Results of calibration and validation of ALOS optical sensors, and their accuracy assesments

The Advanced Land Observing Satellite (ALOS, the nickname is "Daichi") was successfully launched on January 24^th, 2006, and it continuously working very well. This paper introduces the updated results of calibration for two optical sensors of ALOS i.e., the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and the Advanced Visible and Near Infrared Radiometer type-2 (AVNIR-2). PRISM consists of three panchromatic radiometers, and is 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 image of PRISM. The radiometric calibration is also important for PRISM as well as AVNIR-2. This paper describes the results of geometric and radiometric calibrations for 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 one and half years after the launch, and accuracy assessment plan during mission life of the ALOS.