Polarization-independent angle of arrival determination system using a miniature conformal antenna

1. A miniature conformal polarization-independent antenna, comprising:

a cavity having a mouth and located in a conductive substrate;

quadrature antenna elements at the mount of said cavity;

a phasing module coupled to the feed points of said elements for measuring the right hand circular polarized component and the left hand circular polarized component of a signal at said antenna; and,

a unit within said module for calculating the angle of arrival of a wave incident on said antenna by measuring the right hand circularly polarized components and the left hand circularly polarized components of the wave and for generating an angular correction factor compensating for the polarization of the incoming wave, the angular correction factor being derived from the right hand circularly polarized components and the left hand circularly polarized components of the wave incident on said antenna and the electronic rotation of said antenna, said angular correction factor being a function of the complex amplitude difference in the outputs of pairs of said antenna elements.

2. The antenna of claim 1 , wherein said angular correction factor is derived from a plot of said amplitude difference as a function of angle.

3. The antenna of claim 2 , wherein said angular correction factor is derived from curve fitting with said plot.

4. The antenna of claim 3 , wherein a correction factor F is derived from said curve fitting.

5. The antenna of claim 4 , wherein said angular correction factor is a phase angle associated with F.

6. The antenna of claim 1 , wherein said quadrature antenna elements are triangular in shape.

7. The antenna of claim 6 , wherein said triangular elements are fed at the apex of the element.

8. The antenna of claim 7 , wherein opposed pairs of said triangular elements form dipoles, and wherein the direction associated with said antenna is determined by addressing selected dipoles and processing the outputs therefrom.

9. A method for compensating a cavity embedded conformal antenna having quadrature elements at the mouth of the cavity so as to provide a polarization-independent angle of arrival and measurements, comprising the steps of:

obtaining angle of arrival from measured right hand circularly polarized and left hand circularly polarized components of a wave incident on the antenna; and,

correcting the angle of arrival to remove polarization-dependent anomalies, the correcting step including the step of electronically rotating the direction which the antenna is sensitive to and addressing and processing selected antenna elements, the antenna being sampled at a number of different directions to form an amplitude difference between pairs of elements and selected angles of arrival to the antenna so as to form a curve, the correcting step including utilizing the curve for deriving a correction factor to remove polarization-dependent anomalies.

10. The method of claim 9 and further including deriving elevation utilizing the outputs of the elements.

11. A low visibility miniature conformal polarization-independent antenna, comprising:

a cavity imbedded antenna having quadrature elements, pairs of which form dipoles; and

a phasing module coupled to said antenna elements for deriving angle of arrival from right hand circularly polarized and left hand circularly polarized components of a signal incident on said antenna and for correcting polarization-induced errors by using the right hand circularly polarized components and the left hand circularly polarized components from said elements and electronic antenna rotation to provide an angular correction so that the azimuthal angle of arrival determined by the right hand circularly polarized components and left hand circularly polarized components has polarization-induced errors removed, said angular correction being a function of the complex amplitude difference in the outputs of pairs of said antenna elements.