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Orbital maneuver detection for non-cooperative targets in space is a key task in space situational awareness. This study develops a passive maneuver detection algorithm using line-of-sight angles measured by a space-based optical sensor, especially for targets in high-altitude orbit. Emphasis is placed on constructing a new characterization for maneuvers as well as the corresponding detection method. First, the concept of relative angular momentum is introduced to characterize the orbital maneuver of the target quantitatively, and the sensitivity of the proposed characterization is analyzed mathematically. Second, a maneuver detection algorithm based on the new characterization is designed in which sliding windows and correlations are utilized to determine the mutation of the maneuver characterization. Subsequently, a numerical simulation system composed of error models, reference missions and trajectories, and computation models for estimating errors is established. Then, the proposed algorithm is verified through numerical simulations for both long-range and close-range targets. The results indicate that the proposed algorithm is effective. Additionally, the sensitivity of the proposed algorithm to the width of the sliding window, accuracy of the optical sensor, magnitude and number of maneuvers, and different relative orbit types is analyzed, and the sensitivity of the new characterization is verified using simulations. [ABSTRACT FROM AUTHOR]

This research studies the angles-only relative navigation problem for spacecraft proximity operations when the camera offset from the vehicle center-of-mass allows for range observability. Emphasis is placed on developing an analytic observability criterion for the camera offset within the context of the Clohessy-Wiltshire (CW) dynamics and evaluating the performance of the navigation algorithm in nonlinear dynamics environment. Further, the newly observability criterion is mathematically derived by changing the analyzing problem of the nonlinear observability into the solving problem of linear equations, and the criterion can be a powerful guideline to be followed to install the camera and execute attitude maneuvers. Moreover, navigation filtering algorithm based on an Unscented Kalman Filter and systematic nonlinear Monte Carlo simulation framework are established to verify the analytic observability criterion and evaluate the performance of the proposed algorithm through typical proximity missions. The sensitivity of the navigation accuracy to spacecraft trajectories and camera offset is presented and discussed. The conclusion is that the camera offset is required to have out-of-plane component and cannot be parallel to the line-of-sight vector in order to supply range observability. [ABSTRACT FROM AUTHOR]