Date of Award
5-2018
Access Type
Thesis - Open Access
Degree Name
Master of Science in Aerospace Engineering
Department
Graduate Studies
Committee Chair
Dr. Richard Prazenica
First Committee Member
Dr. Hever Moncayo
Second Committee Member
Dr. Troy Henderson
Abstract
This thesis presents the development of vision-based state estimation algorithms to enable a quadcopter UAV to navigate and explore a previously unknown GPS denied environment. These state estimation algorithms are based on tracked Speeded-Up Robust Features (SURF) points and the homography relationship that relates the camera motion to the locations of tracked planar feature points in the image plane. An extended Kalman filter implementation is developed to perform sensor fusion using measurements from an onboard inertial measurement unit (accelerometers and rate gyros) with vision-based measurements derived from the homography relationship. Therefore, the measurement update in the filter requires the processing of images from a monocular camera to detect and track planar feature points followed by the computation of homography parameters. The state estimation algorithms are designed to be independent of GPS since GPS can be unreliable or unavailable in many operational environments of interest such as urban environments. The state estimation algorithms are implemented using simulated data from a quadcopter UAV and then tested using post processed video and IMU data from flights of an autonomous quadcopter. The homography-based state estimation algorithm was effective, but accumulates drift errors over time due to the relativistic homography measurement of position.
Scholarly Commons Citation
Armijos, Andres S. Chavez, "Homography-Based State Estimation for Autonomous Exploration in Unknown Environments" (2018). Doctoral Dissertations and Master's Theses. 396.
https://commons.erau.edu/edt/396
