Interferometric synthetic aperture radar for terrain mapping

The paper describes a new technique for topographic mapping using an interferometric synthetic aperture radar (IFSAR). The IFSAR utilizes microwave interference for precise measurement of small linear displacements related to the surface topography. It is similar to a traditional SAR system except that it has two receive antennas (with essentially the same boresight) and the single recording channel is replaced by two independent channels one for each antenna. From each imaging pass, the IFSAR measures (in addition to the backscattered power) the relative range distance from each antenna to the target pixel. The direct measurement is a relative phase difference which is related to the range diversity between the two antennas and the target area by the wavenumber. Using the relative phase difference in conjunction with the ranging and Doppler information, one can solve directly for the 3-D target location to produce an 3-D map of the target area without any Earth model assumption