Simulation and Analysis of Icesat-2 Point Clouds

Abstract:

The ATLAS instrument on the upcoming ICESat-2 mission contains a high-repetition rate micropulse laser and photon counting detectors for high sensitivity and dense along-track sampling. As evidenced by the airborne MABEL photon-counting system, the data collected by photon-counting detectors have substantial noise and will require considerable processing to accurately retrieve the surface elevation in many situations. To study the characteristics of these data and in support of pre-launch algorithm development, researchers at RIT have been generating simulated ATLAS point clouds using their DIRISG tool, a first-principles radiative transfer remote sensing data simulation package. Included in the simulated data are noise returns specified using pre-launch measurements of the flight detectors. These simulated data have been used to assess the accuracy of surface-finding algorithms and to study the anticipated elevation retrieval performance on complex snow and ice surfaces. This work has found single-track biases of up to 2 cm and error standard deviations of up to 10 cm on complex snow surfaces. Additionally, the research has shown quantitative sensitivity confirming smoother surfaces result in higher accuracy and a lower surface diffuse albedo result in a smaller bias.