Abstract: The clutter distribution of an airborne radar with uniform circular array antennas varies with its range, and samples in different range gates are not identically distributed independent vectors, so that the statistical space-time adaptive processing (STAP) methods deteriorate. In this article, based on the proposed twodim clutter model and a detailed analysis of clutter distribution for airborne radars with uniform circular array antennas, the conclusion is drawn that the non-linear relation between space angle and number of arrays results in the nonhomogeneity at range for an airborne radar with circular array antennas. A clutter suppression method is discussed in this article which involves first preprocessing with the modified angle-Doppler compensation (MADC) method to align the centers of a clutter spectrum in different range gates and subsequently performing clutter suppression in other azimuths with derivative based updating (DBU) technology. Simulation results show the validity of this method.

Key words: uniform circular array, radar, clutter suppression, angle-Doppler compensation, space-time adaptive processing