraft is altered so as to effect fine distance measurement. This system can be applied without increasing interference against the existing secondary surveillance radar system by keeping the output power and period of interrogation signal in a minimum required extent. By the same reason the system can keep the interference at a small extent between proximate aircraft, each mounting this collision avoidance system.

Abstract: A collision avoidance system for aircraft in which one aircraft is equipped with an interrogation station having a secondary surveillance radar. .[.Coarse.]. .Iadd.A .Iaddend.distance measurement is effected either by passive or active distance measurement or by both of them. If the detected distance lies within a certain limit, the output power and/or period of the interrogation signal of the secondary surveillance radar of the subject aircraft is altered .[.so as to effect fine distance measurement.].. This system can be applied without increasing interference against the existing secondary surveillance radar system by keeping the output power and period of interrogation signal in a minimum required extent. By the same reason the system can keep the interference at a small extent between proximate aircraft, each mounting this collision avoidance system.