Development of a Small and Portable Absolute Gravimeter
A L. Vitouchkine, J E. Faller
lhgh precision (10-9-10-8)g absolute ballistic gravimeters (ABGs) are now being used worldwide. The ballistic method is based on the measurement of time and distance changes during the free fall of a test mass (TM) in a vacuum. The movement of the TM obeys the law of free-fall accelerated motion. The distance measurements are made interferometericaby. The TM contains an optical comer cube and the center of mass is positioned to be at the optical center of the comer cube. There are two variations of ballistic nzthod: synunetrical annonsynumtrical. In case of the symmetfical method the TM freely moves up, and after reaching the top of trajectory, moves down. Measuremmnts are perfomied during both parts of the trajectory. In the nonsymnietrical method, measurements are made when the TM is freely falling down.