High Resolution DSM Generation from ALOS PRISM - Status Updates on Over Three Year Operations

Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried by Advanced Land Observing Satellite (ALOS) was designed to generate worldwide topographic data in respects of its high resolution and stereoscopic observation. For this objective, the on-orbit geometric performance of PRISM sensors has been widely assessed and calibrated since launch in January 2006 as the activity of calibration and validation team of Earth Observation Research Center (EORC) / Japan Aerospace Exploration Agency (JAXA). This ongoing activity has generated various geometric performance data over three year on-orbit period of operations. A suite of geometric model parameters was calibrated to express those geometric characteristics of PRISM sensors. These include static interior parameters (CCD unit camera parameters) and dynamic exterior parameters (orbit data, attitude data, and sensor alignments). The interior parameters were calibrated by the test-field self-calibrations with test sites of dense Ground Control Points (GCPs). The exterior parameters were calibrated by adaptive image orientations with test sites of world-wide GCPs. Those parameters are correlated to the direct geo-referencing accuracies of PRISM sensors and are being monitored and validated to maintain those performances. And the performance analysis of Digital Surface Model (DSM) derived from those geometric model parameters was performed. The detailed characteristics of triangulation results were analyzed by GCPs and height accuracies were evaluated from the comparison with high accuracy and high resolution reference DSM data sets derived from airborne Lidar instruments. The DSMs are being routinely processed on a scene basis at EORC and mosaiced for the generation of global standardized dataset. This paper reports on the methods and results of PRISM geometric calibrations and DSM generations obtained over three year operations.