ASTER geometric performance

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system acquires multispectral images ranging from the visible to thermal infrared region. The ASTER system consists of three subsystems: visible and near-infrared (VNIR), short-wave infrared (SWIR) and thermal infrared (TIR) radiometers. The VNIR subsystem has a backward-viewing telescope as well as a nadir one. To deliver data products of high quality from the viewpoint of geolocation and band-to-band registration performance, a fundamental program, called Level-1 data processing, has been developed for images obtained using four telescopes with a cross-track pointing function. In this work, the methodology of the geometric validation is first described. Next, the image quality of ASTER data products is evaluated in view of the geometric performance over a period of four years. The band-to-band registration accuracy in the subsystem is better than 0.1 pixels and that between subsystems is better than 0.2 pixels. This means that the geometric database is determined accurately and the image matching method based on a cross-correlation function is effective in the operational usage.