Radio transient detection in radio astronomical arrays

Celestial transient radio sources have attracted considerable scientific interest recently, but their investigation is hampered by the fact that they cannot be effectively detected by commonly used radio astronomy imaging techniques. One significant obstacle to observing radio transients is intermittent terrestrial radio frequency interference, which can appear as a transient signal. In this paper we propose two schemes for the detection of transient sources. The first is a generalized likelihood ratio test designed for terrestrial interferences that appear in the near field region. The second is a modification of the first one, designed for sources whose steering vector is known to be in the array manifold, such as astronomical sources. Both of the proposed detectors are based on two consecutive sample covariance matrices computed by the array, and they have the desirable property of a constant false alarm rate. We provide a simple analysis of the proposed method as well as a computer simulation. The computer simulation results suggest that the proposed detectors outperform the detector that is currently used by the low frequency array (LOFAR) radio telescope processor.