Method of absolute gravity measurement and its influence in mass determination

The determination of acceleration due to gravity has application in many measurements. Its value is of interest in a broad area of physical sciences, Metrology, Geophysics and Geodesy. In Metrology, knowledge of the gravity field is very important in mass determination, and also it is used as a transfer standard in the determination of metrological standards involving force and pressure measurements. The need for modern absolute gravity measurements within 10^-9 relative uncertainty is one of the priority tasks in metrology. This paper describes the determination of acceleration due to gravity using IMGC-02 absolute gravimeter and its influence on a weighing result. The instrument adopts the symmetric-free fall method where both the rise and falling trajectory is used to fit the motion model. The trajectory of the flying object is recorded interferometrically by measuring the distance over which it moves with the wavelength of a He-Ne laser. The results of absolute gravity measurements are carried out in the gravity laboratory of National Institute of Metrological Research, (INRIM) Turin, Italy in collaboration with the gravimetry field staff. In the paper are also presented some applications in determination of acceleration due to gravity in mass field. (author)