1. A method of source number estimation, comprising: (1) obtaining signals X(t) received by a uniform linear array, X(t)=[x 1 (t), x 2 (t),. .. , x M (t)] T is an M×1 vector, where x 1 ,. .. , x M represent signals received by elements from 1 to M in said uniform linear array, and t represents time; (2) calculating the covariance matrix {circumflex over (R)} X according to the received signals; (3) conducting eigendecomposition to {circumflex over (R)} X to obtain its eigenvector matrix U C [q 1 , q 2 ,. .. q M ], where q i is eigenvector of {circumflex over (R)} X , q i [q 1i , q 2i ,. .. , q mi , q Mi ] T , i=1, 2,. .. , M; and (4) calculating a source number m according to the q i .