Many sectors of society and the economy are now heavily reliant on Global Navigation Satellite Systems (GNSS). However, GNSS has several intrinsic vulnerabilities and cannot be used underwater or underground. In these situations, Inertial Navigation Systems (INSs) can act as a reliable alternative. These self-contained devices reconstruct the trajectory of a vehicle being tracked by measuring its acceleration and rotation rate. A complete INS combines measurements from three orthogonal accelerometers and three orthogonal gyroscopes. Together with knowledge of the vehicle's starting position, its current location can be calculated, without the need for an external reference. Conventional systems use high precision classical sensors, however long-term performance is currently limited by scale factor and bias drifts.
At Imperial College we are developing cold atom interferometers for inertial sensing. Their high-accuracy and long-term stability mean they offer the potential for improved long-range navigation in the near future. Clouds of rubidium-87 atoms are cooled to ultra cold temperatures then split, reflected, and recombined using stimulated Raman transitions to make an atom interferometer. Here, we describe our recent work to extend the operation of our laboratory, two-axis accelerometer into a rotation sensor. By launching the atom cloud using a moving molasses, we are able to measure rotations about three perpendicular axes.
|Presenter name||A. Kaushik|
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