METHOD FOR RECOGNIZING TYPE OF SINGLE AIR TARGET FROM AIRCRAFT WITH TJE CLASS Russian patent published in 2023 - IPC G01S7/41 G01S13/52 G01S13/53 

FIELD: radar.

SUBSTANCE: used to recognize the type of aircraft with a turbojet engine (TJE) in a pulse Doppler radar station (radar). In the claimed method, the radar signal reflected from an aircraft with a TJE is subjected to narrow-band Doppler filtering and converted into an amplitude-frequency spectrum (AFS), the spectral components of which are caused by reflections of the signal from the airframe of an aircraft with a TJE and the rotating blades of the impeller of its low-pressure compressor (LPC) power plant. By threshold processing of the AFS signal, only those Doppler frequency samples F_i with the corresponding amplitudes of the spectral components that exceed the set threshold are formed. Simultaneously, during the time T of each space survey, two values of the D₁ and D₂ distance to the aircraft with a TJE are measured and the frequency position of the Doppler frequency F_p is calculated, depending on the speed of approach of the pulse Doppler radar carrier with the airframe of the aircraft with a TJE. The position of the Doppler frequency signal with the maximum amplitude of the spectral component exceeding the set threshold is determined in the AFS, which corresponds to the value of the Doppler frequency F_c, determined by the speed of approach of the pulse Doppler radar carrier with the rotating blades of the first stage of the pressure booster of the aircraft power plant with a TJE. Calculate the Doppler frequency difference ΔF_nk = (F_n – F_k). During the time T of each spatial survey, the values of the onboard bearings of azimuth and elevation are measured, from which, as well as from the average range D, the altitude and, additionally, the flight speed of the aircraft with a turbojet engine are calculated. For each altitude H and flight speed V of an aircraft with a TJE, the a priori range of differences ΔF_nk are divided into Q of non-overlapping subranges. When hit by a difference in Doppler frequencies ΔF_nk in the q-th sub-subrange, a decision is made about the q-th type of aircraft with a TJE, flying at altitude H with speed V.

EFFECT: increasing the reliability of recognition of the type of aircraft with a turbojet engine in a pulse Doppler radar station when it flies at various altitudes and speeds.

1 cl, 4 dwg, 1 tbl