Generation of High Resolution Radar Range Profiles and Range Profile Auto-Correlation Functions Using Stepped-Frequency Pulse Train

Abstract

This report describes some of the issues involved in using stepped-frequency radar pulse trains to obtain high resolution target range profiles. Radar returns from stepped-frequency pulse trains may be processed either coherently or noncoherently. Coherent processing consists of taking the Fourier transform of the N coherently-detected (complex) pulse returns from each range cell, where N is the number of pulses in the train. The output of the transform is the high resolution range profile of the scatterers within that range cell (i.e., within the span of a single pulse width). Noncoherent processing consists of taking the Fourier transform of the squared-magnitudes of the pulse returns from a given range cell and yields the auto-correlation function of this range profile. In either case, the resulting range resolution (of both the profile and its auto-correlation function) is determined by the total bandwidth (i.e., the frequency spread) of the pulse train. The stability requirements of the variable frequency source used to generate the stepped frequencies of the pulse train are determined for both the coherent and noncoherent processing cases.