Extended array method for detection and direction finding of a weak linear frequency modulated signal

A well known computationally efficient method for parameters estimation of linear frequency modulated (LFM) signals is to mix the received signals with a shifted version of itself. The drawback is the dominating cross terms in low signal to noise ratio scenarios. In this paper we present a novel technique for the detection/estimation of a weak LFM signal using an array of receivers which can strongly suppress these cross terms. The technique is to take the tensor product of the received signal vector with a delayed version of itself. This approach results in the extended array signal model. The Bayesian approach to the joint direction of arrival (DOA) and chirp rate detector/estimator is derived based on this extended array signal model. We demonstrate the interference suppression abilities of this approach using simulations.