Blind source detection and separation using second order non-stationarity

We address the problem of using an array of sensors for detecting a narrow band source and separating its signal from unwanted disturbance signals, that is jammers and noise. The power of the desired signal is assumed to move from one level to another. This second order non-stationarity occurs, for instance, in frequency hopping systems, and more generally, at the beginning or at the end of any communication. We derive a method based on the generalized eigenstructure of two covariance matrices which requires no a priori knowledge of the array manifold, but only second order stationarity of the disturbance signals. The loss in signal to interference plus noise ratio (SINR) due to finite sample effect is calculated in closed form at the first order and validated by simulations. This last result shows that the method gives interesting performance in a wide range of situations.