Orbital diversity for global navigation satellite systems [electronic resource]
- Tyler Gerald René Reid.
- Physical description
- 1 online resource.
- Reid, Tyler Gerald René.
- Enge, Per, primary advisor.
- Kochenderfer, Mykel J., 1980- advisor.
- Walter, Todd, advisor.
- Stanford University. Department of Aeronautics and Astronautics.
- The underlying theme of this dissertation is the utilization of new orbits to improve the Global Navigation Satellite System (GNSS) we rely upon in nearly all facets of modern life. This includes new orbits for safety-critical augmentation systems as well as for navigation core-constellations. Today, safety-oriented augmentation is placed in geosynchronous orbit while navigation core-constellations such as GPS are placed in medium Earth orbit. This lack of diversity leads to certain pitfalls. Augmentation systems are limited in platforms on which they can piggyback and do not reach users at high latitude. Navigation systems have limited geometric diversity as well as faint signals, leaving them vulnerable to interference and limited in urban and indoor environments. The orbital diversity introduced here improves the service, reliability, and functionality of GNSS. In the present work, new orbital representations are developed to enable orbits such as medium, inclined geosynchronous, and highly elliptical for augmentation with a tenfold improvement in orbit description accuracy compared to service today. This, along with constellation and frequency diversity on the horizon, is shown to enable safety-critical services for both aviation and maritime operations in the entire northern hemisphere. This is of great importance in the Arctic where commerce and traffic is on the rise due to decreasing sea ice. The addition of these orbit classes also increases SBAS visibility in urban canyons where safety critical systems like autonomous automobiles are beginning operation. For navigation, we propose leveraging the wealth of low Earth orbiting (LEO) satellites coming in the near future. This unprecedented space infrastructure is planned by the likes of OneWeb, SpaceX, and Boeing to deliver broadband Internet globally. These LEO constellations offer a threefold improvement on geometry compared to navigation constellations today, relaxing constraints on other aspects while still maintaining the positioning performance of GPS. Closer to Earth, LEO offers less path loss than MEO, improving signal strength by 1000 fold (30 dB). This strengthens us to interference and aids substantially in urban and indoor environments.
- Publication date
- Submitted to the Department of Aeronautics and Astronautics.
- Thesis (Ph.D.)--Stanford University, 2017.