A polar coordinate system based on a projection surface for moon-based earth observation images

摘要

As a new potential platform for Earth observation, the Moon which is a natural satellite unique to the Earth has been paid more and more attention for its consistent and continuous observation capability of global-scale and macroscopic geoscience phenomena on Earth. Because of the effect of Earth curvature and the Earth-Moon geometric relationship, the geometric correction of the Moon-based Earth observation (MBEO) hemisphere images is more complex than that required for images obtained from low Earth orbit (LEO) platforms and need to be investigated, such as optical images in visible/thermal infrared frequencies or synthetic aperture radar (SAR) images in microwave frequency. In addition, it is also difficult to find the uniformly distributed geometric correction control points on the entire surface of the Earth caused by sea and cloud cover in most regions. In this paper, a polar coordinate system on a projection surface related to the sublunar point is designed to facilitate the geometric correction of MBEO hemisphere images and to try to compensate for the problems of geometrical distortion caused by the shift of the sublunar point, the curvature of the Earth and the terrain fluctuation. Through simulation analysis, the geometric error characteristics and conditions in which the proposed moon-projection polar coordinate system can be used are discussed. This involves considering the Earth model, the projection method, the offset of the sublunar point and the external error. The results show the validity and adaptation of the proposed polar coordinate system and will support the further study of the geometric correction of MEBO images. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.