A novel helicopter-borne terahertz SAR imaging algorithm based on Keystone transform

The instability of helicopter flight brings motion errors in the conventional synthetic aperture radar (SAR) imaging. Combined with terahertz (THz) technology, the influence of range migration and low frequency motion error can be significantly reduced. However, it leads the system to be extremely sensitive to platform vibration, which causes paired echoes and deteriorates image quality. A method on platform vibration compensation is proposed in this paper. On the basis of the analytic formula derivation in 2-D frequency domain for the signal, Keystone transform is employed to perform range migration correction. Then platform vibration is compensated in range-Doppler domain. Finally, deghosted images are obtained. The simulation results validate the effectiveness.