Twenty-Five Years of INR

Abstract

Image Navigation and Registration (INR) is the engineering discipline that deals with the problem of calibrating and stabilizing image geometry, particularly in the domain of geostationary weather satellites where the term appears to have first come into use within the GOES program. GOES I-M represented the transition from spin-stabilization to three-axis control within the GOES program. A spin-stabilized spacecraft, with its large gyroscopic stiffness, is a stable platform for supporting challenging Earth-observation missions from geostationary orbit. Unfortunately, a telescope deployed on a spin-stabilized spacecraft looks towards the Earth only about 5% of the time. NASA and NOAA were justifiably concerned in the GOES I-M epoch by the idea of adapting what was essentially communications satellite attitude control technology to host precision-pointed scanning instruments and accorded special attention to these concerns within the GOES I-M specifications under the heading of INR. The technology and performance of INR systems have evolved considerably since then and the field has found application in a host of non-U.S. systems, including Meteosat, MTSAT, and COMS. This paper looks back at the field beginning with GOES I-M and traces its evolution through Meteosat Second Generation (MSG), MTSAT, COMS, and GOES N-P with advanced stellar-inertial attitude control. It concludes with an analysis of where the field is likely to be heading for the next generation systems, in particular, GOES-R and Meteosat Third Generation (MTG).