Parameterized self-focusing method for compensating impact on GEOSAR imaging from background ionized layer

The invention discloses a parameterized self-focusing method for compensating the impact on GEOSAR imaging from a background ionized layer, and the method comprises the steps: firstly carrying out the range pulse compression of raw echo data of GEOSAR through matched filtering; selecting a rectangular region in a GEOSAR imaging region, and carrying out grid division; secondly carrying out envelope alignment and phase compensation of the GEOSAR data after range pulse compression, and calculating the coefficient of the background ionized layer relative to a high-order change function along with orientation slow time through a law of image minimum entropy; finally judging whether the iteration is ended or not; carrying out the enveloping and phase compensation of all imaging regions through the high-order change function obtained through iteration if the iteration is ended, thereby achieving the GEOSAR imaging in the region. The method achieves echo envelop walk correction and phase error compensation, which are caused by the high-order change of the background ionized layer, in a mode of iteration through employing the characteristic that the variation tendency of the background ionized layer in a GEOSAR synthetic aperture time can be approximated to be a polynomial based on the law of image minimum entropy, thereby effectively improving the GEOSAR imaging quality.