Detection and estimation of an unknown narrow-band signal in severely nonstationary noise

The problems of detection and estimation of an unknown narrowband signal in a severely nonstationary interference environment are addressed. The interference is viewed as a stochastic process n(m,t) in two variables (m representing the sensor, and t the time); if t is fixed the corresponding process is stationary but if m is fixed it is nonstationary. A uniform linear array is assumed, and it is also assumed that the carrier frequency is known and that the direction of arrival (DOA) of the desired signal does not change. The detection problem is discussed for a known DOA, and it is shown that it is a constant false alarm rate (CFAR) detector. The approach taken here is an application/extension of the multiwindow method for spectrum estimation and harmonic analysis introduced by D.J. Thomson (1982). How the signal is estimated if present and how to estimate the DOA are briefly discussed