Abstract: In order to improve the success probability of number estimation of signals in the presence of color
noise, an Otsu method based on pseudocovariance matrix is proposed. The pseudocovariance matrix composed of
delay correlation of array output signals is immune to white Gaussian noise and colored Gaussian noise under
certain conditions. The array’s effective aperture is improved by using the time correlation between arrays, and
then the differences between signal singular values and noise singular values, which are obtained from the
singular value decomposition of pseudocovariance matrix, are also improved. And by utilizing Otsu method to
classify the signal singular values and noise singular values, the probability of successful estimation of source
number is further improved.

Key words: estimation of the number of signal, array signal processing, pseudocovariance matrix, Otsu class variance