Non-Coherent Discrete Chirp Fourier Transform for Modulated LFM Parameter Estimation

Linear frequency modulated (LFM) waveforms play a significant role in both military and civilian detection and ranging applications. Based on LFM, researchers have designed a phase shift keying (PSK) modulated LFM waveform to enable both communication and radar functions simultaneously. Estimating the chirp rate and carrier frequency of data modulated LFM waveforms is therefore of interest in defence applications. In the previous research, the discrete chirp-Fourier transform (DCFT) was proposed to estimate the parameters for non-modulated waveforms. However, the DCFT method is limited with respect to the transform length and the estimation range. Thus, this paper proposes a generalised coherent DCFT that extends the previous DCFT method. We also introduce a novel non-coherent DCFT to improve parameter estimation for PSK modulated LFM waveforms. In the simulation section, this paper discusses the applicability of two modified DCFT methods and demonstrates their superior performance.