Detection-estimation of more uncorrelated Gaussian sources than sensors in nonuniform linear antenna arrays - part III: detection-estimation nonidentifiability

For pt.II see ibid., vol.51, no.6, p.1492-507 (2003). We investigate nonidentifiability conditions for the detection-estimation problem with multiple uncorrelated plane waves incident upon a nonuniform (sparse) linear antenna array. Specifically, we define conditions under which a given Hermitian covariance matrix has a nonunique (multiple) decomposition into an admissible number of dyads weighted by the source powers and a white-noise identity matrix. Our method is based on the Proukakis-Manikas technique of generating ambiguity generator sets (AGSs) and allows ambiguous sets of sources associated with a given sparse antenna geometry to be determined.