Microwave imaging of time-varying radar targets

The study deals with the introduction of coherent imaging ideas in the kinetic analysis of systems. It is developed in the radar context and is devoted to the description of general targets exhibiting motion, scintillation and dispersivity. This description is based on a physical model of small independent reflectors which can be moving and non-permanent. The resulting representations are generalized images which correspond to densities in a position– velocity–time–frequency space. A theoretical approach of the subject is presented in which the imaging problem is expressed as a phase-space representation problem associated with the Weyl– Poincaré group. The physical relevance of the formulation is emphasized and two procedures are proposed to make it practical. The first one is founded on a special wavelet analysis of the target backscattering function and the second one on the introduction of a generalized Wigner function. Connections with previous works on the same subject are discussed.