The continuous developments of optical clocks and the long-distance links via fibers, especially within TerraQ, will give access to terrestrial clock networks in practice, which will enable the novel measurement concept of chronometric levelling. From a theoretical perspective, this project will elaborate the rigorous relativistic formalism for clock-based geodesy and assess the effects of approximations in different scenarios. Furthermore, this project will figure out the most promising applications for clock networks in geodesy and fundamental physics.

We will run dedicated simulations to optimise the topology of clock networks and investigate how and where they can contribute to which extent in different applications. We will also derive the requirements on the performance of clock networks to meet the geodetic demands and give feedback to projects Optical Clocks for Chronometric Levelling (A04) and Interferometric Fibre Links (A05). The theoretical developments made here have impact for Relativistic Geodesy from Space Using Novel Measurement Concepts (C03). In fundamental physics, we will investigate the use of clock constellations for testing GR.