An Improved Geolocation Methodology for Spaceborne Radar and Lidar Systems

Abstract. Geolocation and co-registration methodologies are essential for the accurate interpretation of observations from spaceborne remote sensors. In preparations for EarthCARE, here, we refine the definition of these techniques and present various examples of geolocation assessments. The geolocation methods build upon earlier work, however, introduces several improvements that have increased the reliability of the geolocation accuracy. The EarthCARE active sensors geolocation methods use coastlines and significant elevation gradients, in both statistical and numerical ways. The effectiveness of the proposed geolocation methods was tested using the extensive record of CloudSat and CALIPSO observations. The EarthCARE active sensors geolocation methods were effective in identifying and correcting a short period of CloudSat observations when the star tracker was not operating properly. In addition, the geolocation methods were able to reproduce the excellent geolocation record of the CloudSat and CALIPSO missions.