A Novel Coarse Alignment Method for SINS Using Special Orthogonal Group Optimal Estimation.

Area of Science:

• Navigation Systems Engineering
• Control Theory
• Applied Mathematics

Background:

• Strapdown inertial navigation systems (SINS) face alignment challenges on dynamic platforms.
• Traditional alignment methods often suffer from issues like non-convexity and reliance on specific observational data.

Purpose of the Study:

• To propose a novel coarse alignment method for SINS on swing bases.
• To address the limitations of existing alignment techniques by leveraging Lie group theory and optimal estimation.

Main Methods:

• Directly updating the rotation matrix using error Lie algebra derived from Lie group differential equations.
• Developing an optimal estimation method employing exact error Lie algebra as an innovation term.
• Proving the asymptotic convergence of the proposed method using Lyapunov's second law.

Main Results:

• The proposed method avoids the non-convexity issues inherent in traditional approaches.
• It eliminates the requirement for non-collinear vector observations.
• Simulation and experimental results confirm superior performance in alignment accuracy and time compared to existing methods.

Conclusions:

• The novel coarse alignment method effectively achieves self-alignment of SINS on swing bases.
• The technique offers enhanced accuracy and reduced alignment time.
• This Lie group-based optimal estimation provides a robust solution for SINS alignment on dynamic platforms.