3rd French conference on acoustics
J. Phys. IV France 04 (1994) C5-1339-C5-1342
Détection d'hélicoptères par analyse du bruit acoustique rayonné par leur rotor principalM. PECOT1, G. VEZZOSI2 and F. EHRMANN2
1 Thomson-CSF/LER, Avenue de Belle Fontaine, 35510 Cesson-Sévigné, France
2 LTSI, Université de Rennes I, Campus de Beaulieu, 35042 Rennes cedex, France
This paper describes a technique for the detection of helicopters based on the farfield acoustic signal produced by their main rotor. This signal may be well modelled as that produced by a point-like rotating source with periodic excitation. The corresponding harmonics may be computed analytically, which allows to define a receiver using both the modulus and the phase of the measured harmonics. Such a receiver may then be considered as a variant of the matched filter, which improves detection capabilities and allows for some rough classification of the detected signal.
© EDP Sciences 1994