Sentinel-1 instruments status, product performance and evolutions

Abstract

The Copernicus Sentinel-1 (S-1) mission ensures the continuity of C-band SAR observations over Europe. A key aspect of the Copernicus program is the constant provision of open and free high-quality data. This requires long term engagement to carefully monitor, preserve, and improve the system and product performances. The Sentinel-1 SAR Mission Performance Cluster (SAR-MPC) monitors the variation of key parameters over time using standard products and/or dedicated auxiliary ones (e.g., antenna monitoring trough RFC products, radiometry and geolocation using standard data and dedicated FRM, etc). This year's main events include: - A failure of a single antenna TRM module in April 2024, which was identified through monitoring of the antenna error matrices obtained using S1A RFC products and followed-up by dedicated quality impact assessment. - A S-1A platform anomaly impacting the thruster in charge of the orbit inclination control. After the event, ESA has decided in agreement with the European Commission to suspend the orbit inclination control maneuvers, for spacecraft safety reasons. This decision has further consequences on the Sentinel-1 orbit which had, since the beginning of the mission, been maintained within 200m RMS diameter tube. Starting mid-April 2024, the orbit inclination is naturally evolving following a yearly pattern further modulated by a secular drift. The monitoring of baseline and burst synchronization continues to be done routinely and has been evolved to better track the effects of the change in orbit control, e.g., to better identify dependencies with latitude and changes within the data-take (the latter for burst synchronization). - Larger Doppler jumps have been observed between different star-tracker (STT) configurations (up to 50Hz). A STT re-calibration has then been proposed and implemented and shows positive results in terms of Doppler time series continuity. This presentation will provide an overview of the status of the Sentinel-1 instrument and product performance, including up-to-date results on the points listed above, as well as details on recent and upcoming evolutions on the product performance and cal/val (e.g., dedicated auxiliary data file for machine learning models and introduction of rain rate measurements at L2).