Description of field of research:

The increasing amount of space debris poses significant threats to space assets. To avoid collisions with space debris, the acquisition of highly accurate and reliable orbital information of these threatening objects is necessary. A main caveat of optical observations (i.e., angles and angular rates) for space tracking is that the distance between the space object and the ground station is unknown. This factor can result in significant errors in obtaining the full information of the orbital state. Additionally, for many real space debris tracking campaigns, limited observation times and short visible arcs lead to sparse observational data for a specific space object, which present more non-Gaussianity to the initial orbit determination (IOD) problem. If there are large gaps between any two consecutive tracking arcs, the imperfect orbital dynamics with uncertain orbital parameters (e.g., area to mass ratio for atmospheric drag and solar radiation pressure) degrades the prediction accuracy and contributes to filter divergence. This project aims to solve for this nonlinear and non-Gaussian IOD problem by leveraging a high-order unscented estimator which accounts for effects due to third- and fourth-order moments in addition to the mean and covariance. This method is compared to Gaussian-mixture unscented Kalman filter via both simulated and real-world optical tracking observations.


Mechanical and Manufacturing Engineering

Research areas

Estimation, orbital mechanics

Existing code for optical observation processing, admissible region and estimators for initial orbit determination will be provided. The candidate needs to integrate the codes together and generate results.

Initial orbit determination code and report.

Zvonimir Stojanovski and Dmitry Savransky, Higher-Order Unscented Estimator, Journal of Guidance, Control, and Dynamics 2021 44:12, 2186-2198

Yang Yang and Han Cai, Analysis Of Adaptive Gaussian Mixture Unscented Kalman Filter Using Sparse Optical Observations For Initial Orbit Determination, Proceedings of 68th International Astronautical Conference (2017)