Volume 1 of the FCC Feasibility Report presents an overview of the physics case, experimental programme, and detector concepts for the Future Circular Collider (FCC). This volume outlines how FCC would address some of the most profound open questions in particle physics, from precision studies of the Higgs and EW bosons and of the top quark, to the exploration of physics beyond the Standard Model. The report reviews the experimental opportunities offered by the staged implementation of FCC, beginning with an electron-positron collider (FCC-ee), operating at several centre-of-mass energies, followed by a hadron collider (FCC-hh). Benchmark examples are given of the expected physics performance, in terms of precision and sensitivity to new phenomena, of each collider stage. Detector requirements and conceptual designs for FCC-ee experiments are discussed, as are the specific demands that the physics programme imposes on the accelerator in the domains of the calibration of the collision energy, and the interface region between the accelerator and the detector. The report also highlights advances in detector, software and computing technologies, as well as the theoretical tools/reconstruction techniques that will enable the precision measurements and discovery potential of the FCC experimental programme. The content and structure of this report are guided by the scope and priorities defined in the mandate of the FCC Feasibility Study. It is therefore not intended to serve as an exhaustive review of the full physics potential of FCC. Several topics, already covered in earlier reports such as the FCC CDR, are not reiterated here or are addressed only briefly, in alignment with the study’s focus. This volume reflects the outcome of a global collaborative effort involving hundreds of scientists and institutions, aided by a dedicated community-building coordination, and provides a targeted assessment of the scientific opportunities and experimental foundations of the FCC programme.

The precision and accuracy of a Leica MultiStation 60-based QDaedalus astrogeodetic measurement system are determined through observations at two locations in Switzerland. The precision of the QDaedalus was determined as 0.1″ for the N-S and E-W deflections of the verticals (DoVs) through 118 series of observations collected over 13 nights (in a 44-day observation period) at the HEIG-VD test station. The accuracy of the QDaedalus system was established by simultaneous parallel observations over two nights using the CODIAC system at the Zimmerwald Observatory. The differences between them were found to be 0.09″ and 0.02″ for the N-S and E-W DoV components, respectively. From these results, the accuracies of both DoV components can be interpreted as 0.1″. We also found a large systematic trend in the observed N-S DoV data at the HEIG-VD test station (0.008″/day). This study is the most extensive thus far for determining the precision and accuracy of the QDaedalus system for astrogeodetic measurements; it is also the first time that QDaedalus system’s accuracy has been established using parallel observations.

Nowadays, zenith telescope-based digital zenith cameras (DZC), such as the COmpact DIgital Astrometric Camera (CODIAC) and VErtical by STArs (VESTA), are used to determine highly precise astrogeodetic deflections of the vertical (DoVs). The CODIAC and VESTA were developed by Eidgenossische Technische Hochschule (ETH) Zurich and University of Latvia, respectively, and only two CODIACs and four VESTAs were produced. The CODIAC has an established accuracy higher than 0.05″, while the accuracy of VESTA is ~0.1″. These two DZCs, which are the most used DZCs of the last decade, were used effectively over many survey campaigns. In this study, we used both the CODIAC and VESTA to conduct simultaneous observations at the School of Management and Engineering Vaud (HEIG-VD) in Yverdon-les-Bains, Switzerland, over five nights in August 2021. Our DZC measurements with CODIAC and VESTA mark the second time that simultaneous parallel observations were made with two different DZCs. Additionally, the VESTA was never tested against another DZC through comparative simultaneous measurements. These comparative measurements between the VESTA and CODIAC allowed for VESTA precision validation and checking the agreement between the two DZCs. The results of repeated, comparative DoV observations over five nights at HEIG-VD revealed a DoV measurement precision of VESTA around 0.13–0.16″ for 15 min long observation session and 0.10–0.13″ for 50 min long observation session. Mean DoV differences between CODIAC and VESTA at HEIG-VD were 0.08″ and −0.06″ for the North–South and East–West components, respectively.

CubETH is a satellite project aimed at technology demonstration. One of the mission goals is the determination of the attitude of the 10 × 10 × 10 cm³ spacecraft with GNSS. First tests revealed that Phase Center Variations (PCV) dominate the error budget. In consequence, a simple field method for PCV calibration of antenna systems was developed. The estimated PCV confirms the hypothesis of mutual influence of the antennas. A simulation study using the estimated pattern and a validation with real data proved that the PCV calibrations significantly enhance the accuracy of the attitude determination. The root mean square error of the estimated attitude of a platform with three antennas located within 15 cm of each other could be reduced from 6° to 4.5°. The newly developed calibration method is easy to carry out and will help to enhance the accuracy of GNSS attitude determination systems.