The Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Level 1B (AST_L1B) Registered Radiance at the Sensor data product is radiometrically calibrated and geometrically co-registered. Application of intra-telescope and inter-telescope registration corrections for all bands are relative to the reference band for each telescope: Visible and Near Infrared (VNIR) Band 2, Shortwave Infrared (SWIR) Band 6, and Thermal Infrared (TIR) Band 11. The AST_L1B product has a spatial resolution of 15 meters (m) for the VNIR bands, 30 m for the SWIR bands, and 90 m for the TIR bands. Known Issues * The QAPERCENTINTERPOLATEDDATA field in .met files was found to be inconsistent due to a software upgrade. Following evaluation by the ASTER Science Team, it was determined to have no impact on science data and has been set to 0 and nullified. * SWIR data acquired after April 2008 may exhibit anomalous saturation and striping. Users should consult the ASTER SWIR User Advisory for additional details. Improvements/Changes from Previous Versions * Radiometric Calibration Update: Version 4 applies Radiometric Calibration Coefficient Version 5 (RCC V5) to improve the radiometric accuracy of the raw DNs, based on research by Tsuchida and others (2020), published in Remote Sensing.