Aim To extract harmonic frequencies of helicopter acoustic signal as features for hel icopter identification. Methods Estimation of signal parameters via rotational invariance techniques(ESPRIT) was selected to extract harmonic frequencies from really measured helicopter acoustic signal and an algorithm based on the SVD TLS was used. Results ESPRIT correctly extracted harmonic frequencies of helicopter using the data of limited length under the variousflight conditions. Conclusion ESPRIT is an effective method of extracting harmonic frequencies and using harmonic frequencies of helicopter acoustic signal to recognize helicopter is feasible.
Being aimed at the weakness of short range target′s threshold value recognition system,the double passage And Gate recognition system was put forward on the correlativity of target signals and randomness of noise signals Through state analysis and inference of state transition probability,both the reliability and early burst probability of the system were obtained in theory
