Precision navigation of miniaturized distributed space systems using GNSS
Abstract/Contents
- Abstract
- The way humans conduct spaceflight is being revolutionized by two key trends. The first trend is the distribution of payload tasks among multiple coordinated units, referred to as Distributed Space Systems (DSS), which allow for advances in planetary science, astronomy and astrophysics, and space infrastructure and development. The second is spacecraft miniaturization, where micro- and nanosatellites are transitioning from being merely educational tools to a viable scientific platform. Together, these pushes call for strict Guidance, Navigation, and Control (GNC) requirements while adhering to on-board constraints. In particular, advanced DSS require precise real-time knowledge of the relative orbits of each spacecraft in the system. Centimeter-level relative positioning precision can be obtained from Global Navigation Satellite Systems (GNSS), but this has only been demonstrated on ground through post-processing and only between two spacecraft. This research presents a methodology for nanosatellite swarms to provide on-board navigation solutions in real time using differential GNSS, combining the precision from ground-operated navigation systems with the timeliness of on-board payloads. To accomplish this task, a large swarm is divided into smaller subsets, within which differential GNSS provides centimeter-level relative positioning through successful carrier-phase integer ambiguity resolution. These precise subset estimates are then fused together to form a full swarm orbit estimate on each spacecraft. This system is validated in a new GNSS testbed at Stanford, designed to characterize and profile both hardware and software for GNC payloads. A hardware-in-the-loop experiment demonstrates that the new navigation system can provide precise navigation solutions to a swarm of six spacecraft, including the first demonstration of integer ambiguity resolution on CubeSat avionics. The payload is then applied to two upcoming science missions for which it is considered a mission-enabling technology: the Virtual Super-resolution Optics with Reconfigurable Swarms (VISORS) and the Miniaturized Distributed Occulter/Telescope (mDOT). These missions both present unique challenges, showing that the navigation system can meet strict mission requirements in the presence of frequent control maneuvers and large inter-spacecraft separations. In the latter case, a novel hybrid extended/unscented Kalman filter (KF) estimates the differential ionospheric path delay between GNSS receivers in the swarm, using an unscented KF measurement update to better handle nonlinearities while reducing computational load through an extended KF time update.
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 | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Giralo, Vincent Paul |
|---|---|
| Degree supervisor | D'Amico, Simone |
| Thesis advisor | D'Amico, Simone |
| Thesis advisor | Gao, Grace X. (Grace Xingxin) |
| Thesis advisor | Schwager, Mac |
| Degree committee member | Gao, Grace X. (Grace Xingxin) |
| Degree committee member | Schwager, Mac |
| Associated with | Stanford University, Department of Aeronautics and Astronautics |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Vincent Paul Giralo. |
|---|---|
| Note | Submitted to the Department of Aeronautics and Astronautics. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/dp334dn5706 |
Access conditions
- Copyright
- © 2021 by Vincent Paul Giralo
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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