Cold atom inertial sensors have many applications in fundamental physics (testing the laws of gravitation, gravitational astronomy), geosciences (measuring the Earth's gravity field or rotation) and inertial navigation. The operation of these sensors is based on atomic interferometry, taking advantage of superpositions between quantum states of different momentum in an atom, generated by optical transitions with two (or more) photons. To broaden their range of applications, it is necessary to constantly push back their performance in terms of sensitivity, stability, precision, dynamic range, compactness or robustness, ease of use and cost. The aim of this Master project will be to study and improve our state-of-the-art SYRTE's cold atom gyroscope by one order of magnitude compared with the current state of the art to reach the interferometer's detection limit, which is intrinsically linked to quantum projection noise. It will use new methods like successive joint measurements without dead time. Obtaining this regime requires some modifications to the existing experiment, in particular to the Raman lasers used to manipulate the atomic wave packet, but also to the preparation and the detection of the atomic samples. This method is very general and could also be applied to more common three-pulse interferometers such as accelerometers and gravimeters.