Detection of tones and pulses using a large, uncalibrated array

A problem of growing interest in radio astronomy is that of how to detect transient astronomical signals over a wide field of view (FOV). Two classes of signals of particular interest are ultra-narrowband tones, which are sought in SETI and wideband pulses associated with gamma ray bursts and intermittent "giant pulses" from pulsars. A useful method to detect weak signals over a wide FOV is to use an array consisting of elements whose patterns are individually broad enough to cover the entire FOV, yet which can be processed together to achieve the sensitivity of a large, fixed-aperture antenna. The optimal detection algorithm for such a system requires a search over all possible directions of arrival, This paper presents a suboptimal approach that avoids the need to calibrate the array, but is robust to noise covariances which are spatially or spectrally non-white. The tone-detection version of the algorithm is described followed by a study of performance and computation burden. A pulse-detection version of this algorithm is outlined.