Abstract: A microwave deviation measurement receiver particularly applicable to airborne secondary radars making deviation measurements with two logarithmic amplifiers which increase the reliability of deviation measurements for targets close to the direction of aim of the radar. A programmable phase shifter preferably is controlled to compensate for aircraft movements by shifting the phase of the sum or control signal.

Abstract: An air navigation and landing aid system wherein a pair of transponder beacons are located at known positions adjacent an airport runway. The aircraft carries a weather pulse radar system and an antenna for furnishing information affording a navigation aid during the flight stage. Switching means are inserted between the antenna and the weather radar for switching, during the landing stage, the received pulses relating to each beacon, in response to the interrogation of the weather radar, to a special receiver and a processing circuit which furnishes information affording a landing aid.

Abstract: The invention relates to side-looking radar systems and more especially to high altitude airborne radar systems functioning at a high repetition frequency. In order to avoid ambiguities in regard to distance, the antenna comprises an additional channel which has a radiation pattern which has an odd symmetry about its axis and means are connected to said antenna for deriving the angular interval relative to the axis of the antenna of the direction of the obstacle corresponding to the received echoes. Gating means select the angular interval signal at the middle of the recurrence, for controlling the recurrence frequency of the radar and maintaining the ambiguous areas outside the selected observed area.