Interferometric Gravimeter Apparatus and Method

摘要

A gravity value is measured using two light beams which each reflect from both a freefall test mass and a stationary reference test mass which is inertially supported by a long period isolation device. The optical path lengths of the light beams change equally and oppositely in response to gravity and equally in response to disturbances, resulting in cancellation of the undesirable effects of the disturbances by common mode rejection and in a desirable increase in the number of gravity induced measurement fringes, when the two light beams are combined interferometrically.

主权项

1. A gravimeter for measuring a value of gravity, comprising:
a first test mass which is released for freefall solely under the influence of gravity; a second test mass connected to a long period isolation device which inertially stabilizes and isolates the second mass against long period disturbances; a source of first and second light beams which have the same initial frequency and a predetermined initial phase relationship; and an arrangement of optical elements which conduct the first and second light beams through first and second different beam arms respectively, the first beam arm directing the first light beam to impinge upon and reflect from both test masses during freefall of the first test mass, the second beam arm directing the second light beam to impinge upon and reflect from both test masses during freefall of the first test mass; and wherein: an interferometric combination of the first and second light beams delivered from the first and second beam arms after impingement upon and reflection from the test masses determines the value of gravity.