Orbital Mechanics and Sensor Fusion in Space Domain Awareness
Space Domain Awareness (SDA) is the technical study and tracking of objects in Earth's orbit, including active satellites and debris. It is the aerospace equivalent of air traffic control but at orbital velocities ($7–8$ km/s).
1. Astrodynamics and Resident Space Object (RSO) Tracking
SDA systems use a network of ground-based radars and optical telescopes to maintain a "Catalog of Objects." The core task is Orbit Determination, where multiple observations are used to calculate the six classical orbital elements (e.g., inclination, eccentricity, semi-major axis).
2. Conjunction Assessment and Collision Avoidance
When two RSOs are projected to pass within a certain "Miss Distance," the system performs a Conjunction Assessment. This involves calculating the Probability of Collision ($P_c$) using covariance matrices that account for the uncertainty in the position and velocity of both objects.
3. Multi-Source Sensor Fusion
SDA platforms must fuse data from disparate sources: narrow-beam radars (for precise ranging), wide-field telescopes (for search), and space-based sensors. This requires Kalman Filtering algorithms to synchronize timestamps and reference frames, providing a unified "Common Operating Picture" of the orbital environment