基于调频傅里叶变换的改进型鉴相测速

An Improved Phase-Derived Velocity Measurement Method Based on Chirp-Fourier Transform

随着机动目标的高速化、小型化发展,对于雷达的测量精度也提出了更高的要求。鉴相测速能够达到波长级的测量精度,其技术难点主要包括相位提取和解相位模糊。为了降低鉴相测速对信噪比的要求,本文提出了一种基于调频傅里叶变换的改进型鉴相测速方法。首先建立变脉冲重复周期的回波模型,对回波信号进行互相关FFT处理,提取峰值点得到模糊相位;其次对互相关FFT结果进行调频傅里叶变换,得到速度和加速度的粗估计值;然后根据单帧解相位模糊法,对模糊数修正值进行遍历,找出最优解,得到优化后的解模糊相位;最后采用鉴相测速,得到速度的精确值。仿真实验证明了该方法的可行性和有效性。

With the development of maneuvering targets toward high speed and miniaturization, higher requirements are put forward for the measurement accuracy of radar. Phase-derived velocity measurement can achieve wavelength level measurement accuracy, but there are two difficulties in extracting the echo phase and resolving the phase ambiguity. In order to reduce the requirement of signal-to-noise ratio for phase-derived velocity measurement, an improved phase-derived velocity measurement method based on chirp-Fourier transform is proposed. Firstly, an echo model with variable pulse repetition period is established and the echo signal is processed by cross-correlation FFT. The fuzzy phase is obtained by extracting the peak point. Secondly, the chirp-Fourier transform of cross-correlation FFT results is carried out to obtain the rough estimates of velocity and acceleration. According to the single-frame phase solution fuzzy method, the modified value of the fuzzy number is tra-versed to find the optimal solution, and the optimized phase is obtained. Finally, the accurate velocity is obtained by using phase-derived velocity measurement. The feasibility and effectiveness of the proposed method are proved by simulation experiments.