The S3T Surveillance Radar (S3TSR) is a radar system developed by Indra within a project funded by Spanish Administration and technically managed by ESA. It is a ground-based radar, based in a close monostatic configuration, operating at L band and capable of providing positional information of orbital objects. The radar provides automatic surveillance and tracking of space objects in Low Earth Orbit (from 200 km to 2000 Km of orbit height above Earth). This is performed by continuously scanning the instrumented Field of Regard (FoR), generating track reports for all detected objects. Situational awareness of LEO is an activity with increasing strategic value for national sovereignty.
Based on this tracks, the S3TOC (Spanish Space Surveillance and Tracking Operation Centre) generates a catalogue in which objects are updated every pass. The radar architecture is scalable and the performances of the radar can improve by just adding building blocks (tiles). Both, TX and RX antennas are separated electronically scanning arrays (AESA). The Tx antenna has high power amplifier modules based in GaN technology to improve efficiency and reliability. The RX modules use direct RF undersampling technology. RX beamforming architecture is fully digital, each antenna input is digitized to maximize functional flexibility, and entirely over optical fiber making possible the simultaneous formation of multiple RX radiation patterns. The system is designed as very modular to improve availability.