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强地杂波背景给微动目标检测带来很大困难,为此在详细分析距离向压缩数据域自旋目标回波特性基础上,提出了基于双通道合成孔径雷达相位中心偏置天线(SAR/DPCA)和沿航迹干涉(ATI)杂波抑制的两类自旋目标检测方法,并作比较分析。在DPCA模式下,微多普勒频率沿频率(m-D)轴有一整体平移量,其与目标自旋中心的方位向坐标成正比,由此可在估计目标微动参数的同时对其定位;在ATI模式下,不能直接由干涉信号虚部作时频变换来获取微多普勒特征,为此提出了一种基于干涉信号虚部重建自旋目标复信号的微多普勒提取方法。从避免微多普勒模糊的角度,指出在较小基线长度的情况下,ATI模式较DPCA模式对雷达脉冲重复频率(PRF)的要求更宽松,更适宜于大旋翼类目标检测。不同模式下的仿真数据验证了理论分析和所述方法的正确性。
The background of strong clutter brings great difficulties to the detection of fretting targets. Based on the detailed analysis of the echo characteristics of the spin target in the compressed data from the distance to the target, a method based on the dual-channel SAR antenna is proposed SAR / DPCA) and track-based interference (ATI) clutter suppression, and compared them. In DPCA mode, the micro-Doppler frequency has a global translation along the frequency (mD) axis that is proportional to the azimuthal coordinates of the target’s spin center, allowing it to be located while estimating the target fretting parameters; at In the ATI mode, the Doppler characteristics can not be obtained directly by the time-frequency transform of the imaginary part of the interfering signal. Therefore, a micro-Doppler extraction method based on the imaginary part reconstruction of the spins is proposed. From the perspective of avoiding the micro-Doppler ambiguity, it is pointed out that the ATI mode is more relaxed than the DPCA mode for the radar pulse repetition frequency (PRF) at a small baseline length, and is more suitable for large rotor target detection. The simulation data under different modes verify the theoretical analysis and the correctness of the method.