New Open-Loop Tracking Command (OLTC) platform : AltiGIS

Over the last decade, there has been a burgeoning interest in altimetry measurements for inland waters, with a focus on comprehensive studies of water levels in lakes, reservoirs, and rivers on a global scale. This research is crucial for the hydrology community to accurately assess the Earth's freshwater resources. Significant advancements have been achieved in enhancing altimeters' capacity to obtain high-quality measurements over inland waters.

The Open-Loop Tracking Command (OLTC) stands out as a noteworthy development in altimeter on-board tracking modes. Its effectiveness has been proven through successful implementation in previous missions and is now designated as the operational mode for current missions, including Sentinel-3, Sentinel-6, and SWOT nadir.

Over the past decade, OLTC data, crucial in tracking inland water bodies from radar altimetry satellites, has undergone substantial refinement. Originally developed for Jason-2, new missions as Jason-3, Sentinel-3A&B, Sentinel-3B, Sentinel-6, SWOT nadir have been incorporated. Algorithms and procedures to compute location and elevation of inland waters targets (rivers, lakes, reservoirs) have also been largely improved. The number of hydrological targets has increased fivefold with an acquisition success rate which is now close to 90%. Presently, each mission tracks between 30,000 to 70,000 hydrological targets.

Despite modifications to a software developed 15 years ago, ongoing advancements and the necessity for covering  land ice surfaces in preparation of upcoming S3C&D missionshave prompted the development of a new software. In addition, the availability of new input data provided by the SWOT mission (water mask and elevation) required also to revise the current software to make their usage efficient. Work is currently underway to establish a new OLTC platform, named AltiGIS. The platform is designed with three primary objectives: facilitate collaboration, enhance data generation validity, and broaden dissemination through the use of DevOps practices. The presentation aims at harvesting new user needs but will also cover both the undergoing software development and roadmap.