A portable 35 GHZ cross-track interferometer for topographic and surface change measurements

In the following, we present first results obtained from the design, construction and deployment of a 35 GHz fixed-point radar interferometer, that uses the principles of FMCW for generating a range resolving signal. Using a single transmit antenna and two receive, separated by an interferometric baseline, it is possible to determine phase differences between the two receive channels, and given the viewing geometry, to solve for the target topography. To test the system described in this short paper, it was deployed on a local mountain top, some 270m above the local terrain. With knowledge of the nominal topography (measured by the Shuttle Radar Topography Mission; SRTM), and sufficiently large interferometric height ambiguity, it is possible to solve for the topography, as seen at 35 GHz, and to monitor differences in the observed topography which may be due to differences in volume scattering, surface motion, and surface dielectric change.