Owing to the enormous amount of frozen water and the particularity of heat exchange, polar ice sheets act as an important indicator and amplifier of global climate change. However, the detection and cognition of the tomographic structure of polar ice sheets remain insufficient due to the special geographical location and harsh weather. Benefit from the advantage of strong penetrability and high-precision range measurement, the ice sounding radar is an optimal instrument for tomographic detection of polar ice sheets, which significantly promotes the development of polar science. Nevertheless, existing radar satellites still cannot detect ice beds in depth because of the complex low-frequency signal propagation in ice and an extremely long operating distance. This study focuses on the scientific objectives (spatial resolution: 100 m and revisit time: 3 months) and presents an in-depth analysis of the key problems of orbital ice sounding radar, including transmission attenuation, firn clutter, and cross-track resolution deterioration. With reference to the current state and trend of radar satellite technology, we proved the feasibility of the application of distributed Synthetic Aperture Radar (SAR) on the microsatellite platform for ice bed detection, identified the key parameters of distributed SAR and the technical challenges of orbital radar sounding system for polar ice sheet tomographic observation, and further explored the implementation scheme.
