1. A method of high-resolution direction finding to an arbitrary even order, 2q (q>2), for an array comprising N narrowband antennas each receiving the contribution from P sources, wherein the algebraic properties of a matrix of cumulants of order 2q, C 2q,x (l), whose coefficients are the circular cumulants of order 2q, Cum[x i 1 (t),. .. , x i q (t), x i q+1 (t)*,. .. , x i 2q (t)*], of the observations received on each antenna, for cumulant rankings indexed by l, are utilized to define a signal subspace and a noise subspace.