Alignment Procedure
Manual or automated adjustment of an instrument’s orientation to align its primary measurement axis with the local gravity vector establishes a stable reference datum. Known as static leveling, this preparation is performed before initiating high-precision surveying or metrology operations. It ensures that subsequent measurements are made relative to a true horizontal or vertical plane.
Sensing Feedback
Bubbles vials or electronic inclinometers provide the feedback necessary to guide the adjustments. In automated systems, motorized leveling feet receive signals from a dual-axis tilt sensor and adjust the height of individual support points. This active correction loop continues until the measured tilt falls within a specified tolerance, which is often less than a milliradian.
Reference Stability
Maintaining this level state during operation requires a stable foundation that is isolated from thermal expansion and ground vibrations. Environmental changes can cause the supporting surface to tilt, which introduces measurement drift. For long-term monitoring, the system must periodically verify the level state or utilize continuous compensation algorithms to correct the gathered data.
Uncertainty Budget
Incomplete leveling leaves a residual tilt error that projects a component of the horizontal displacement into the vertical measurement. This error scales with the cosine of the tilt angle.
