Static Gravity Reference Vector Determination for Sensor Calibration
Static gravity reference determination requires site gravimetric surveying and arcsecond stage indexing to isolate true sensor bias from facility tilt errors.
Goniometric Stage
Positioning Instrument
Precision alignment equipment comprises a class of mechanical devices designed to rotate an object about a fixed point in space. An operator uses a goniometric stage to achieve highly controlled angular adjustments without shifting the center of rotation. These devices are essential for mounting optical crystals and fiber arrays.
Kinetic Action
The mechanism relies on a curved cradle that slides along a matched guide, which is driven by a precision worm gear. Rotating the gear advances the cradle along a circular path, producing a pure rotational movement. High-end models integrate micrometers or motorized drives to control the rotational increment down to the arcsecond level.
Because the center of rotation is located above the cradle, multiple stages can be stacked to provide orthogonal adjustment around a single point.
Angular Precision
Backlash and friction represent the main sources of positioning error in these stages. Play in the worm gear mechanism can cause slight discrepancies when reversing the direction of travel. Using spring-loaded tensioning helps to minimize these errors, ensuring consistent and repeatable adjustments.
Verification Standard
Metrologists verify the positioning accuracy using an autocollimator and a high-precision polygon mirror. By comparing the stage readings against the mirror faces, they identify non-linearities and wobble in the rotational axis.