Scaled Conjugate Gradient Method for Radar Pulse Modulation Estimation

This paper addresses the problem of estimating a common modulation from a group of intercepted radar pulses. Estimated modulation profile operates as the basis for specific emitter identification (SEI). A robust M-estimation technique using scaled conjugate gradient algorithm for improving the frequency alignment of the pulses is proposed. In addition, postprocessing of the estimated modulation profiles for identification is considered. Simulation experiments are conducted in order to compare the performance with previously proposed methods. Results show that the proposed robust M-estimation technique provides improved performance at low signal-to-noise ratio regime due to better frequency alignment of the intercepted pulses.