Gravimeter

AOSense delivered its first commercial compact gravimeter to an aerospace customer in 2010. Gravimeters are specialized accelerometers used to measure local gravity or variations in the gravitational field of the Earth. High-performance gravimeters and gravity gradiometers are well-suited for applications such as geophysical and geodetic surveying, precision navigation, exploration for natural resources, and underground fluid monitoring. Such sensors may also be useful for identifying special nuclear materials, treaty verification, and void detection.

Directly measuring the acceleration of a freely falling body provides an absolute determination of the local gravitational field. Laboratory-based atomic gravimeters are the gold standard for absolute gravity measurements. Here, atoms serve as the falling test mass with laser-atom interactions registering relative motion between the atoms and the sensor case – essentially using laser ranging to measure the acceleration of atoms in free fall.

While atomic gravimeters have unmatched performance, the utility of lab-based sensors is limited by the cumbersome infrastructure typically used to cool, trap, and control the atomic samples. The AOSense compact gravimeter integrates an entire lab of equipment into a portable sensor head and controller, incorporating all necessary lasers, vacuum, and electronics to cool, control, and readout the atomic test masses. The sensor is capable of operating autonomously and acquiring data for weeks. The 20 Hz sampling rate (bandwidth) is compatible with operation in dynamic environments, and compares favorably with typical lab-based sensors that operate in the 0.1-1 Hz range.