METHOD FOR PRODUCING AN EARTH OBSERVATION IMAGE OF A REGION BY MEANS OF A RADAR HAVING SYNTHETIC APERTURE

摘要

The invention relates to a method, in which an earth observation image of a region is produced by means of a radar having synthetic aperture (SAR) and a phase-controlled array antenna, which is composed of individual antennas and has an azimuthal pivot angle range that can be achieved by a control angle. Each individual antenna has an element factor describing the individual antenna gain as a function of the spatial angle, and the array antenna has an array factor which describes the array antenna gain resulting from the arrangement and number of individual antennas as a function of the spatial angle, wherein the array antenna gain has a plurality of main maxima which are substantially equal, but which are, with regard to the total gain resulting from the element factor and the array antenna gain, are attenuated towards increasing control angles. The usable azimuthal pivot angle range is widened in the detection of a region by repeatedly adjusting the same control angle within the unique control angle range defined by the geometric arrangement of the individual antennas, and by filtering out the one ambiguous main maximum which points in the respectively desired control direction, whereby the geometric and/or radiometric resolution of the SAR is improved. The pulse repetition frequency, with which the radar pulses are sent, is selected such that the respectively desired and undesired main maxima are separated for reducing the undesired main maxima, and thus a filtering out of said main maxima is ensured.