Phase Estimation and Correction of Nonlinear Sweep Frequency for Detecting Vehicle Targets with FMCW Radar

The voltage controlled oscillator (VCO) of the frequency modulation continuous wave (FMCW)radar is usually non-linear, which causes the radar range resolution to decrease. The non-linearity of frequency sweep is one of the main problems that limit the range resolution of chirp continuous wave radar. Although the traditional method based on polynomial model can correct most of the nonlinear distortion in the system, it is difficult to suppress the paired echoes caused by periodic nonlinearity, and there is still a large space for improving the quality of range compression. We propose a novel method to measure the systematic phase errors which are required as input to the compensation algorithm. Simulation results show that the proposed algorithm can effectively eliminate the periodic phase error and significantly improve the quality of range compression.