초록 ▼

A method and apparatus of deriving a directional polar diagram from the signals R received by a synthetic-aperture aerial (in direction-finding applications), or P from such an aerial (in radio-beacon applications), these signals including a carrier of frequency wwm of the individual aerials. The me

A method and apparatus of deriving a directional polar diagram from the signals R received by a synthetic-aperture aerial (in direction-finding applications), or P from such an aerial (in radio-beacon applications), these signals including a carrier of frequency wwm of the individual aerials. The method comprises generating an “estimated”signal (26) of frequency wwm, and multiplying (25) the generated signal by the received signal to derive an output which includes a selectable Bessel Function (JO) representing the directional polar diagram. The phase (with circular aerial arrays) (27) or amplitude (with linear aerial arrays) of wm as applied to phase-modulate the generated signal is controlled to maximize or minimize, as appropriate, the selected Bessel Function and thereby control the bearing direction of the polar diagram. The zero-order Function JO gives a lobe maximum in the bearing direction, the higher orders, J1, J2, etc. a lobe null. The phase difference between wwx.

대표청구항 ▼

A method of processing signals received from one of a synthetic-aperture aerial from an external radiator and a synthetic-aperture aerial at an external position, which is phase-modulated at the scanning frequency of said aerial, comprising: generating a signal of the same carrier frequency as the r

A method of processing signals received from one of a synthetic-aperture aerial from an external radiator and a synthetic-aperture aerial at an external position, which is phase-modulated at the scanning frequency of said aerial, comprising: generating a signal of the same carrier frequency as the received signal and phase-modulated at the scanning frequency; multiplying the generated signal by the received signal to derive an output which includes a selectable Bessel Function representing a directional polar diagram; and controlling one of the phase and amplitude, based upon the aerial configuration, of the scanning frequency, as applied to produce said phase-modulation of the generated signal, in order to maximise or minimise, as appropriate, a selected Bessel Function and thereby control the bearing direction of said polar diagram relative to the aerial.