Superresolution of multiple noise sources in antenna beam

The superresolution of external noise sources that lie within the beamwidth of an adaptive array antenna becomes increasingly more difficult as the number of sources and corresponding number of antenna subapertures are increased. This difficulty was demonstrated with a digital computer simulation of a particular array antenna that utilizes Gabriel's thermal noise algorithm to accomplish the superresolution processing. Two closely spaced sources are easily resolved when the antenna is divided into three subapertures. It is not as easy to resolve four sources when the antenna is divided into five subapertures, and it is especially difficult to resolve six sources when the antenna is divided into seven subapertures. When the sources are not completely resolvable, however, the two outermost sources in the cluster are accurately located in many instances, and at least precise bounds on the cluster are established.