Initial Alignment of Large Azimuth Misalignment Angles in SINS Based on Adaptive UPF

Area of Science:

• Navigation Systems
• Signal Processing
• Control Theory

Background:

• Strapdown inertial navigation systems (SINS) require accurate initial alignment.
• Large azimuth misalignment angles pose challenges for traditional SINS alignment methods.
• Unscented Particle Filters (UPF) are used for non-linear filtering in SINS.

Purpose of the Study:

• To analyze SINS initial alignment with large azimuth misalignment angles.
• To propose and evaluate an adaptive UPF for improved SINS initial alignment.
• To overcome limitations of standard UPF, such as particle degradation.

Main Methods:

• Developed an adaptive UPF incorporating a strong tracking filter concept.
• Introduced an attenuation memory factor to enhance residual error correction.
• Compared the adaptive UPF with a standard UPF using simulations and turntable experiments.

Main Results:

• The adaptive UPF effectively overcomes particle degradation issues.
• Improved correction of current information residual error.
• Enhanced system performance by reducing the influence of system simplification and noise uncertainty.

Conclusions:

• The adaptive UPF demonstrates improved speed and precision for SINS initial alignment with large azimuth misalignment angles.
• The proposed method is effective regardless of whether system noise statistical properties are certain or uncertain.
• Simulation and experimental results validate the enhanced performance of the adaptive UPF.