An imaging system uses wideband "RF daylight" created by plural narrowband RF illumination sources, to passively generate spectrally different sets of RF scattering coefficients for multiple points within a prescribed three-dimensional volume being illuminated by the narrowband RF transmitters. To correct...http://www.google.fr/patents/US6700527?utm_source=gb-gplus-shareBrevet US6700527 - Coherent two-dimensional image formation by passive synthetic aperture collection and processing of multi-frequency radio signals scattered by cultural features of terrestrial region
Coherent two-dimensional image formation by passive synthetic aperture ...
