In-flight ground sampling distance estimation of Alsat-1 imager

This article presents the in-flight ground sampling distance (GSD) estimation of the Alsat-1 Slim-6 imager. There are several methods to evaluate the imager GSD, based on natural and/or artificial targets (geometric shapes). We used an image from a higher resolution satellite which was considered as a reference image. This method is based on the error minimization between the two images: Alsat-1 and the reference image. The results showed a stability of the estimated GSD and a consistency with the expected performance of the imager.