This thesis presents a dedicated GPS-denied landing system designed for electric vertical takeoff and landing (eVTOL) aircraft. The system employs active fiducial light pattern localization (AFLPL), which provides highly accurate and reliable navigation during critical landing phases. AFLPL utilizes images of a constellation comprised of modulating infrared lights strategically positioned on the landing site, to determine the aircraft pose through the use of a perspective-n-point (PnP) solver. The AFLPL system underwent thorough development, enhancement, and implementation to address and demonstrate its potential in navigation and its inherent limitations. A proposed method addresses the limitations of AFLPL by using an extended Kalman filter (EKF) to fuse PnP camera pose estimates with sensor measurements from an inertial measurement unit (IMU), attitude heading reference system (AHRS), and optional global positioning system (GPS). The EKF estimation is reported to significantly enhance the accuracy, reliability, and update frequency of the aircraft state estimation. To refine and validate the AFLPL and EKF algorithms, a simulation was developed, consisting of an eVTOL executing a glideslope landing trajectory. Furthermore, a hardware system consisting of a multirotor and infrared light ground units was implemented to test these methods under real-world conditions. This research culminated in the successful demonstration of the AFLPL-based estimation system's efficacy through an autonomous, GPS-denied landing flight test, affirming its potential to improve the navigation and control of eVTOL aircraft lacking access to GPS information.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-11340 |
| Date | 16 April 2024 |
| Creators | Brown, Aaron C. |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | https://lib.byu.edu/about/copyright/ |
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