TY - JOUR N2 - Knowledge of gravitational acceleration in metrology is required for traceable force and pressure calibrations, furthermore the redefinition of the SI base unit of kilogram requires absolute accomplishment of the gravitational acceleration. A direct free-fall gravimeter is developed using pneumatic grippers for test mass handling and a semi-rotary actuator for repositioning, i.e. automated re-launching. The catch and release system is powered by compressed air. This eliminates electric interferences around the test mass. A simplified method of signal capturing and processing is used on the designed gravimeter. A digital frequency trigger is implemented in the post processing algorithms to ensure that the signals are analysed from the identical effective height. The experimental results measured the site gravitational acceleration of 9.786043 ms−2 with a statistical uncertainty of ±29 µs −2. L1 - http://www.czasopisma.pan.pl/Content/108925/PDF/art_04.pdf L2 - http://www.czasopisma.pan.pl/Content/108925 PY - 2018 IS - No 4 EP - 689–699 DO - 10.24425/mms.2018.124875 KW - direct free fall KW - gravitational acceleration KW - interferometer A1 - Mokobodi, Tlou A1 - Greeff, Pieter A1 - Kruger, Oelof A1 - Theron, Nicolaas J. PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation VL - vol. 25 DA - 2018.12.14 T1 - Free-fall gravitational acceleration measurement using a pneumatically controlled catch-and-release-system in a semi-rotating vacuum chamber SP - 689–699 UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/108925 T2 - Metrology and Measurement Systems ER -