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November 15, 2021: "More-Capable SmallSats: Autonomous Orbit Determination from Incident Light Intensity"

  • November 15, 2021
  • 4:00 p.m.
  • Dr. Riley M. Fitzgerald, Assistant Professor, Virginia Tech
  • Faculty Host: Gregory Young

Abstract: Satellites need to know where they are to execute their missions, and as small spacecraft become increasingly capable and ubiquitous it only becomes more important to reduce their reliance on external resources for this information. This seminar will first highlight some of Dr. Fitzgerald’s work on smallsat missions and operation, and will then focus on one particular topic: a method for onboard orbit determination using only measurements of sunlight intensity.

Autonomous orbit determination techniques requiring minimal hardware, computational power, and external reference are desirable for resource-constrained spacecraft, operation in GNSS-denied environments, or simply as a backup. This seminar will introduce a method for orbit identification and estimation using only time-series measurements of scalar sunlight intensity, data which should be available to most spacecraft without the need for additional hardware. By timing the duration and transients of eclipse, one may maintain a provided orbital estimate or develop a new estimate from scratch. These methods are tested against public two-line element sets and are shown to provide position estimates with an orbit-averaged error typically on the order of several kilometers in a variety of low-Earth-orbit geometries.

Bio: Dr. Riley M. Fitzgerald joined the Kevin T. Crofton Department of Aerospace and Ocean Engineering at Virginia Tech as an assistant professor in August 2021 after completing his Ph.D. in Space Systems at the Massachusetts Institute of Technology, where he studied as a fellow with the Charles Stark Draper Laboratory, Inc. since 2016; he previously completed his S.M. in Aeronautics and Astronautics at MIT, and his B.S.E. in Mechanical and Aerospace Engineering at Princeton University. Dr. Fitzgerald’s research interests lie in the interactions between space systems engineering, astrodynamics, and GN&C (guidance, navigation, and control). He focuses on areas where optimized operations and estimation techniques can address novel challenges in the space domain, for example enabling the cost-effective utilization of multi-body trajectories and increasing the capability of small satellites.