The Experiment Surveying and Alignment (ESA) section of the GM group is in charge of the surveying, the large scale metrology and the alignment, for CERN physics experiments. This includes:

• Design, installation, measurement and maintenance of the geodetic infrastructure in the experimental areas;
• Participation in the layout and design phases and discussion of the detector alignment requirements since the project initiation to ensure the correct integration of adapted alignment procedures for the entire detector life time
• Metrology of the detector prototypes and components (quality controls, deformation measurements, contribution to assembly works, fiducialisation) when the classical workshop methods cannot be applied;
• Geometrical measurements for the alignment and positioning of Physics Experiments with respect to the corresponding accelerator and beam geometries;
• Mathematical processing and statistical analysis of related survey data in order to supply the precise spatial position and orientation of the detectors;
• Providing as-built measurements for detectors and experimental areas;
• Expertise in geodetic metrology and large scale metrology instrumentation and methods, and authority at CERN in close range photogrammetry;
• R&D and computing related to specific surveying tasks for the existing Physics detectors, their upgrades or for future experiments;
• Support for the development of permanent monitoring and alignment systems;
• Liaison with the Collaboration and Technical Coordination of the Physics Experiments for survey and alignment purposes.