A Comprehensive Error Modeling and On-Field Calibration Method for HRG SINS by Tumbling the Hexahedron

Area of Science:

• Inertial Navigation Systems
• Sensor Calibration
• Mechanical Engineering

Background:

• On-field calibration of Strapdown Inertial Navigation Systems (SINS) typically employs a hexahedron, but structural errors are often overlooked.
• These errors, including tolerances in parallelism and perpendicularity of hexahedron planes, can impact calibration accuracy.

Purpose of the Study:

• To develop a hexahedron structure error model and a comprehensive SINS calibration error model for hemispherical resonator gyroscopes (HRGs).
• To improve the accuracy and reduce the cost of SINS on-field calibration by accounting for structural imperfections.

Main Methods:

• A hexahedron structure error model is developed by defining normal vectors of exterior surfaces.
• A 24-position calibration scheme identifies accelerometer errors, and a 48-rotation scheme identifies gyro errors.
• Simultaneous identification of structure errors, installation misalignments, scale factor errors, and biases is enabled.

Main Results:

• Experimental validation using a simulated hexahedron structure errors on a three-axis turntable.
• Significant improvement in calibration accuracy for both accelerometers and HRGs compared to traditional methods.
• Reduced accuracy requirements for the hexahedron structure, leading to lower SINS on-field calibration costs.

Conclusions:

• The proposed method effectively models and compensates for hexahedron structure errors in SINS calibration.
• This approach enhances the precision of inertial navigation systems while making calibration more economical.