Jittered chirp sequence waveform in combination with CS‐based unambiguous Doppler processing for automotive frequency‐modulated continuous wave radar

Abstract

The chirp sequence waveform is one of the most commonly used waveforms for automotive frequency‐modulated continuous wave radars. When a chirp sequence waveform is applied, the range–Doppler processing method based on two‐dimensional fast Fourier transform can be used to extract the range and velocity parameters of multiple targets from the beat signals. However, conventional chirp sequence waveforms suffer from the Doppler ambiguity problem, which results in ambiguities in velocity measurement. In this study, the authors propose a novel jittered chirp sequence waveform. In the proposed waveform, the initial times of the chirps are randomly jittered. According to the compressed sensing theory, they establish the parameter design principle for the new waveform, and apply sparse recovery method to achieve unambiguous Doppler processing. Subspace pursuit algorithm is recommended as the suitable sparse recovery method for Doppler processing due to its low complexity and stable recovery performance. The effectiveness of the proposed waveform and its corresponding signal processing method are verified by simulation and experimental results.

Keywords

• jittered chirp sequence waveform
• CS‐based unambiguous Doppler processing
• automotive frequency‐modulated continuous wave radars
• range‐Doppler processing method
• two‐dimensional fast Fourier transform
• range parameter extraction