Resolution of center frequency for LFM signals in fractional Fourier domain

Resolution of center frequency for linear frequency modulation (LFM) signals is related with many factors. In fractional Fourier domain, we investigated the relationship between center frequency resolution of two LFM signals and initial phase difference. By establishing center frequency resolution model of two LFM signals with the same amplitude, the same duration and the same chirp rate, we derive the center frequency resolution whenever how much the initial phase difference between two LFM signals is. The maximum value of the center frequency resolution is 1.36/T when initial phase difference varies from 0 to 2π, where T is the signal duration.