Array processing application: angular superresolution for scanning antenna

Step-scanned radar antennas represent a new application of radar technology for detection of targets and estimation of their locations. Processing of radar data from scanning antennas involves techniques that are similar to linear array antenna processing techniques. In particular, an extension of the well-known multiple signal classification (MUSIC) algorithm is applicable; however, it requires some modifications. This paper describes a new development called scan-MUSIC (SMUSIC), which extends the application of the MUSIC algorithm to the resolution of closely spaced targets with a step-scanned radar. This paper also demonstrates that SMUSIC can be used with radar data obtained with an experimental coherent scanning radar. The results show that targets that are spaced less than 1/4 of the antenna beamwidth and are interfering can be resolved with SMUSIC under some circumstances. A new approach for determining the limit of the resolvability of two targets as a function of the relative phase of their coherent returned signals, without going through the whole process of computing the SMUSIC pseudo-spectrum, is also presented.