ML estimation of SSR signals, identifiability, and Cramer-Rao Bounds

In this article, a Maximum Likelihood method is applied to Secondary Surveillance Radar (SSR) signals impinging on an M-element antenna. At base-band, a SSR signal consists of a binary signal with alphabet {0,1} multiplied by a complex exponential. Identifiability is proved in this binary case, and specific Cramer-Rao Bounds are derived and assessed.