Abstract: To solve the problems of the narrow-band signal DOA method, such as low resolution and unsuitable for applications with small number of snapshot and array elements, etc, DOA of uniform circular array based on improved smoothed l₀ norm was proposed after analysis of the characteristics of UCA model and signal airspace sparse, combining with improved the smooth l₀ norm algorithm. For reconstructing the signal, the method used the combined continuous function as the approximation to l₀ norm by sparse matrix processing array manifold, which improved the convergence speed. It was also extended to the UCA DOA estimation, which avoided feature decomposition and spectral peak searching process. On the premise of guarantee the estimation precision, the calculation and the number of the array were effectively reduced. The feasibility and effectiveness of the method were verified by the experimental simulation.

Key words: narrow-band signal, uniform circular array, DOA, space sparsity, improved smoothed l₀ norm