Cal/Val Results and Accuracy Assessment Plan for PRISM and AVNIR-2 Onboard ALOS

This paper introduces the updated results of calibration for optical instruments of the Advanced Land Observing Satellite (ALOS, nicknamed “Daichi”), was successfully launched on January 24th, 2006, and it continuously working very well. ALOS has three mission instruments; an L-band Synthetic Aperture Radar called PALSAR, and two optical sensors called PRISM and AVNIR-2. PRISM stands for the Panchromatic Remote-sensing Instrument for Stereo Mapping, and consists of three panchromatic radiometers, and those images are used to derive a Digital Surface Model (DSM) with high spatial resolution, which is also an objective of the ALOS mission. The geometric calibration is important in generating a highly accurate DSM by stereo pair images of PRISM. AVNIR-2 stands for the Advanced Visible and Near Infrared Radiometer type-2, and has four radiometric bands from blue to near infrared. The radiometric calibration is also important for PRISM as well as AVNIR-2. This paper describes the updated results of geometric and radiometric calibrations of PRISM and AVNIR-2 in the operational phase after initial calibration phase, which are including methodology of analysis and experiment, update parameters related to the absolute accuracy, stability evaluations during about two years after the launch. These works are carrying out during mission life of the ALOS as operational calibration to keep absolute accuracies of the standard products.