In satellite-to-helicopter communications, interference exists on the incoming signal when the receiving antenna is located below the rotor blades. A bound is established for the performance of a coherent fixed-tone ranging system operating at L band in this interference environment. The scalar diffracted field beneath the rotating blades, at L band and above, is found to satisfy the criterion of Fresnel diffraction, and is computed using the techniques of Fourier optics. The diffracted field is expressed in terms of a narrow-band signal. The amplitude and phase components are calculated from a Fourier Series expansion using the FFT algorithm. The significant harmonics of the phase component of the interference combine with the baseband of the narrow-band, phase-modulated ranging signal. This results in CW interference, and in rearrangement of the first-order, sideband, ranging-tone channel powers. The degradation in ranging accuracy is evaluated by computing the signal-to-interference (SIR) ratio for a set of ranging tones. The post-detection (SIR)PD at the output of the correlator is shown to be a function of the amplitude of the phase harmonics of the interference, the relative difference between the ranging tone and interference center frequencies (a function of rotor speed), the rangetone modulation indices, and the post-detection filter noise bandwidth.


    Zugriff

    Zugriff prüfen

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    An Analysis of Helicopter Rotor Modulation Interference


    Beteiligte:
    Kadar, Ivan (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    01.05.1973


    Format / Umfang :

    1898906 byte




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



    Near-Field Analysis of Helicopter Rotating Blades Modulation Interference

    Moaveni, Mahmood K. / Mohseni, Mahmood | IEEE | 1979


    ROTOR HEAD OF HELICOPTER, MULTI-ROTOR TYPE HELICOPTER AND HELICOPTER

    UEHORI TAKAKAZU / SUZUKI SHUNICHI | Europäisches Patentamt | 2017

    Freier Zugriff

    HELICOPTER ROTOR

    PETROV VASILIJ SILANTEVICH | Europäisches Patentamt | 2018

    Freier Zugriff

    HELICOPTER ROTOR

    NEKRASOV VLADIMIR IVANOVICH | Europäisches Patentamt | 2017

    Freier Zugriff

    HELICOPTER ROTOR

    Europäisches Patentamt | 2017

    Freier Zugriff