LOW LATENCY ON-BOARD DATA HANDLING FOR EARTH OBSERVATION SATELLITES USING OFF-THE-SHELF COMPONENTS

Satellite Earth Observation (EO) is nowadays receiving significant attention. In this regard, the latency of EO product provision to the ground segment is undoubtedly among the first key performance indicators for these systems. The European Union Horizon 2020 EO-ALERT project aims at overcoming the limitations of traditional Near Real-Time (NRT) onboard data chain architectures by moving all the critical processing tasks on the flight segment and accelerating them using high-performance commercial off-the-shelf (COTS) devices. The resulting architecture minimizes the amount of transmitted data and eliminates ground-based data processing from the EO data chain, hence achieving actual real-time product delivery in less than 5 min with optical and Synthetic Aperture Radar (SAR) data. This paper presents the performance benefits of a mixed software-hardware design of the CPU Scheduling, Compression, Encryption, and Data Handling (CS-CEDH) Subsystem responsible for data compression and encryption as well as data routing and scheduling tasks. Compared to a software-only solution, the exploited High-Level Synthesis (HLS) methodology enables 5 to 7-fold speed-up in onboard image compression and encryption tasks and 2 to 5-fold reduction in the contribution of the CS-CEDH Subsystem to the overall onboard image data chain while contributing by less than 1 s to the delivery of the alerts to the end-user.