Case study of principal component inverse and cross spectral metric for low rank interference adaptation

This paper presents a review of the principal component inverse (PCI) method of rapid adaptive signal detection and contrasts the use of principal components with the cross spectral metric (CSM) method for the generalized sidelobe canceller. The CSM method is optimal with known statistics and has been shown to outperform the PCI method in many cases of unknown covariance. This paper describes a scenario which represents a class of covariances where the PCI method can be expected to outperform the CSM method. The choice of method is therefore more subtle than previously thought