LEO-Based Coarse Positioning Through Angle-of-Arrival Estimation of Signals of Opportunity

This work introduces a novel coarse positioning system based on the estimation of the Angles-of-Arrival (AoAs) of Signals of Opportunity from a spacecraft in the Low Earth Orbit. The AoA estimation is done in real-time using phase interferometry through a dedicated hardware architecture. The 2D position is achieved by means of a simplified geometrical model based on the estimated angles. The experimental campaign aimed to assess the fit of the proposed model with reality, the AoA estimation accuracy, and the final positioning error. Results showed that the system can track the angular position of a fast-moving spacecraft with a precision of tenths of a degree. The final positioning accuracy demonstrates the effectiveness of the system for real-time coarse positioning.