Patent ID: 6184830
Filing Date: 2001-02-06
Classification: G01S,H01Q

Abstract:
An interferometric method for estimating the angle of arrival of a signal from a source, using an antenna array having antenna elements with arbitrary orientation, where each element has an orientation .alpha..sub.n relative to some reference element, and each element has a measured complex voltage of v.sub.n =M.sub.n e.sup.j.PSI..sub.n, the method comprising:computing the measured powers {p.sub.n } and the measured phases {.PSI..sub.n } from the measured complex voltages of {v.sub.n };using the measured powers {p.sub.n } and {.alpha..sub.n }, solving for a polarimetric ratio .zeta.;using .zeta., computing a set of estimated polarimetric phase components {{character pullout}}; andusing the corrected phase measurements {.PSI..sub.n -{character pullout}}, solving for the angle of arrival .OMEGA.;wherein the polarimetric ratio is defined by .zeta.=bd/ac, the polarimetric vectors e.sub.n of the antenna elements represented with eigenvectors e.sub.R and e.sub.L, the right-hand circular and left-hand circular basis set, the polarimetric vector e.sub.1 for the first element is expressed in terms of this basis set as:e.sub.1 =ae.sub.R +be.sub.L, where a and b represent unknown complex scalars, and the polarimetric vector of the source is expressed as:e.sub.T =ce.sub.R +de.sub.L, where c and d are unknown complex scalars; andwherein the set of estimated polarimetric phase components {{character pullout}} is defined as:{character pullout}=arg((exp(j.alpha..sub.n)+.zeta.exp(-j.alpha..sub.n)) (1+.zeta.).sup.-1).