INITIAL RESULTS IN THE DEVELOPMENT OF A SYNTHETIC APERTURE MICROWAVE RADIOMETER

The Goddard Space Flight Center and the University of Massachusetts have been developing a synthetic aperture radiometer for microwave remote sensing of the earth. The radiometer measures the complex correlation of the voltage from pairs of antennas at many different baselines. Each baseline produces a sample point in the Fourier transform of the scene, and a map of the scene itself is obtained after all measurements have been made by inverting the transform. A substantial reduction can be obtained in this manner in the antenna collecting area required compared to a conventional imaging radiometer. An aircraft prototype to demonstrate this concept is being developed at L-band to measure soil moisture. The prototype is a hybrid which uses real aperture antennas to obtain resolution along-track (stick antennas) and employs aperture synthesis to obtain resolution acrosstrack. The prototype was flight-tested aboard the NASA P-3 in June 1988. During this flight a map was made of the Delmarva Peninsula south of NASA’s Wallops Flight Facility. This initial map shows the major land/water features and compares very favorably with a Landsat image of the area, suggesting a bright outlook for the development of this technique in the future. © 1990 IEEE