Advanced terrain tracking altimeter

The advanced terrain tracking altimeter (ATTA) has been proposed for the next generation of polar orbiting platforms of the European Space Agency. The results of a feasibility study into the design of such an instrument are reported. Adaptive processing is used to allow the instrument to maintain maximum resolution over the ocean while adopting coarser resolution over topographic surfaces. The possible data products and applications are summarized together with the operation of the tracking algorithms required. An experimental synthetic aperture mode of operation is assessed. The instrument has a built-in radiometer to estimate the wet tropospheric delay correction and a dual-frequency altimeter to provide for ionospheric delay corrections.