Thomson-csf

Claude De Volder

Michel Wybierala

Alain Bourdeau

Daniel Barbier

Jean-Paul Parissenti

Didier Creveau

Lionel Largilliere

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.

Pulse recognition method and device, and use thereof for the filtering

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.

Method and device for the filtering of responses in a secondary radar

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.

Method and device to improve the probability of validity of the codes of

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.

Method and device to detect the garbling of pulses received by a

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.

The device improves the decoding of the replies in S mode deformed by multiple-path phenomena or by imbrication with replies in standard A or C mode. To do this, the device carries out the following in the reception video signal Log .SIGMA. of the secondary radar: determines a pulse level reference value of the data block of the reply by a study of the histogram of the presumed pulse levels of data and compares the level of the reception signal Log .SIGMA. taken at the middle of each time interval that may be occupied by a data pulse with the level reference value, a data pulse being detected or not detected according to the result of the comparison. Should there be a negative result in a baud period, it may recommence similar operations on the angle measurement video signal .SIGMA./.DELTA. if the secondary radar is a monopulse radar.

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Auffargis, France

Claude De Volder