A Distance-Adaptive Method for Three-Axis Angle Measurement Based on an Optical Wedge

Area of Science:

• Optoelectronics
• Mechanical Engineering
• Optical Metrology

Background:

• Non-contact three-axis angle measurement is crucial for airborne optoelectronic gimbals.
• Previous optical wedge methods had distance-dependent errors due to fixed-coefficient models.
• Axial displacement in gimbal platforms introduces nonlinear measurement errors.

Purpose of the Study:

• To develop a distance-adaptive method for accurate three-axis angle measurement in airborne optoelectronic gimbals.
• To address and compensate for nonlinear errors caused by variations in measurement distance.
• To improve the precision of angle measurements in dynamic gimbal systems.

Main Methods:

• Established an analytical measurement-distance model using ABCD ray-transfer-matrix theory.
• Incorporated measurement distance (L) into the angle-solving model.
• Updated fixed coefficients in the error-compensation model based on estimated distance.

Main Results:

• The proposed distance-adaptive method significantly enhances measurement accuracy under varying distances.
• At L = -2 mm, RMS errors for pitch, yaw, and roll were reduced from 13.0″, 8.4″, 31.1″ to 5.6″, 3.8″, 18.6″.
• Demonstrated substantial improvement in measurement precision for airborne optoelectronic gimbal platforms.

Conclusions:

• The distance-adaptive method effectively compensates for nonlinear errors in three-axis angle measurements.
• This technique is vital for applications requiring high accuracy in dynamic environments, such as airborne platforms.
• The study provides a robust solution for improving the performance of optoelectronic gimbal systems.