For DOA estimation of uncorrelated signals

a minimum cost function is presented

and it is based on the diagonal covariance matrix of uncorrelated signals in beamspace.And DFT matrixes are introduced as beamforming matrixes.By matrix transform

the influence of beamforming matrix is overcome

and the Vandermonde structure of array manifold is kept.With the structure characteristic

the cost function is transformed to a quadratic function.Then accurate estimations can be easily achieved.Simulation shows that the proposed algorithm can provide accurate estimation efficiently

with lower resolution threshold.