ICESat-2 ground-based validation results using corner cube retroreflectors

The Ice, Cloud, and Land Elevation Satellite-2 has completed nearly 3 years on-orbit and continues to provide global elevation data to a broad range of scientific disciplines and applications. Although there is significant diversity among the use cases for the ICESat-2 observations, the commonality in the analyses is the continual need for high quality geolocated data. As such, on-going geolocation validation efforts are required to ensure that the mission meets the measurement requirement throughout the on-orbit lifetime. One independent validation technique uses ground-based corner cube retroreflectors to determine both the geolocation validity and the effective footprint diameter of the ICESat-2 laser beam on the surface. The results using this technique reveal a mean geolocation accuracy of 3.5 m ±2.1 m, meeting the mission requirement of 6.5 m. For those instances where multiple CCRs are illuminated, the mean effective laser footprint diameter is 10.9 m ±1.2 m, with the variability assumed to be due to atmospheric attenuation and other environmental characteristics.