Systems Engineering and Electronics ›› 2018, Vol. 40 ›› Issue (3): 538-545.doi: 10.3969/j.issn.1001-506X.2018.03.08

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Nonlinearity phase estimation and correction of FMCW radar

LI Gongquan, LAI Tao, JIN Ke, ZHAO Yongjun   

  1. School of Navigation and Aerospace Engineering, PLA Information Engineering University, Zhengzhou 450001, China
  • Online:2018-02-26 Published:2018-02-24

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Abstract:

In order to obtain a high-quality range image, frequency modulated continuous wave (FMCW) radar usually requires modulation nonlinearity correction under the mechanism of dechirp reception. Traditional methods based on the polynomial phase model can correct most nonlinear distortion in the system, but it is hard to eliminate the paired echoes invited by period nonlinearity, which reveals great improvement still exists in range compression. The residual nonlinearity error is modeled as a multi-component sinusoidal FM signal, and after that, a parameter estimation method combining initial value matching and nonlinear least squares optimization is proposed. The method can achieve high efficiency in the estimation of sinusoidal frequency modulation parameters via Fourier transform and one-dimensional phase searching. Then, the nonlinear least squares is used to further improve the estimation accuracy. Finally the range-dependent nonlinearity is corrected by match Fourier transform. Simulation and radar echo processing results demonstrate that the proposed method can effectively eliminate periodic phase nonlinearity, suppress paired echoes, and significantly improve range compression quality.

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