Patent ID: 7084812

Claim:
A method for estimating the directions of cyclostationary signals, comprising the steps of: forming L overlapping forward subarrays with {overscore (q)}(≧q) antenna elements, where M antenna elements are linearly placed with a same element spacing, and q is the number of desired signals; forming a cyclic correlation matrix from the cyclic correlations between the received signals of L forward subarrays and a received signal of a predetermined antenna element, and dividing the cyclic correlation matrix into two upper and lower submatrices; calculating an orthogonal projection operator in the noise subspace by performing a linear operation from two upper and lower cyclic correlation matrices; and calculating a spatial spectrum or a polynomial by using the estimated orthogonal projection operator and estimating the directions from of the position of q highest peaks of the spatial spectrum or the phases of q roots of the polynomial closest to the unit circle in z-plane.