Accession Number : AD0871311

Title :   Flotation as a Technique for Testing Low-Level Accelerometers in the Earth's Gravitational Field.

Descriptive Note : Summary rept.,

Corporate Author : STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS

Personal Author(s) : Likeness, Barry K.

Report Date : MAY 1970

Pagination or Media Count : 207

Abstract : Laboratory calibration of accelerometers which operate in the range from ten to the minus three g to the ten to the minus eight g or lower has previously been limited by the earth's gravitational field to uncertainties on the order of ten to the minus six g. A new technique that reduces these limitations by several orders of magnitude is presented. The accelerometer proof mass is immersed in a flotation fluid which supports all but an accurately controlled small fraction of its weight. Test inputs and the instrument support forces are thereby maintained precisely at orbital levels. Seismic noise, similarly attenuated, becomes insignificant. Choosing sulfur hexafluoride (SF6), a heavy gas, for the flotation fluid, permits a wide range of density levels which can be servo-controlled volumetrically, and minimizes the interaction effects of the flotation fluid and the accelerometer. Limitations on the types of instruments that can be tested by this technique are discussed. (Author)

Descriptors :   (*ACCELEROMETERS, CALIBRATION), GRAVITY, MAGNETIC FIELDS, FLOTATION, NUMERICAL ANALYSIS, ERRORS, EQUILIBRIUM(PHYSIOLOGY), TEST METHODS, EXPERIMENTAL DATA.

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE