An ADS-B transponder system is associated with a vehicle including a transponder. The system includes a universal access transceiver (UAT) subsystem configured for detecting and responding to an interrogation signal by broadcasting a signal representing a vehicle parameter. The interrogation signal can be detected by monitoring current fluctuations in a power bus on the vehicle. The UAT subsystem is connected to a smart antenna configured for transmitting and receiving ADS-B signals. In an aircraft (A/C) application the vehicle parameter can comprise squawk code, altitude, heading vector, airspeed and other flight data.

A mode S Interrogation Side Lobe Suppression System (ISLS) for an electronically scanned interrogator is described. One aspect introduces the 90 phase offset between the main and control beams thereby enabling the full power capability of the TRU to be effectively utilized and the effective beamwidth in Mode S to be sharply defined. The system allows the transmission of the simultaneous ISLS pulse of a Mode S all-call interrogation to be transmitted using the same array as is used by the main beam.

A method and system for controlling message transmission power implemented by a system for preventing collisions of aircraft during flight, the prevention system comprising an anti-collision device and a transponder with which each plane is equipped. There is a step for measuring at least the quality value of a quantity representative of the quality at which radio-frequency signals carrying response messages transmitted by a transponder of an intruding aircraft are received, and a step for controlling the power of transmission of the radio-frequency signals carrying the response messages depending o the quality value or values measured in this way.

A method for detecting a plurality of useful signals in a total signal. The useful signals correspond to radiofrequency signals emitted by different terminals in a multiplexing frequency band. A plurality of spectrograms calculated that have a compensated linear frequency drift and are respectively associated with different linear frequency drift values. For each analysis frequency and each spectrogram, time envelope filtering of the values is performed at the different times for analyzing the spectrogram at the analysis frequency using a filter representing a reference time envelope of the useful signals. A useful signal is detected at an analysis time and at an analysis frequency in response to a verification of a predefined detection criterion by the value from a spectrogram resulting from filtering at the analysis time and at the analysis frequency.

Various avionics systems may benefit from appropriate integration of distance measurement equipment and traffic collision avoidance systems, or the like, using an omnidirectional antenna. A system can include an avionics processor. The system can also include a top antenna receiver configured to connect to a top antenna. The avionics processor can be configured to communicate using the top antenna. The system can further include a bottom antenna receiver configured to connect to a bottom antenna. The avionics processor can be configured to communicate using the bottom antenna. The bottom antenna can be an omnidirectional antenna. The system can additionally include a distance measure equipment receiver configured to be connected to the bottom antenna. The system can also include a distance measure equipment processor configured to measure distance using the bottom antenna.

A a method for managing a secondary radar operating in Mode S, the method includes a) a detection in seeking mode, the seeking mode being implemented until an aircraft is detected by the secondary radar; b) a detection in tracking mode, the tracking mode being implemented if a valid response to a roll-call interrogation was detected in seeking mode; the method comprising an intermediate step a1), which is executed between the detection in seeking mode and the detection in tracking mode, the intermediate step comprising: detecting the presence or absence of the reply of the aircraft in a noise window of the secondary radar; carrying out at least one roll-call interrogation, using the first monitoring window, if the reply of the aircraft is not located in the noise window.