Quadratic Frequency Modulation Signals Parameter Estimation Based on Two-Dimensional Product Modified Parameterized Chirp Rate-Quadratic Chirp Rate Distribution

Zhiyu Qu; Fuxin Qu; Changbo Hou; Fulong Jing

doi:10.3390/s18051624

Quadratic Frequency Modulation Signals Parameter Estimation Based on Two-Dimensional Product Modified Parameterized Chirp Rate-Quadratic Chirp Rate Distribution

Sensors (Basel). 2018 May 19;18(5):1624. doi: 10.3390/s18051624.

Authors

Zhiyu Qu¹, Fuxin Qu², Changbo Hou³, Fulong Jing⁴

Affiliations

¹ College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China. quzhiyu@hrbeu.edu.cn.
² College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China. fuxin@hrbeu.edu.cn.
³ College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China. houchangbo@hrbeu.edu.cn.
⁴ College of Information and Communication Engineering, Harbin Engineering University, Harbin 150001, China. jingfl@hrbeu.edu.cn.

Abstract

In an inverse synthetic aperture radar (ISAR) imaging system for targets with complex motion, the azimuth echo signals of the target are always modeled as multicomponent quadratic frequency modulation (QFM) signals. The chirp rate (CR) and quadratic chirp rate (QCR) estimation of QFM signals is very important to solve the ISAR image defocus problem. For multicomponent QFM (multi-QFM) signals, the conventional QR and QCR estimation algorithms suffer from the cross-term and poor anti-noise ability. This paper proposes a novel estimation algorithm called a two-dimensional product modified parameterized chirp rate-quadratic chirp rate distribution (2D-PMPCRD) for QFM signals parameter estimation. The 2D-PMPCRD employs a multi-scale parametric symmetric self-correlation function and modified nonuniform fast Fourier transform-Fast Fourier transform to transform the signals into the chirp rate-quadratic chirp rate (CR-QCR) domains. It can greatly suppress the cross-terms while strengthening the auto-terms by multiplying different CR-QCR domains with different scale factors. Compared with high order ambiguity function-integrated cubic phase function and modified Lv's distribution, the simulation results verify that the 2D-PMPCRD acquires higher anti-noise performance and obtains better cross-terms suppression performance for multi-QFM signals with reasonable computation cost.

Keywords: fast-Fourier transform (FFT); nonuniform fast-Fourier transform (NUFFT); parametric symmetric self-correlation function (PSSAF); quadratic frequency modulation (QFM) signal.