Abstract: A radar is provided which is mechanically and functionally independent of the primary radar; applies the principles of separation of emission pattern for each interrogation of any mode; of reception pattern for each reply of any mode; of assignment of the tasks which are specific thereto to distinct units. The radar includes one or more SSR/IFF interrogators dedicated at one and the same time to SSR surveillance and to gathering new mode S targets; and includes one or more other SSR/IFF interrogators for selective surveillance dedicated to mode S surveillance and to directed interrogations of IFF identification. The radar ensures simultaneous emission of the interrogations of the SSR/IFF interrogators in different azimuths, this simultaneous emission being enabled when the azimuthal spacing of the beams formed in emission ensures a decoupled level of jamming at the level of the transponders of the aircraft between the interrogations emitted by the respective sidelobes of the beams formed in emission.

Abstract: A radar is equipped with a main antenna having three radiation patterns, sum, difference and control, corresponding to the antenna, the radar comprises an auxiliary antennal device, composed of an antenna and of a rear radiating element which is situated at the rear of the antenna, fixed above the antenna and coupling means, the auxiliary antennal device: having three radiation patterns, sum, difference and control, the control pattern ensured for the direction opposite to the antenna by the rear radiating element; the antenna inclined to guarantee a maximum gain of its sum pattern in the elevational domain (60°-90°).

Abstract: A method for the real-time management and sequencing of the information interchanges between a secondary radar and a plurality of aircraft includes the interchanges between the radar and a given aircraft being performed, depending on the aircraft concerned, either in a non-selective, SSR, IFF or “All Call” interrogation mode or in a selective “Roll Call” interrogation mode. According to this method, the information interchanges according to the non-selective interrogation modes are performed during successive periods specifically allocated to these modes, whereas each transaction forming an information interchange in selective mode between the radar and a given aircraft is temporally inserted into the time slots not used in periods by the interrogation-response tasks in non-selective mode. The method applies equally to the secondary radars exclusively dedicated to civilian air traffic control and to the secondary radars dedicated to combined civilian and military aircraft control tasks.

Abstract: A method for the real-time management and sequencing of the information interchanges between a secondary radar and a plurality of aircraft includes the interchanges between the radar and a given aircraft being performed, depending on the aircraft concerned, either in a non-selective, SSR, IFF or “All Call” interrogation mode or in a selective “Roll Call” interrogation mode. According to this method, the information interchanges according to the non-selective interrogation modes are performed during successive periods specifically allocated to these modes, whereas each transaction forming an information interchange in selective mode between the radar and a given aircraft is temporally inserted into the time slots not used in periods by the interrogation-response tasks in non-selective mode. The method applies equally to the secondary radars exclusively dedicated to civilian air traffic control and to the secondary radars dedicated to combined civilian and military aircraft control tasks.

Abstract: The present invention applies to the surveillance of, in particular civil, air traffic, and more particularly, to cooperative aircraft ground systems which make it possible to pinpoint in radial distance and in azimuth the aircraft present in a certain volume and to interrogate them. The invention makes it possible to determine a reference value of a response contained in a reception signal of a secondary radar, doing so even in the presence of strong pollution, in particular in the event of nesting between mode S responses.

Abstract: Disclosed are a device for the detection of S mode responses received by a secondary radar receiver and its use for the filtering of the pulses contained in this response. The device furthermore comprises means to detect a signal S, means for the real-time computation of the mean values of magnitudes characterizing the pulses that belong to the response, and means for the filtration, by comparison, of the values of the magnitudes measured on each pulse detected with the mean value of the corresponding magnitude.

Abstract: A method for the defruiting of the responses from radar transponders received by a secondary radar in response to interrogations sent by the radar recurrently, a recurrence being formed by the interrogation and the responses received during a listening period that follows the interrogation, the defruiting operation consisting in verifying that a response received at an instant T of the recurrence is correlated by the presence of at least r-1 other responses received at the same instant T of their recurrence, these responses forming part of a sequence of at least r recurrences including the current recurrence, the method being one wherein the correlation is achieved over several chosen sequences and wherein the correlation is declared to be positive if it is positive for one of the sequences.

Abstract: Disclosed are a method and device for the real-time processing of the responses constituted by pulse signals emitted by secondary radar transponders. The device has an analyzer of sampled magnitudes characterizing the pulses, said magnitudes being prepared by a device located upline with respect to the disclosed device. This device creates a sample message at the sampling rate. Said sample message characterizes the variations of the different magnitudes from one sample to another. A device for the processing of the pulses receives the sample messages and prepares pulse messages. Finally, a device filters the pulses belonging to a same response from the information elements pertaining to the pulse messages and from response detection signals.

Abstract: In a method for the detection of the garbling of pulses received by a secondary radar, the secondary radar comprises a monopulse antenna that can be used to obtain a pulse power signal and a pulse difference measurement signal synchronous with the received pulses. The method consists in detecting, at the same time, ripples superimposed on the power signal and ripples superimposed on the difference measurement signal, the presence of at least two garbled pulses being detected by the presence of ripples on at least one of the two signals. Application to the reception circuits of secondary radars.

Abstract: Disclosed are a method and a device to detect the intermingling, hence the garbling, of pulses received by a secondary radar by phase analysis. The monopulse reception antenna of a secondary radar delivering a sum signal given by its sum channel and a difference signal given by its difference channel, the method according to the invention consists in analyzing the phase difference between the sum signal and the difference signal, the garbling of at least two received pulses being detected by a phase difference with a value that is substantially different from 0.degree. or 180.degree.. Application to the detection of garbled pulses received when the working frequencies of the transponders are very close to one another.