基于相干探测的动目标多普勒频谱识别

Doppler Frequency Spectral Discrimination of Moving Target Based on Coherent Detection

激光相干探测由于其高灵敏及抗干扰特性，在现代精密检测中应用逐渐广泛。由于目标二维信息更能反映目标特性，利用PCI8522采集忙与振镜扫描控制信号进行模拟量触发源（ATR）触发同步，快速获取目标二维多普勒频谱。对室内裸露以及伪装网覆盖的旋转漫反射目标进行二维频谱提取，二维频谱图为31pixel×31pixel，目标存在区的频谱范围在3～7MHz之间，通过二维频谱图能对典型目标轮廓进行识别。对图像恢复算法中引入的噪声进行分析．结果表明：其中目标覆盖区中轴线附近噪声概率较大，主要由200kHz的频谱门宽引起；另一类噪声为背景无多普勒频移的5MHz中心信号被频谱门宽限制所致，可作为目标轮廓衬底，无需抑制。该研究为激光相干探测在动目标伪装识别中的应用奠定基础。

Laser coherent detection has applied widely in the area of modern precise detection due to its high sensitivity and anti-disturbance property. The two-dimensional （2D） image information has more ability to reflect the property of the target. Therefore, the PCI8522 data asquisition （DAQ） card and the scanning galvanometer are combined together through analog trigger （ATR） trigger synchronizing for the purpose of receiving the Doppler frequency spectrum. The 2D frequency spectra are obtained for naked and camouflage net covered rotating diffuser, and the imaging size is 31 pixel X 31 pixel. The Doppler frequency ranges from 3 MHz to 7MHz, and the target from the noisy background through the 2D frequency spectral image can be distinguished. The noise in the image processing is analyzed and the results are as follows= the area near the center axis of the target has large noise probability and the main reason is the frequency spectral gate with 200 kHz span. The other kind of noise comes form 5 MHz center frequency without Doppler frequency shift restricted by the frequency spectral gate, and there＇s no need to wipe off this kind of noises because it is the background of the useful information. This research can be the basis of the application of laser coherent detection in the field of moving target camouflage discrimination.