Field tests of the GeoSTAR demonstrator instrument

Ground based tests of the GeoSTAR (Geostationary Synthetic Thinned Array Radiometer) demonstrator instrument are reported which simulate the view of the Earth from geosynchronous Earth orbit (GEO). The test used a 4-meter target disk mounted on a tower above the instrument to simulate the brightness of the Earth with a contrasting cold background. Continuous observations at 50.3 GHz for over 100 hours, along with simultaneous atmospheric measurements from independent radiometers, yielded an excellent data set with which to test all aspects of the GeoSTAR calibration. This paper presents a preliminary look at these data, and presents an algorithm to remove the aliased background from the synthesized image.