Precision Angle Measurement Systems on the Basis of Ring Laser Gyro

Area of Science:

• Metrology
• Optical Engineering
• Navigation Systems

Background:

• Ring laser gyroscopes (RLGs) are primarily used in navigation for strapdown inertial navigation systems.
• RLGs also possess capabilities for high-precision angle metrology applications.
• Existing angle measurement devices face limitations in accuracy and calibration.

Purpose of the Study:

• To discuss the properties and applications of a laser dynamic goniometer (LDG) based on RLG technology.
• To detail the calibration of optical polygons, digital angle converters, and external mirrors.
• To analyze uncertainty sources and compensation methods for enhanced measurement accuracy.

Main Methods:

• Utilizing a laser dynamic goniometer (LDG) for angle metrology.
• Investigating ring laser gyro bias due to external magnetic fields and rotational velocity instability.
• Applying the reversal method for separating LDG and angle converter uncertainties.
• Considering a simplified cross-calibration method.

Main Results:

• Calibration results for various optical encoder designs (on-axis and off-axis) are presented.
• Performance data for the LDG in measuring angles between external mirrors are shown.
• The LDG demonstrated higher accuracy than contemporary theodolites and total stations in theodolite operating mode.

Conclusions:

• The laser dynamic goniometer (LDG) is a viable tool for high-precision angle metrology.
• The LDG offers improved accuracy for calibrating angle measurement devices and measuring external angles.
• Compensation methods effectively mitigate uncertainties, enhancing the reliability of RLG-based goniometry.