A laser-driven fiber-optic gyroscope for inertial guidance of transoceanic flights
Abstract/Contents
- Abstract
- The performance of commercially available fiber optic gyroscopes (FOGs) is limited by their scale-factor instability and noise, which are both due to high noise and poor wavelength stability of the superfluorescent fiber source (SFS) used to interrogate the FOG's sensing coil. A promising way forward is to replace the SFS with a laser, which has a much lower noise and better wavelength stability. Historically, lasers have not been used in FOGs because their high temporal coherence introduces several dominant sources of noise and drift in the fiber coil. However, recent investigations have shown that laser-driven FOGs can have exceedingly low noise and good scale-factor stability if the coherence of the laser is suppressed by broadening the laser linewidth with external phase modulation. In this thesis, we develop a new analytical model that derives the error in an aircraft's position from a gyroscope's known noise and drift, inferred from a measured Allan deviation of the sensor's output time trace. Using this model, we derive the noise and drift required to satisfy the Federal Aviation Administration's requirements for a trans-Pacific flight. We also developed a complete model of the coherence of a laser broadened by wideband phase modulation and use this model to optimize the coherence suppression. With most of the coherent effects suppressed by an optimally modulated laser, we performed one of the most exhaustive studies on the sources of drift conducted on a laser-driven FOG. In the process, we identified four dominant sources of drift, and implemented a variety of suppression techniques to reduce them. As a result, the long-term stability of the 3-km FOG tested in this research was improved by a factor of 30 relative to the previous world-record laser-driven FOG. This FOG exhibited a noise of 0.9 mdeg/√hour and a record-breaking drift of 12.7 mdeg/hour (characterized using the Allan-deviation maximum). The measured output of this FOG was used to simulate 20 10-hour trans-Pacific flights of an aircraft guided solely by inertial sensors. 95% of the flights landed within ±10 nmi of their intended destination. To our knowledge, this is the first report of a laser-driven FOG that meets the Federal Aviation Administration's criterion for aircraft navigation.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2022; ©2022 |
| Publication date | 2022; 2022 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Wheeler, Jonathan Morgan |
|---|---|
| Degree supervisor | Digonnet, Michel J. F |
| Thesis advisor | Digonnet, Michel J. F |
| Thesis advisor | Kahn, Joseph M. (Joseph Mardell) |
| Thesis advisor | Miller, David |
| Degree committee member | Kahn, Joseph M. (Joseph Mardell) |
| Degree committee member | Miller, David |
| Associated with | Stanford University, Department of Electrical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Jonathan Morgan Wheeler. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2022. |
| Location | https://purl.stanford.edu/bv922rg0936 |
Access conditions
- Copyright
- © 2022 by Jonathan Morgan Wheeler
- License
- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
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