Austin Gabhart
(Advisor: Prof. Dimitri Mavris)
will propose a doctoral thesis entitled,
METHODOLOGY FOR THE DESIGN OF HYBRID LUNAR PNT+C ARCHITECTURES
On
Tuesday, June 24 at 1:00 p.m. 
Collaborative Design Environment (CoDE)
Weber Space Science and Technology Building (SST II)
or
Teams (Join)
Abstract
Over the last decade, missions to the Moon have increased to historic levels for geopolitical, scientific, and economic reasons. There is no indication that this trend will not continue with all major spacefaring nations committed to a long-term habitation program. A vast array of technologies and systems will be needed to support these missions, including Position, Navigation, Timing, and Communications (PNT+C). PNT+C is understood as one of the most important needs for lunar development. To this end, several nations have put forward plans to deploy initial infrastructure. These plans focus on highly stable orbits, called frozen orbits, due to the uniquely challenging gravitational effects at the Moon. Beyond this, the design of these systems carries forward many assumptions used for the design of PNT+C systems here on Earth. The design processes used in literature are restricted and ad hoc, yielding conflicting results and influencing the evaluation of technology needs.
To address this need, a design strategy specifically tailored to the needs of the lunar PNT+C problem is put forward. Assumptions about the level of support received by orbital assets are loosened to yield an uncommon metric, User Equivalent Range Error Weighted Geometric Dilution of Precision, or KDOP. The utility of this metric will be rigorously tested to determine when it is required. Further, a novel problem formulation for satellite constellation optimization with genetic algorithms is presented. This formulation allows for the number of orbital planes to be operated on by the algorithm, efficiently searching the design space and identifying optimal designs. The synthesis of these techniques will create a design strategy that is traceable, repeatable, and accurately represents the problem. Finally, the new strategy will be demonstrated against state-of-the-art techniques to solidify its advantages.
Committee
•    Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)
•    Prof. Graeme Kennedy– School of Aerospace Engineering
•    Prof. E. Glenn Lightsey– School of Aerospace Engineering
•    Dr. Michael Steffens – Charles Stark Draper Laboratory
•    Dr. Bradford Robertson – School of Aerospace Engineering