Wideband Radar Imaging for Space Debris based on Direct IF Sampling Signals

摘要

This paper investigates an imaging method for space debris by wideband radar. Because of the spinning of the space debris, the correlation of the adjacent high range resolution profile (HRRP) is undermined and the motion compensation method for dechirped echoes is invalid. Therefore, a wideband imaging method of space debris based on intermediate frequency sampling (DIFS) signals is proposed in this paper. The IF sampling technique has the advantage in maintaining the coherence of echo pulse, which eliminates the negative influence of the spin. Firstly, the accurate translational motion parameters of the target are estimated from the radar observations by using of polynomial fitting method. Then the translational motion compensation is carried out in frequency domain based on the target motion track. Finally, the improved back projection transform (BPT) method is used for image reconstruction, which transforms the echo from range-time domain to the scattering point distribution plane by coherent integral. A well-focused and high resolution image of the space debris without side lobe peaks can be obtained in the end. The simulation results indicate the validity of the proposed method in this paper.