METHOD OF AIRCRAFT TYPE IDENTIFICATION WITH TURBOJET ENGINE IN PULSE-DOPPLER RADAR STATION UNDER ACTION OF SIMULATING NOISE

摘要

FIELD: physics.;SUBSTANCE: invention relates to the field of secondary processing of radar signals and can be used for recognition in an impulse-Doppler radar station of the aircraft type with a turbojet engine (TJE) under action of imitating (distance and speed) interference. In the method, a signal reflected from an aircraft with a jet turbine engine is subjected to narrow-band Doppler filtration and converted to an amplitude-frequency spectrum. Further, in the first Kalman filter, estimating the Doppler frequency caused by reflections of signal from aircraft airframe, in second Kalman filter is estimated Doppler frequency caused by signal reflection from advancing blades, and in fourth Kalman filter from aircraft first stage low-pressure compressor first stage impeller turbo blades. Differential derivative difference estimator is compared between estimated values of Doppler frequencies with threshold value ε, close to zero, and decision is made on presence or absence of action of speed-escaping interference. In the third Kalman filter, a difference module is compared between the estimate of the range derivative to the aircraft and the estimate of the speed of approach of the radar station with the accompanying aircraft with the threshold ε1, the difference module between the range estimate and the calculated range D*(k) - with the threshold ε2. Depending on the results of comparison with threshold values, a decision is made on the presence or absence of the effect of intervening speed and range noise with/without a functionally related law. Entire range of possible values of estimates of differences is divided into Q non-overlapping subranges depending on the value of rotation speed of the rotor of the power plant, calculating probability P_q of falling of value in each of formed q-x subbands. Maximum value of probability is compared with threshold value, and at P_qmax ≥ P_thr decision is made on recognition of q-type aircraft with turbojet engine with probability P_qmax not lower than specified.;EFFECT: technical result is recognition in pulse-Doppler radar station with probability not lower than the specified type of aircraft with turbojet engine at effect of interruptions in range and speed of interference.;1 cl, 4 dwg