The A-10 is a high-precision, field-ready portable instrument designed to measure the vertical acceleration of gravity (g). While capable of serving as a reliable and precise laboratory tool, the A-10 is primarily optimized for field use. It operates on a 12V DC power source (e.g., a car battery) and is designed for rapid field deployment: depending on site conditions, it can measure gravity at over 20 absolute field stations in a single day.
Operating Principle
The operation of the A-10 is straightforward in concept. A test mass is lowered vertically by a mechanical device within a vacuum chamber and allowed to free-fall over an average distance of 7 cm. The A-10 uses a combination of a laser, interferometer, long-period inertial isolation, and an atomic clock to precisely determine the position of the test mass during free fall as it accelerates due to gravity. The acceleration of the test mass is calculated directly from its measured trajectory.
A laser interferometer generates optical interference fringes as the test mass falls. These fringes are counted and timed using an atomic clock to generate highly accurate pairs of time and distance data. The data is then fitted to a parabolic trajectory to derive a measured value of g.