XGOHI, Extended GOES High-Inclination Mission for South-American Coverage

Operational weather forecasting depends critically on the Geostationary Operational Environmental Satellite (GOES) system. The GOES constellation consists of an eastern satellite stationed at 75°W longitude, a western satellite stationed at 135°W longitude, plus in-orbit spares. As of mid2005, GOES-12 occupied the eastern slot, GOES-10 occupied the western slot, and GOES-11 was in storage in orbit. National Oceanic and Atmospheric Administration (NOAA) plans to replace GOES-10 with GOES-11 as the operational GOES-W satellite in late-2006. The GOES-10 satellite is still functioning well, but has exhausted its north-south station-keeping fuel. GOES-10 will be drifted east to its new station at 60° W longitude where it will continue to operate in a high-inclination mission to provide coverage over South America and off the west coast of Africa where hurricanes are born. Other satellites may also be operated in highinclination missions when they exhaust their stationkeeping fuel, extending their operational lifetimes and enhancing the return on the public investment in the GOES system. Normally, the GOES Imager is operated in fixed-grid mode, meaning that Image Motion Compensation (IMC) is applied in space to control the Imager scan mirror to compensate for image distortion caused by deviations of the orbit and attitude from their reference values. Considering that the Sounder is operated in dynamic-gridding mode, no IMC is applied to control its pointing. Current GOES operational spacecraft (east and west) operate within a 0.5 degree inclination limit that allows the on-board IMC system to scan imagery as if from a perfect GOES projection from a fixed point in orbit. This limitation on inclination, limits the life of GOES spacecraft in that older spacecraft (with lower fuel reserves) cannot be maintained within the 0.5 degree inclination limit. A study commissioned by NOAA during the spring of 2005 reported that ground remapping (effectively applying IMC on the ground) would allow continued operations of older spacecraft, while preserving the benefits of fixedgrid mode. Hence the same quality of Image Navigation and Registration (INR) service provided normally would be transparently delivered. The proposed remapping of images has been employed on Meteosat and Meteosat Second Generation (MSG) for many years and is also part of the Japanese MTSAT Program. Continuous operation of GOES-10 in a high inclination mode using this new ground-based IMC capability will dramatically improve the quantity and quality of data available to South American countries for improving weather forecasts, limiting the impact of natural disasters, and improving energy and water resource management. The scope of this paper is to describe the design and implementation of the operational ground system needed to support the eXtended GOES High-Inclination (XGOHI) mission. Index Terms – GOES, Ground System Processing, Image Motion Compensation (IMC), Resampling, Remapping