A Vondrak low pass filter for IMU sensor initial alignment on a disturbed base.

Area of Science:

• Navigation Systems Engineering
• Signal Processing
• Control Systems

Background:

• Accurate initial alignment of Inertial Measurement Units (IMUs) is critical for Global Positioning System (GPS)/INS integration.
• Disturbed environments, like vehicles affected by wind, pose challenges for traditional INS alignment methods.
• High-frequency noise in force observations degrades the accuracy of INS alignment.

Purpose of the Study:

• To propose a novel INS initial alignment method for disturbed bases using a Vondrak low-pass filter.
• To analyze and compare the characteristic errors of INS force observations on stationary versus disturbed bases.
• To enhance the attitude accuracy of INS by reducing noise in force observations.

Main Methods:

• Introduced principles of coarse and fine initial alignment for INS.
• Performed spectral analysis to understand noise characteristics in force observations.
• Developed a Vondrak low-pass filter, optimized with genetic algorithms, for noise reduction.
• Validated the proposed alignment method through simulated and actual experiments.

Main Results:

• The Vondrak filter effectively eliminated high-frequency noise from force observations.
• The proposed alignment method significantly improved attitude accuracy compared to conventional methods.
• The new method requires setting only one parameter, simplifying implementation.

Conclusions:

• The novel alignment method with the Vondrak filter offers improved performance for INS in disturbed environments.
• The Vondrak filter provides a more accurate and easier way to reduce noise in force observations.
• The proposed technique enhances the practicality and accuracy of INS initial alignment.