On-orbit Spatial Resolution Estimation of CBERS-2 Imaging System Using Ideal Edge Target

Abstract

The China-Brazil Earth Resources Satellite (CBERS-2) has been developed by China and Brazil and was launched on October 2003. This satellite carries three sensors: WFI, CCD and IRMSS. Due to limitations of the CCD sensor components, the images acquired by the imaging system undergo a blurring. Under the hypothesis that the Point Spread Function (PSF) of the imaging system is Gaussian, the blurring effect of an ideal step edge can be represented as an error function (erf). As the PSF is assumed separable, its identification reduces to the estimation of two standard deviations or equivalently to two EIFOVs (Effective Instantaneous Field of View), one for the along-track direction and another for the across-track. This work describes an approach for the on-orbit CBERS-2 CCD spatial resolution estimation using a set of subimages of natural edges and allows an objective assessment of the imaging system performance.