Research On Compressive Sensing In ISAR Imaging

Inverse synthetic aperture radar(ISAR)is widely employed in military and civil fields,and its imaging technology is a hot research topic.ISAR targets are usually non-cooperative,and there is no guarantee of time for these targets to be observed.The received target echo is usually discontinuous.In this case,the traditional range-Doppler imaging method cannot get a clear ISAR image.An emerging theory of compressive sensing is introduced in this paper.The emerging theory can be used for signal reconstruction under a sampling rate lower than the Nyquist sampling rate to successfully solves ISAR imaging problem in the absence of data.The observation matrices in the compression sensing algorithm have complex construction problems in engineering practice.In this paper,the observation matrix based on Logistic chaotic sequence is designed and the engineering realization is simpler when the reconstruction precision is guaranteed.Many targets generate Doppler frequencies relative to radar motion,and other mechanisms on the target produce micro-Doppler effects.The micro-Doppler effect decreases the ISAR imaging quality,so it needs to be eliminated.While eliminating the micro-Doppler Effect will cause data loss.So an elimination of micro-Doppler effect of ISAR imaging algorithm which is combined with compression sensing is proposed in this paper.The algorithm can effectively reconstruct the ISAR target image when eliminating the micro-Doppler effect.ISAR imaging of target scene discretization may produce off-grid problem.This problem is more serious when using compressive sensing algorithm but this aspect research is less.In this paper,an adaptive refinement grid algorithm based on compressive sensing is proposed to solve the off-grid problem.Firstly the imaging principle of ISAR which includes the ideal model of turntable and motion compensation theory is introduced in this article,and the ISAR measured data is used to image.Secondly,the compressive sensing principle and the three main components are introduced in detail.Then the principle of compression sensing algorithm based on Logistic chaotic sequence is introduced.The effectiveness of the algorithm is verified by sinusoidal signal,MIG-25 simulation data and ISAR measured data.Then the ISAR micro-Doppler elimination algorithm based on compressive sensing is introduced,and its validity is verified by an ISAR data.Finally the off-grid phenomenon in ISAR imaging is introduced,and an adaptive refinement grid algorithm based on compression perception is introduced,the effectiveness of the proposed algorithm is verified by sinusoidal signal too.