Inverse methods applied to microwave target imaging

Descriptions are given of many different methods currently in use at a radar modelling facility where target images derived from microwave data are being investigated. These studies exploit measurements made at wavelengths between 0.3 m and 0.3 mm on both full-scale targets and suitably scaled models. Results of Doppler processing are used to illustrate the equivalence of modelling and full-scale data. Both DFT methods and maximum entropy processing are applied to coherent-radar data measured in an arc-scan around the target. Stacked spectra, in particular those produced by the latter method, are very revealing. Examples are given of the processing of polarization scattering matrix data. Images obtained at millimeter wavelengths both by radiometry and by holographic methods are illustrated. The relative merits of the various imaging processes are discussed.