基于24 GHz FMCW 雷达的二维近场成像系统

2D Near-Field Imaging System for 24 GHz Frequency ModulatedContinuous Wave Radar

中文关键词:  近场雷达成像,调频连续波雷达,合成孔径雷达,快速傅里叶变换

英文关键词:near-field radar imaging, frequency modulated continuous wave (FMCW) radar, synthetic aperture radar (SAR), fast Fourier transform

中文摘要:

      为进行隐藏危险金属制品的安检,文中提出了一种24 GHz 低成本毫米波成像系统。该系统采用低成 本24 GHz 商用调频连续波(FMCW)雷达作为扫描源,在方位角和仰角上合成大孔径,使用二维十字扫描平台,经 FMCW 雷达信号处理以及合成孔径雷达(SAR)处理使隐藏物体成像。低成本的射频外设只提供了一路中频实信号 供ADC 采样量化,在图像重建中,文中提出将单路ADC 采样量化后的中频数字信号通过希尔伯特变换成复信号,对 复信号加布莱克曼窗优化频谱,再对信号序列补零以减小频域栅栏效应,后采用空间匹配滤波器补偿相位偏差,通 过FMCW 雷达近场成像原理对目标成像。改进后的算法适用于低成本的雷达前端系统,只需一路ADC 采集的中频 数字信号即可使成像系统达到理论的合成孔径成像分辨率。

英文摘要:

      A 24 GHz low-cost millimeter wave imaging system is proposed for security inspection of hidden dangerous metal products. The system uses a low-cost 24 GHz commercial frequency-modulated continuous wave (FMCW) radar as the scanning source, synthesizes large aperture at azimuth and elevation angles, and uses a 2D cross scanning platform to image hidden objects through FMCW radar signal processing and synthetic aperture radar (SAR) processing. Low cost RF peripheral only provides single-channel IF signal by the ADC sampling quantization, all the way in the image reconstruction, this paper puts forward the single-channel ADC sampling after quantification of IF digital signal through the Hilbert transform into a complex signal, optimization for complex signal and Blackman window spectrum, then the signal sequence zero padding to minimize frequency fence effect, after adopting spatial matched filter to compensate the phase deviation, the near field imaging principle of FMCW radar is used to image the target. The improved algorithm is suitable for the low-cost radar front-end system, and the imaging system can achieve the theoretical SAR imaging resolution only by collecting only one channel IF digital signal from the ADC.