Correction of migration through resolution cell in bistatic inverse synthetic aperture radar in the presence of time-varying bistatic angle

Abstract

When the size of target or the rotation angle is big, migration through resolution cell may occur in the bistatic inverse synthetic aperture radar (ISAR), which will affect the imaging quality. Aiming at the problem of migration through resolution cell of bistatic ISAR in the presence of time-varying bistatic angle, a correction algorithm is proposed in this paper. Firstly, the echo model of bistatic ISAR is built, and the mechanism of migration through resolution cell is analyzed. Migration through range cell may be corrected through the generalized Keystone transformation, and the effect of non-uniform rotation is eliminated at the same time. Then the rotating center is estimated according to the maximum criterion of image contrast, and the range bin is scaled absolutely. A phase compensation term is constructed and the correction of migration through Doppler cell is finished. Finally, the simulations are carried out and the results show that the method proposed in this paper can solve the problem of migration through resolution cell and improve the image quality.