On the Maximal Invariant Statistic for Adaptive Radar Detection in   Partially-Homogeneous Disturbance with Persymmetric Covariance
  This letter deals with the problem of adaptive signal detection in partially-homogeneous and persymmetric Gaussian disturbance within the framework of invariance theory. First, a suitable group of transformations leaving the problem invariant is introduced and the Maximal Invariant Statistic (MIS) is derived. Then, it is shown that the (Two-step) Generalized-Likelihood Ratio test, Rao and Wald tests can be all expressed in terms of the MIS, thus proving that they all ensure a Constant False-Alarm Rate (CFAR). 
D. Ciuonzo and D. Orlando and L. Pallotta
cs.IT math.IT