This training network focuses on the development of modern quantum sensors based on precision measurements of inertial forces, electro-magnetic fields, and time. Important ideas and major contributions to current research in this field have originated from atomic physics and quantum optics. The topics covered are gravitational probing, rotational sensing, field probes, and atomic clocks, with potential future applications ranging from fundamental science to geological exploration, navigation and medical diagnostics.The consortium will train a cohort of young researchers on the physics of atomic clocks and interferometers, which form the basis of quantum sensors, and several techniques to realise technologically relevant devices. The envisioned designs incorporate micro-structured components for trapping and guiding of atoms and photons. With this approach we aim for a high level of integration and advantageous parameter regimes, which will widen the range of possible applications by addressing aspects of sensitivity and bandwidth of measurements, alleviating access restrictions to points of interest, and improving mobility for field applications. We complement the range of topics by including surface probes, field sensitive microscopes, and molecular spectroscopy, deepening the connections to other scientific disciplines.The partner consortium is an exceptional combination of industrial and academic stakeholders, ranging from technology suppliers to users, supported by, e.g., the European Patent Office and the Research Policy Institute to assist the innovation process. The research training covers physical principles and technological aspects from development to implementation, with input from industrial partners on truly relevant needs. It is complemented by training on societal aspects, intellectual property rights, and transferable skills training, thus addressing a wide skill set that unites technical expertise with an innovative mindset.