Keric Hill (PDS/IAI)
Keywords: astrodynamics, UCT, tracklets, RSO
Abstract:
A method is proposed for detecting and estimating maneuvers using optical (angles-only) tracklets. After the correlator recognizes that a Resident Space Object (RSO) has maneuvered and no longer matches its pre-maneuver trajectory, observations for that RSO will be classified as Uncorrelated Tracks (UCTs). Using an algorithm to indicate when known RSOs have gone missing, an initial estimate for a maneuver can be obtained by processing the pool of UCTs with an algorithm called Two Angle Pairs Initial Orbit with Conjunction Analysis (TAPIOCA). TAPIOCA computes hypothesized orbits on the admissible region for two angles-only observations and back-propagates the orbits to look for conjunctions with the last known trajectories for the missing RSOs. If a conjunction is found with a small miss distance and velocity difference, it is used as an estimate for a maneuver. Once an initial estimate for the maneuver is obtained from TAPIOCA, a batch least-squares process is outlined which can refine that maneuver estimate and provide predictions for the trajectory and covariance after the maneuver such that the correlator will correctly identify that object for subsequent tracklets. As more tracklets become available after the maneuver, it is continually refined in the least-squares estimator. The maneuver estimates include start time and thrust. Maneuver detection results are shown for both simulated and real geostationary objects. Using Raven observations of Galaxy 15, the method was able to find five maneuvers over four weeks which were verified against precise WAAS ephemeris.
Date of Conference: September 9-12, 2014
Track: Astrodynamics