Abstract: The accurate estimation of direction of arrival from measurements contaminated by noise is important for improving performance of some application system. Although estimation of signal parameters via rotational invariant techniques has good performance in scenarios of high signal to noise ratio, when signal to noise ratio is low, its performance degrades dramatically. In this paper, the measurements of the array are preprocessed with maximal overlap discrete wavelet transform. The noise power is reduced, so the performance of conventional algorithm of estimation of direction of arrival is improved for real application scenarios. The digital simulation results verified the validity of the new algorithm.