Toward the next generation of GPS signals : new codes and navigation security
Abstract/Contents
- Abstract
- Today, billions of users rely on GPS on a daily basis. Woven into the fabric of modern civilization, GPS underlies nearly every aspect of society's functions, including our transportation, agriculture, financial transactions, energy grid, and communication systems. Yet, despite the critical importance of GPS, its civilian signals currently (1) are open and unencrypted, meaning that an attacker can generate counterfeit GPS signals and spoof a user's position or timing solution, and (2) use codes which were designed before the recent advancements in computing. However, in 2024, the NTS-3 satellite will be launched to test new signal capabilities for the future generations of GPS, including a new digital watermark called Chimera to periodically authenticate one's received GPS signal. Furthermore, starting launches in 2026, the GPS IIIF satellites will be the first to have a fully-digital, reprogrammable payload, allowing for new opportunities to re-explore the design of the GPS signal, including their underlying codes. In this dissertation, we seek to leverage these upcoming opportunities in order to advance the next-generation signal capabilities. In particular, we develop strategies to utilize Chimera and additional self-contained sensors onboard a vehicle, such as an inertial measurement unit or wheel encoder, in order to perform continuous spoofing detection and secure, attack-resilient navigation. For our continuous spoofing detector, we use stochastic reachability analysis to conservatively model the error distributions from the self-contained sensor and GPS measurements, in order to provably satisfy a user-defined false alarm guarantee. To perform continuous, attack-resilient navigation, we further leverage the self-contained sensors and Chimera to determine how much to rely on the received GPS measurements, in order to strategically improve real-time navigation performance while mitigating any induced errors during an experienced attack. With the forthcoming ability to reprogram the GPS signals, this dissertation further proposes a new framework to design the GPS codes, leveraging stochastic optimization methods as well as present-day computational tools. To design the GPS codes within the discrete, exponentially large space of binary code sets, we utilize a natural evolution strategy to optimize a smooth probability distribution over the code space, allowing us to evaluate a gradient estimate and leverage state-of-the-art first-order optimization algorithms for code design. We demonstrate that the framework proposed in this dissertation designs codes which have lower self- and inter-signal interference, through reduced mean-squared correlation sidelobes, than competitive sets of Gold and Weil codes, which are code families used by GPS today.
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 | 2023; ©2023 |
| Publication date | 2023; 2023 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Mina, Tara Yasmin |
|---|---|
| Degree supervisor | Gao, Grace X. (Grace Xingxin) |
| Thesis advisor | Gao, Grace X. (Grace Xingxin) |
| Thesis advisor | Van Roy, Benjamin |
| Thesis advisor | Zebker, Howard |
| Degree committee member | Van Roy, Benjamin |
| Degree committee member | Zebker, Howard |
| Associated with | Stanford University, School of Engineering |
| Associated with | Stanford University, Department of Electrical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Tara Mina. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2023. |
| Location | https://purl.stanford.edu/gs043tj6001 |
Access conditions
- Copyright
- © 2023 by Tara Yasmin Mina
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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