Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references (p. 179-182). / In this thesis, I present neutral atmosphere, ionosphere and total delays experienced by GPS signals traveling to space vehicles during launch, orbit and reentry. I calculate these delays for receivers at 0 km to 1700 km altitude by ray-tracing through the Global Reference Atmosphere Model (1999) and the International Reference Ionosphere (2001). These delays are potentially much larger than those experienced by signals traveling to GPS receivers near the surface of the Earth, but are primarily experienced at negative elevation angles, and are therefore most relevant for space vehicles with limited visibility of GPS satellites and during launch and reentry. I compare these signal delays to the delays predicted by three onboard delay models: the Altshuler and NATO neutral atmosphere delay models, and the Klobuchar ionosphere delay model. I find that these models are inadequate when the space vehicle is in orbit. The NATO model will suffice during the final period of reentry, where it predicts the neutral atmosphere delay to within 1 m of the ray-traced value, but it will not suffice when a satellite is rising or setting. I propose a method to extend the NATO model for receivers at higher altitudes. The Klobuchar model will suffice for most satellites during reentry, but will potentially predict ionosphere delays with errors up to 30 m, and will not suffice when a satellite is rising or setting. / by Rachel Neville Thessin. / S.M.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/33211 |
| Date | January 2005 |
| Creators | Thessin, Rachel Neville |
| Contributors | Anthony J. Bogner and Thomas A. Herring., Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics., Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 182 p., 5799235 bytes, 5819780 bytes, application/pdf, application/pdf, application/pdf |
| Rights | M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582 |
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