COHERENT TWO-DIMENSIONAL IMAGE FORMATION BY PASSIVE SYNTHETIC APERTURE COLLECTION AND PROCESSING OF MULTI-FREQUENCY RADIO SIGNALS SCATTERED BY CULTURAL FEATURES OF TERRESTRIAL REGION

摘要

An imaging system uses wideband RF daylight created by plural narrowband RFillumination sources, to passively generate spectrally different sets of RFscattering coefficients for multiple points within a prescribed three-dimensional volume being illuminated by the narrowband RF transmitters. Tocorrect fot the lack of mutual coherence among different RF illuminationsources, the respective sets of scattering coefficient data are applied to acultral feature extraction operator, to locate one or more strong culturalfeatures spatially common to multiple images. For spatial points along theextracted cultural feature theoretical scattering coefficients are calculated.Differences between phase values of these calculated scattering coefficientsand those of the collected and processed scattering energy are used to modifythe measured scattering coefficient values for all points in the illuminatedregion.