Near-space SAR: A revolutionary microwave remote sensing mission

Inspired by the recent advances in near-space defined as the region between 20km and 100km, this paper proposed the concept of near-space SAR. To the author's knowledge, this is the first time that the near-space SAR is being proposed for microwave remote sensing missions. By placing the SAR's transmitter/receiver in the near-space platforms, many functions that are currently performed with the satellites or airplanes could be performed much more cheaply and with much greater operational unity. These advantages make near-space SAR attractive for a variety of remote sensing missions. In this paper, the potential and challenges of the near-space SAR, compared to current spaceborne SAR and airborne SAR, were detailed. Various near-space SAR configurations are introduced, and their potential for different applications such as passive imaging, high-resolution and wide-swath imaging, and inverse SAR imaging were investigated. It is shown that, the use of near-space SAR can lead to the solutions that are previously thought to be out of reach for remote sensing scientists and customers.