CALIBRATION AND VALIDATION OF PRISM ONBOARD ALOS

Abstract

This paper introduces the updated plans for sensor calibration and product validation of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM), which is to fly on the Advanced Land Observing Satellite (ALOS) satellite that will be launched this Japanese fiscal year. PRISM is used to derive digital elevation models (DEMs) with very high spatial resolution, which is also one of the objectives of the ALOS mission. To achieve this objective, PRISM consists of three panchromatic radiometers for forward-, nadir-, and backward-looking in the along-track direction, and acquires the images in the same orbit and at almost the same time. The geometric calibration is important in generating a highly accurate DEM with high spatial resolution by using PRISM’s triplet images. Highly accurate ground control points (GCP) are necessary to calibrate the geometric accuracy and validate the generated DEM. Collecting GCP worldwide is difficult and hard work in spite of its importance. In this paper, we describe the current plans for calibrating and validating PRISM aboard the ALOS, and in particular, our strategies for preparing GCP with evaluation items for geometric calibration, including expected problem effects regarding geometric accuracy.