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Full-Text Articles in Engineering
Navigational Feasibility Of Flyby / Impact Missions To Interstellar Objects, Declan Moore Mages
Navigational Feasibility Of Flyby / Impact Missions To Interstellar Objects, Declan Moore Mages
Master's Theses
In October 2017, the first interstellar object, designated 1I/2017 U1 and more commonly referred to as Oumuamua, was detected passing through our solar system by the Pan-STARRS telescope, followed recently by the detection of 2I/Borisov in August 2019. These detections came much sooner than thought possible, and have redefined our understanding of the population of interstellar objects. With the construction of the next generation of powerful observatories, future detections are estimated to occur as frequently as two per year, and while there is significant scientific understanding to be gained from observing these objects remotely, a spacecraft sent to intercept one …
Enabling Autonomous Operation Of Micro Aerial Vehicles Through Gps To Gps-Denied Transitions, James Scott Jackson
Enabling Autonomous Operation Of Micro Aerial Vehicles Through Gps To Gps-Denied Transitions, James Scott Jackson
Theses and Dissertations
Micro aerial vehicles and other autonomous systems have the potential to truly transform life as we know it, however much of the potential of autonomous systems remains unrealized because reliable navigation is still an unsolved problem with significant challenges. This dissertation presents solutions to many aspects of autonomous navigation. First, it presents ROSflight, a software and hardware architure that allows for rapid prototyping and experimentation of autonomy algorithms on MAVs with lightweight, efficient flight control. Next, this dissertation presents improvments to the state-of-the-art in optimal control of quadrotors by utilizing the error-state formulation frequently utilized in state estimation. It is …
Cooperative Navigation Of Fixed-Wing Micro Air Vehicles In Gps-Denied Environments, Gary James Ellingson
Cooperative Navigation Of Fixed-Wing Micro Air Vehicles In Gps-Denied Environments, Gary James Ellingson
Theses and Dissertations
Micro air vehicles have recently gained popularity due to their potential as autonomous systems. Their future impact, however, will depend in part on how well they can navigate in GPS-denied and GPS-degraded environments. In response to this need, this dissertation investigates a potential solution for GPS-denied operations called relative navigation. The method utilizes keyframe-to-keyframe odometry estimates and their covariances in a global back end that represents the global state as a pose graph. The back end is able to effectively represent nonlinear uncertainties and incorporate opportunistic global constraints. The GPS-denied research community has, for the most part, neglected to consider …
Collaborative Uav Planning, Mapping, And Exploration In Gps-Denied Environments, Jacob Moroni Olson
Collaborative Uav Planning, Mapping, And Exploration In Gps-Denied Environments, Jacob Moroni Olson
Theses and Dissertations
The use of multirotor UAVs to map GPS-degraded environments is useful for many purposes ranging from routine structural inspections to post-disaster exploration to search for survivors and evaluate structural integrity. Multirotor UAVs are able to reach many areas that humans and other robots cannot safely access. Because of their relatively short operational flight time compared to other robotic applications, using multiple UAVs to collaboratively map these environments can streamline the mapping process significantly. This research focuses on four primary areas regarding autonomous mapping and navigation with multiple UAVs in complex unknown or partially unknown GPS-denied environments: The first area is …
Spacecraft Trajectory Planning For Optimal Observability Using Angles-Only Navigation, Francisco José Franquiz
Spacecraft Trajectory Planning For Optimal Observability Using Angles-Only Navigation, Francisco José Franquiz
Doctoral Dissertations and Master's Theses
This work leverages existing techniques in angles-only navigation to develop optimal range observability maneuvers and trajectory planning methods for spacecraft under constrained relative motion. The resulting contribution is a guidance method for impulsive rendezvous and proximity operations valid for elliptic orbits of arbitrary eccentricity.
The system dynamics describe the relative motion of an arbitrary number of maneuvering (chaser) spacecraft about a single non-cooperative resident-space-object (RSO). The chaser spacecraft motion is constrained in terms of the 1) collision bounds of the RSO, 2) maximum fuel usage, 3) eclipse avoidance, and 4) optical sensor field of view restrictions. When more than one …
Robot Navigation In Cluttered Environments With Deep Reinforcement Learning, Ryan Weideman
Robot Navigation In Cluttered Environments With Deep Reinforcement Learning, Ryan Weideman
Master's Theses
The application of robotics in cluttered and dynamic environments provides a wealth of challenges. This thesis proposes a deep reinforcement learning based system that determines collision free navigation robot velocities directly from a sequence of depth images and a desired direction of travel. The system is designed such that a real robot could be placed in an unmapped, cluttered environment and be able to navigate in a desired direction with no prior knowledge. Deep Q-learning, coupled with the innovations of double Q-learning and dueling Q-networks, is applied. Two modifications of this architecture are presented to incorporate direction heading information that …
A Swimming Open-Water Navigation Assistive Headset And Receiver, Zakk B. Rhodes
A Swimming Open-Water Navigation Assistive Headset And Receiver, Zakk B. Rhodes
All Graduate Plan B and other Reports, Spring 1920 to Spring 2023
Open water swimming is a common activity dating back to ancient times. One challenge with open water swimming is navigation because while maintaining proper swimming technique suggests the head be in the water, it is difficult to see where one is going. Thus swimmers must bring their head out of the water periodically to sight landmarks. This work describes a solution to this problem by a design for a GPS device to assist swimmers with navigation. The swimmer can plan their own route, send it to the device, and then be guided by the device. They then will not have …
Algorithm For Geodetic Positioning Based On Angle-Of-Arrival Of Automatic Dependent Surveillance-Broadcasts, Richard Allen Gross
Algorithm For Geodetic Positioning Based On Angle-Of-Arrival Of Automatic Dependent Surveillance-Broadcasts, Richard Allen Gross
Masters Theses
This paper develops a non-precision, three-dimensional, geodetic positioning algorithm for airborne vehicles. The algorithm leverages the proliferation of Automatic Dependent Surveillance – Broadcast (ADS-B) equipped aircraft, utilizing them as airborne navigation aids to generate an RF Angle-of-Arrival (AOA) and Angle-of-Elevation (AOE) based geodetic position. The resulting geodetic position can serve as a redundant navigation system for use during locally limited Global Navigation Satellite System (GNSS) availability, be used to validate on-board satellite navigation systems in an effort to detect local spoofing attempts, and be used to validate ADS-B position reports.
The navigation algorithm is an implementation of an Extended Kalman …
Magnetic Field Aided Indoor Navigation, William F. Storms
Magnetic Field Aided Indoor Navigation, William F. Storms
Theses and Dissertations
This research effort examines inertial navigation system aiding using magnetic field intensity data and a Kalman filter in an indoor environment. Many current aiding methods do not work well in an indoor environment, like aiding using the Global Positioning System. The method presented in this research uses magnetic field intensity data from a three-axis magnetometer in order to estimate position using a maximum – likelihood approach. The position measurements are then combined with a motion model using a Kalman filter. The magnetic field navigation algorithm is tested using a combination of simulated and real measurements. These tests are conducted using …