Abstract
Estimating the number of sources impinging on an array of sensors is a well known and well investigated problem. Based on the rotational invariance property between two identical subarrays, using the Lanczos algorithm to fast compute the analysis filterbank of multi-stage wiener filter, a novel method for fast estimating the number of wideband sources is proposed in this paper. Unlike the traditional number estimator, the new method does not require an estimate of the covariance matrix or its eigen-decomposition, so it avoids computationally intensive eigen-decomposition and the complexity is greatly decreased. The computer simulations show the availability and efficacy of the method.