Pulse-agile waveform design for nonlinear FM pulses based on spectrum modulation

The transmission of pulses with different intra-pulse modulations within a coherent processing interval (CPI), also known as pulse-agile radar, has several potential applications. For the detection of small targets with long range and slow velocity in the background of strong clutter, the conventional pulse-Doppler (PD) radar is limited by range ambiguity and folded clutter. It is feasible to solve this problem through the agility between pulses. In this paper, a non-repeating, spectrum modulated nonlinear frequency modulation (NLFM) waveform applicable for pulse agility radar is described. Based on the spectrum structure of linear frequency modulation (LFM) signal, the waveform modulates its power spectral density by a random sinusoid to achieve good cross-correlation properties, which can suppress the range ambiguity and folded clutter. Simulation results are provided to demonstrate the effectiveness of the proposed approach.