Real-Time Estimation for Roll Angle of Spinning Projectile Based on Phase-Locked Loop on Signals from Single-Axis...

Area of Science:

• Aerospace Engineering
• Control Systems Engineering
• Geophysics

Background:

• Accurate roll angle measurement is critical for two-dimensional course correction fuze (2-D CCF) technology.
• Existing methods may be limited by amplitude dependency and geomagnetic blind areas.
• Real-time estimation of a spinning projectile's roll angle is a significant challenge.

Purpose of the Study:

• To develop a robust real-time roll angle estimation method for spinning projectiles using a single-axis magnetometer.
• To design a tracking loop system that minimizes amplitude dependency and geomagnetic blind area effects.
• To analyze measurement errors and optimize system parameters for improved accuracy.

Main Methods:

• A measurement model was established for roll angle estimation.
• A second-order frequency-locked loop (FLL)-assisted third-order phase-locked loop (PLL) was designed.
• Parameter optimization for the tracking loop was performed under varying speeds.
• Six degrees of freedom (6-DoF) trajectory simulations and rotary table experiments were conducted for validation.

Main Results:

• The designed FLL-assisted PLL system successfully obtained rolling information from magnetic signals.
• The system demonstrated reduced dependency on signal amplitude and mitigated effects from the geomagnetic blind area.
• Parameter optimization and validation through simulations and experiments confirmed accurate and stable tracking of phase and speed.
• The standard deviation (SD) of the phase error was found to be no more than 3°.

Conclusions:

• The proposed method provides an effective solution for real-time roll angle estimation in spinning projectiles.
• The FLL-assisted PLL system offers improved accuracy and stability compared to conventional methods.
• This technology is vital for enhancing the performance of two-dimensional course correction fuze (2-D CCF) systems.