Implementation method for wide swath earth observation step scanning mode of synthetic aperture radar

The invention discloses an implementation method for a wide swath earth observation step scanning mode of a synthetic aperture radar, and relates to a synthetic aperture radar technique. In each sub-band, an antenna is along a track direction in azimuth direction, performs step scanning from back to front and receives returning waves, and the resolution ratio is changed by controlling the azimuthscanning speed of the antenna; and after the sub-band is scanned, in range direction, the beam position is switched to ensure that the antenna illuminates different sub-bands so as to realize wide swath. By the implementation method, the scallop effect of a normal scanning (ScanSAR) mode is obviously improved, and the azimuth resolution, the fuzzy ratio and the noise equivalent coefficients in a whole scene are uniform. When the scanning capacity of the antenna is strong, by the wide swath earth observation step scanning mode, a resolution ratio which is superior to that of the ScanSAR mode can be acquired.