Sentinel-1A assessment results from the use of permanent SAR corner reflectors in Cyprus by means of the CyCLOPS strategic infrastructure

CyCLOPS (Cyprus Continuously Operating Natural Hazards Monitoring and Prevention System) plays a pivotal role in geophysical and geotechnical monitoring in Cyprus and the EMMENA region. This strategic research infrastructure comprises six permanent stations, each with a Tier-1 GNSS reference station and two calibration-grade corner reflectors (CRs) of 1.5m inner length. CRs are oriented to the ESA's Sentinel-1 satellite mission to account for ascending and descending tracks. Since reaching full operational status in June 2021, CyCLOPS has been instrumental in observing geodynamic phenomena and landslide activities in Cyprus. This study analyses Sentinel-1A SAR performance by exploiting the CyCLOPS network to estimate key parameters such as spatial resolution, side-lobe levels, Radar CrossSection (RCS), Signal-to-Clutter Ratio (SCR), phase stability, and localization accuracy. Results demonstrate the effectiveness of the CyCLOPS infrastructure in maintaining high-quality SAR imagery radiometric parameters, with consistent spatial resolution, controlled side-lobe levels, and reliable RCS and SCR values closely aligned with theoretical expectations. Furthermore, localization analysis has proven effective in mitigating atmospheric and dynamic Earth influences, ensuring geolocation accuracy. Consequently, the CyCLOPS infrastructure is a state-of-the-art, reliable unit for radiometric calibration and validation of SAR products, which will contribute to the precision and reliability of SAR imaging, crucial for various applications such as crustal motion monitoring.