基于差分滤波的非线性估计及校正方法

在线性调频连续波雷达系统中，各个器件的非理想特性使得信号的相位产生各种畸变，严重影响雷达的测距精度以及成像质量，需要经过一定的校正手段才能获得高精度的测量结果。该文针对线性调频连续波信号以及确定性非线性相位的特点，建立了受到非线性干扰的线性调频连续波信号模型，提出一种新的基于差分滤波的非线性估计方法能够对周期性及非周期性非线性进行同时估计，并利用匹配傅里叶变换(MFT)方法对非线性相位进行校正。通过仿真和对比分析，表明该方法与其他方法相比具有更高的估计精度，且在非线性度较大时也能够具有良好的校正效果。最后采用雷达的实测数据验证了该算法的有效性。

A Method of Nonlinearity Estimation and Correction Based on Difference Filtering

In the linear Frequency Modulation Continuous Waveform (FMCW) Radar system, due to the non-ideal characteristics of each instrument, the phase of the signal produces various distortions, which affects seriously the radar's ranging accuracy and imaging quality. It requires certain correction methods to obtain high-precision measurement results. In view of the characteristics of FMCW signal and deterministic nonlinear phase, this paper establishes a FMCW signal model subject to nonlinear interference, and proposes a new nonlinear estimation method based on difference filtering, which can simultaneously estimate periodic and non-periodic nonlinearities, and uses Matching Fourier Transform (MFT) method to correct the nonlinear phase. Simulation and comparative analysis show that this method has higher estimation accuracy than other methods, and it can also have a good correction effect when the nonlinearity is large. Finally, the actual measurement data of the radar is used to verify the effectiveness of the algorithm.