0.14THz高分辨力成像雷达信号处理

Signal processing for 0.14 THz high resolution imaging radar

为适应0.14THz超高分辨雷达实时成像的需求,开发了基于CPU+GPU+FPGA的硬件架构和成像处理算法,算法以距离-多普勒为原型,引入L类维格纳分布变换提高横向分辨力,用Keystone变换方法对越距离单元徙动进行校正,并开发了系统非线性补偿算法。在载频0.14THz、带宽5GHz雷达样机上进行了逆合成孔径雷达成像试验,获得了3cm×3cm的成像分辨力和实时成像能力,验证了信号处理方法的有效性。

A real-time signal processing system was designed for the 0.14 THz high resolution imaging radar. The hardware structure was established using CPU＋GPU＋FPGA to enhance its operation ability. In this inverse synthetic aperture radar （ISAR）, the range-Doppler algorithm is used to get higher imaging speed, and L-class Wigner-Ville distribution （LWVD） is adopted to improve the cross-range resolution. An algorithm called Keystone transformation is used to dispose the time domain signal by de-chirp processing, and it eliminates the migration through resolution cell （MTRC） in the target imaging. A method of chirp nonlinearity compensation for the imaging system was also proposed. This signal processing module was applied to a terahertz radar system with 0.14 THz carrier frequency and 5 GHz bandwidth. ISAR images were obtained by using this THz radar system with 3 cm resolution in both range and cross-range profiles, showing the validity of the signal processing method.