Measurement of Local Gravity for Force, Torque and Pressure Standards - Good enough for the requirements expected in 2050?

摘要

The measurements of local gravity and air density are fundamental requirements when establishing measurement standards for Force, Torque and Pressure that are based on calculating the force due to the Earth's gravity on a known mass, in air. The Emirates Metrology Institute (EMI), established by the Abu Dhabi Quality and Conformity Council in April 2014, has several measurement standards which require the value of local gravity - or free-fall acceleration - to be known. The paper describes the method used to measure local gravity at the relevant locations in the EMI, with a relative expanded uncertainty (k=2) of 2.0 × 10~(-7). The paper also outlines the approach taken for calculating the air-buoyancy force and associated uncertainty. The paper proposes the way in which the best uncertainties for Force, Torque and Pressure standards can be achieved, and concludes that the requirements of the most demanding users of these standards will be able to be met for the foreseeable future.