Available at: https://digitalcommons.calpoly.edu/theses/3299
Date of Award
6-2026
Degree Name
MS in Aerospace Engineering
Department/Program
Aerospace Engineering
College
College of Engineering
Advisor
Kira Abercromby
Advisor Department
Aerospace Engineering
Advisor College
College of Engineering
Abstract
Low Earth orbit (LEO) is becoming increasingly congested, furthering the need for accurate tracking and catalog maintenance. Initial orbit determination (IOD) is the first step in this process, providing a preliminary estimate of an object’s state given observations. When it comes to LEO optical observations, a large portion of them are inherently short in duration. Angles-only IOD methods struggle with this data, often producing highly inaccurate solutions that limit reacquisition capabilities. This study expands on prior short arc IOD research, testing seven classical and assumed circular orbit (ACO)-modified angles-only IOD algorithms on real LEO observational data spanning 0-4 degrees of arc length and assessing solution accuracy using multiple error metrics. Following, IOD solutions are analyzed for reacquisition capabilities using two separate studies. The first compares the IOD predicted states to real secondary observations, while the second compares them to TLE states across consecutive IOD periods. Consistent with prior work, solution accuracy increases with arc length, with 0-1 degree being the regime where method choice is most critical. Ultimately, the Gooding ACO method was found to be the best overall IOD and reacquisition method for near-circular LEO objects. However, limited by its sensitivity to modest eccentricity and pass dependency driven by local versus global minimum convergence, the Gauss ACO method remains a reliable second option. Additionally, findings suggest short arc IOD solutions cannot facilitate consistent and reliable same station reacquisition, although reacquisition from an alternate ground station is feasible using Gooding ACO with 3-4 degrees of arc. In general, an observer should aim to collect as much arc as possible and use any prior information on an object’s orbit to inform method choice. If no prior information is available, the Gooding ACO and Gauss ACO methods should be used together for the best chance at object reacquisition.