Implementation of an adaptive space-time processor by an unconstrained multichannel lattice

The structure for the adaptive multichannel space-time processor which implements a likelihood ratio processor for detection of multiple slowly fluctuating scatterers in a nonstationary, anisotropic, Gaussian interference is derived. The adaptive part of the processor can be realized by multi-input, multi-output unconstrained lattice filters. This structure has the advantage that the adaptive part of the processor is determined by the spatial and temporal properties of the noise field and it is common to all of the beam-steering directions. The adaptive processor is followed by a beamsteering operator, consisting of a matrix of delay operators, which simultaneously forms a set of beams in all the desired look directions. This structure is computationally more efficient than structures based on the constrained adaptive algorithms.