Tomographic Imaging for Orbital Radar Sounding of Earth's Ice Sheets

BingSat-Tomographic Observation of Polar Ice Sheets (BingSat-TOPIS) is a spaceborne multistatic radar sounding system that can achieve high resolution and stereoscopic observation. It is designed to penetrate ice sheets and acquire tomographic image. The satellite group fly over the Polar Regions, which can form about 6.56-km cross-track baseline. This cross-track baseline is formed by one master satellite and 40 slave CubeSats. In this article, we propose a tomographic imaging algorithm for orbital radar sounding of the Earth's ice sheets. First, we give the method to calculate the two-way slant range in air and ice. The phase errors of the method are smaller than π/4 rad. Second, we express the radar data cube for a point target in ice sheets. The radar data cube is made of 40 bistatic synthetic aperture radar echo signals. At last, the echoes are simulated for the TOPIS system, and a matched filter is used for pulse compression in range. Then, the back projection algorithm is used in track and cross-track imaging. The experimental results demonstrate that our tomographic imaging algorithm is effective and reliable.