The project targets to establish a new class of sensors employing interferometers based on atoms trapped in optical lattices. So far only few proof-of-principle experiments exist exploring guided and trapped atom interferometers. Innovative approaches and methods have to be explored in order to achieve new devices with sensitivities and spatial resolutions far beyond state of the art. Our consortium, exploring "Trapped Atom Interferometer in Optical Lattices" (TAOIL), brings together the European experts on atomic sensors and metrology to accomplish this objective in a combined effort of experimentalists and theorists. In this way, we will develop a new class of atomic sensors for high precision measurements in applied and fundamental physics. We will master new methods for separating a split atomic sample far apart while maintaining the quantum coherence, to detect and spatially image exotic quantum forces. We will learn how to tame harmful decoherence effects by either controlling the strength of the two-body interactions or using novel sources of ultra-cold atoms. We will develop the theoretical and the experimental methods to implement an entanglement-enhanced as well as a chaos-enhanced atom-light coupled sensor, an avant-garde approach to the ultra-precise metrology. The accomplishment of the goals set in TAIOL will open new possibilities for a wide range of applications, such as gravimetry and surface force measurements with the perspective of future industrial implementations. Our project addresses in many respects the “Quantum metrology sensing and imaging” area of the call. It targets the development of high sensitivity atomic sensors based on atom interferometry, which will exploit the long coherence times, extending over seconds, of quantum superposition states, thanks to holding the atoms in trapping potentials. In addition, new schemes for efficient and sensitive readout of the interferometer phase will be developed, exploiting quantum entanglement and chaos. The project will lay the foundations for the development of a new class of compact atomic sensors and will open new perspectives for a wide range of applications, extending well beyond quantum physics, such as inertial navigation, resource exploration, geodesy, surface science and fundamental tests of gravitation.