摘要
基于传统R-D算法(Range Doppler Algorithm)的ISAR成像是基于目标平稳运动的假设,而对机动目标,由于R-D算法将相同散射点不同时刻表现的不同频率压在一起,从而使散射点展宽、图像模糊不清。文中首先分析经典傅里叶变换与时频分析的本质区别;然后阐述几种典型的时频分布的交叉项干扰情况、时频聚集性能,与其他时频分布相比,重排Gabor时频分布性能优良,不仅时频聚集性好,而且无交叉项干扰,对目标瞬时成像效果较好;最后,仿真和实测数据验证了成像算法的有效性。
The traditional range Doppler algorithm is suitable only to the stationary target. When the target moves irregularly, the Doppler frequency of each scatterer and the imaging projection plane of a maneuvering target may change with time, which makes scattering points wider and ISAR image blurry. This paper compares Fourier transform with time-frequency analysis. Then, it analyzes time-frequency concentration and cross-term interference of several typical time-frequency distributions. We find that reassigned Gabor spectrum time-frequency distribution is better for time-frequency concentration and cross-term suppression, and can obtain good instantaneous images of targets. Finally, the simulated data and real data demonstrate the validity of the method proposed.
出处
《现代雷达》
CSCD
北大核心
2009年第7期46-49,共4页
Modern Radar
关键词
R—D算法
傅里叶变换
时频分析
重排Gabor谱
ISAR成像
R-D algorithm
Fourier transform
time-frequency analysis
reassigned Gabor spectrum time-frequency distribution
ISAR imaging
