基于时频二维图像的高频雷达低速目标检测

Low velocity target detection based on time-frequency image for HFGW radar

海面低速目标的非均匀运动和射频瞬态干扰引起的多普勒谱展宽影响高频地波雷达检测目标的准确性。利用时频分析方法将相干积累时间内由于目标非均匀运动和射频干扰引起的信号能量变化显示于时间-频率二维图像上,并根据目标信号对应时频图像上非线性曲线的特点提出一种基于二值形态学的方法用于区分目标和干扰信号。现场数据的分析结果证明该方法可以从展宽的多普勒谱中准确地检测出目标。

The Doppler spectral broadening due to nonstationary movement of target and radio-frequency clutter will decrease the veracity of target detection by high frequency ground wave（ HFGW） radar. By displaying the change of signal energy on a two dimensional time-frequency images based on time-frequency analysis, a new mathematical morphology method to distinguish target from the nonlinear time-frequency curve is presented. The analyzed results from the measured data confirm that with this new method, the target can be detected correctly from wide Doppler spectrum.