Receiver-Side Physics-Informed Residual Digital Twin for Predictive Fine Tracking in Inter-Satellite Optical Links

This paper presents a receiver-side physics-informed residual digital twin (PIR-Twin) for fine tracking in inter-satellite optical links. The method combines nominal line-of-sight transition physics, Gaussian optics modeling, nonlinear quadrant-photodetector observation, and extended Kalman filter synchronization. A normalized autoregressive ridge model is employed to learn the transition mismatch between nominal and actual dynamics, enabling predictive compensation of residual motion despite sensor noise, vibration, and actuator latency.