METHOD OF AIRCRAFT WITH TURBOJET ENGINE TYPE IDENTIFICATION IN PULSE-DOPPLER RADAR STATION

摘要

FIELD: radar ranging.;SUBSTANCE: invention relates to the field of radar ranging and can be used for recognition in a Pulse-Doppler radar of aircraft type with turbojet engine (TE). Method of aircraft type identification with TE in pulse-Doppler radar station consists in the fact that radar signal reflected from aircraft with TE, from the output of the receiver of the radar station at an intermediate frequency is subjected to narrow-band Doppler filtration based on the fast Fourier transformation procedure and is converted to an amplitude-frequency spectrum (AFS), which spectral components are caused by reflections of signal from airframe of aircraft with TE and rotary blades of impeller of low pressure compressor (LPC) of its power plant, by threshold processing of AFS signal only those Doppler frequencies are formed, which have exceeded the set threshold, during time T of each space survey, two distance values D₁ and D₂ to aircraft with TE, from which frequency position of Doppler frequency , caused by speed of approach of radar station carrier with airframe of aircraft with TE, in AFS signal closest to pre-calculated frequency position of Doppler frequency . Doppler frequency value with corresponding amplitude spectral component, which exceeds the established threshold, which finally determines Doppler signal frequency F_n in its AFS, determined by the speed of approach of the carrier of the radar station to the airframe of the aircraft with the TE, the position of the Doppler frequency (j=1, …, (i-1), (i+1), …, N), on which there is a spectral component which has exceeded the threshold and having a maximum amplitude A_j (j=1, …, (i-1), (i+1), …, N), which corresponds to Doppler frequency value F_k, due to the speed of approach of the radar station carrier to the LPC first stage rotary blades of aircraft powerplant with the TE, the Doppler frequency difference is calculated ΔF_nk=(F_n-F_k), a range of differences is divided a priori ΔF_nk on Q non-overlapping q subbands corresponding to the q-th type of the target, when the difference of Doppler frequencies falls ΔF_nk decision on q-th type of aircraft with TE is made in q-th subrange.;EFFECT: high reliability of aircraft type identification with TE.;1 cl, 4 dwg