OCI geolocation evaluation and refinement using Landsat control points

The Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) mission is NASA’s next investment in ocean biology, clouds, and aerosol data records. A key feature of PACE is the inclusion of an advanced satellite radiometer, the Ocean Color Instrument (OCI), a global mapping radiometer that combines multispectral and hyperspectral remote sensing. Geolocation processing is performed for OCI using spacecraft navigation data and an instrument geometry model. To evaluate geolocation accuracy for OCI and develop refinements to processing methods, control point matching using Landsat data has been implemented as a step in operational processing of OCI data at the Science Data Segment. This processing provides between 200 and 300 high-quality matchups per day with good global and geometric distribution, allowing rapid evaluation of OCI geolocation accuracy. Initial results provided an early indication of the overall quality of geolocation processing and of specific aspects needing improvement. A standard set of granules was identified to support rapid implementation and testing of geolocation refinements, and this approach has been highly successful in improving geolocation processing accuracy to meet science requirements. This evaluation will continue throughout the mission to ensure the ongoing accuracy of geolocation. This paper describes the control point matching methodology, the approach to development of geolocation processing refinements, and recent results.