21 Avril – Thesis defense - Simon Templier

14 h En visioconférence

Three-axis hybridized quantum accelerometer for inertial navigation.

The spirit of the shared laboratory iXatom, involving the collaboration between the laboratoire photonique numérique et nanoscience (LP2N) and the company iXblue, is to develop solutions and improvements for inertial navigation with quantum sensors. Indeed classical inertial sensors suffer from a time-varying bias which mislead the computed trajectory by inertial navigation systems. Atom interferometers based on matter-waves offer an absolute measurement with a dramatic precision and stability. Such sensors are considered as a serious candidate to help inertial navigation systems.
Cold atoms sensors are reaching a certain level of maturity in the academic community which justify a technological transfer toward the industry. However such instruments, including an ultra-high vacuum chamber, a complex control system, an agile multi-frequency laser architecture with phase coherence and control, remain complex and massive. Efforts are necessary for their integration into industrial and on-board applications.
This thesis work addresses the improvement of accelerometers dedicated to inertial navigation. The hybridization between classical and quantum accelerometers afford complementary performances. Actually the measurements of the atomic interferometer experience a reduced dynamic and dead-times during the preparation of the atomic cloud, leading to a limited bandwidth. Classical accelerometers present continuous measurements with a large dynamic range necessary for navigation. The hybrid accelerometer provides high-bandwidth measurements with a wide dynamic range and without biases. Other challenges, such as multi-axis measurements with a random orientation of the atomic sensor, are investigated. Furthermore a method to calibrate the 3-axis atom interferometer is proposed and realised, which involves a full study of the systematic effects and the correction of misalignments between measurement axes.

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