A secondary radar equipped with an electronic-scanning antenna with active or semi-active emission regime, covering space azimuthally over 360°, characterized in that said radar: - 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; - has one or more SSR / IFF interrogators dedicated at one and the same time to SSR or IFF surveillance and to gathering new mode S targets; - further contains one or more other SSR / IFF interrogators for selective surveillance dedicated to mode S surveillance and to directed interrogations of IFF identification; - ensures the simultaneous emission of the interrogations of said SSR / IFF interrogators in different azimuths , said 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 received by the respective sidelobes of the beams formed in emission; - ensures simultaneous reception of the replies to said interrogators in different azimuths , said simultaneous reception being enabled when the azimuthal spacing of the beams formed in reception ensures a decoupled level of jamming at the level of the radar between the replies expected by the respective sidelobes of the beams formed in reception; - instructs the interrogators to ensure amongst themselves the temporal separation of either the emission or reception periods when the spacing of the beams in azimuth is insufficient to guarantee detection. - 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; ∘ 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; - has one or more SSR / IFF interrogators dedicated at one and the same time to SSR or IFF surveillance and to gathering new mode S targets; - further contains one or more other SSR / IFF interrogators for selective surveillance dedicated to mode S surveillance and to directed interrogations of IFF identification; - ensures the simultaneous emission of the interrogations of said SSR / IFF interrogators in different azimuths , said 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 received by the respective sidelobes of the beams formed in emission; - ensures simultaneous reception of the replies to said interrogators in different azimuths , said simultaneous reception being enabled when the azimuthal spacing of the beams formed in reception ensures a decoupled level of jamming at the level of the radar between the replies expected by the respective sidelobes of the beams formed in reception; - instructs the interrogators to ensure amongst themselves the temporal separation of either the emission or reception periods when the spacing of the beams in azimuth is insufficient to guarantee detection. <EOS>