在ISAR成像中,某些雷达目标的部件存在旋转运动,会对回波信息引入微多普勒,从而导致成像质量下降,严重时甚至无法实现成像。该文提出一种基于对慢时间积分的简易方法,成功实现了微多普勒信息与目标主体信息的分离,获得了较为清晰的目标主体像;通过对微多普勒信息的分析,同时也能获得旋转部件的一些运动信息,如旋转半径、旋转频率等。仿真结果证明了该方法的有效性,并简单验证了不同信噪比条件下其微多普勒谱的提取性能。
The micro-Doppler effect may be generated by additional frequency modulations on the returned radar signal, if the target contains rotating structures, such as a rotor on a helicopter. The body image will be contaminated duo to the existence of the micro-Doppler. In the paper, a simple method based on integral of slow-time is introduced, which has separated the signal from the body of target and that from the rotating parts successfully. It makes the ISAR image clearer, and also provides some information of the rotating parts, such as the radius and the rotation frequency. Finally, a computer simulation is given to prove the effectiveness of the method, and the performances of extraction of micro-Doppler spectrogram in the condition of different SNR are also discussed.