Determination of a Microwave Radiometer Antenna Pointing Using Infrared Coincident Data

Abstract

The ERS-1 microwave radiometer is dedicated to the correction of the wet tropospheric path delay of the altimeter signal. The accurate location of the microwave footprints is needed because (i) the derived correction must be obtained on the same air column as the altimeter, and (ii) the correction algorithm requires coincident microwave footprints. The authors benefited from the infrared radiometer on board the same platform to test a method for accurately determining the microwave antenna pointing. Preliminary results of this method are presented: although the microwave footprints are more than 20 km wide, their locations are obtained with an accuracy better than 3 km. These locations lie within the preflight tolerances. The microwave-based retrieval algorithms can therefore be used with confidence. This method could be applied to other platforms where both infrared-visible and microwave data are available.