Engineering Commons^™

Gps Denied Localization Using Ultra-Wideband Radios, Joshua P. Vanfleet

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

GPS denied environments cause each unmanned ground vehicle (UGV) in an autonomous convoy to lose positional accuracy which can lead to inoperability, or even damage. In order for autonomous convoy systems to fill the needs of any particular field, a well-performing system must be designed such that a convoy can operate in any environment. Ultra-wideband (UWB) radios are a proposed solution to GPS denied localization. The main objective of this research is to use UWB radios to localize a leader vehicle within a convoy situation while in a GPS denied environment.

A Comparative Study Of Feature Detection Methods For Auv Localization, Andrew Y. Kim

Master's Theses

Underwater localization is a difficult task when it comes to making the system autonomous due to the unpredictable environment. The fact that radio signals such as GPS cannot be transmitted through water makes autonomous movement and localization underwater even more challenging. One specific method that is widely used for autonomous underwater navigation applications is Simultaneous Localization and Mapping (SLAM), a technique in which a map is created and updated while localizing the vehicle within the map. In SLAM, feature detection is used in landmark extraction and data association by examining each pixel and differentiating landmarks pixels from those of the …

Design, Analysis And Optimization Of Visible Light Communications Based Indoor Access Systems For Mobile And Internet Of Things Applications, Sihua Shao

Dissertations

Demands for indoor broadband wireless access services are expected to outstrip the spectrum capacity in the near-term "spectrum crunch". Deploying additional femtocells to address "spectrum crunch" is cost-inefficient due to the "backhaul challenge" and the exorbitant system maintenance. According to an Alcatel-Lucent report, most mobile Internet access traffic happens indoors. To alleviate the "spectrum crunch" and the "backhaul challenge" problems, visible light communication (VLC) emerges as an attractive candidate for indoor wireless access in the 5G architecture. In particular, VLC utilizes LED or fluorescent lamps to send out imperceptible flickering light that can be captured by a smart phone camera …

Rss-Based Device-Free Passive Detection And Localization Using Home Automation Network Radio Frequencies, Tiffany M. Phan

Theses and Dissertations

This research provided a proof of concept for a device-free passive (DfP) system capable of detecting and localizing a target through exploitation of a home automation network’s radio frequency (RF) signals. The system was developed using Insteon devices with a 915 MHz center frequency. Without developer privileges, limitations of the Insteon technology like no intrinsic received signal strength (RSS) field and silent periods between messages were overcome by using software-defined radios to simulate Insteon devices capable of collecting and reporting RSS, and by creating a message generation script and implementing a calibrated filter threshold to reduce silent periods. Evaluation of …

Collaborative Appearance-Based Place Recognition And Improving Place Recognition Using Detection Of Dynamic Objects, Juan Pablo Munoz

Dissertations, Theses, and Capstone Projects

This dissertation makes contributions to the problem of Long-Term Appearance-Based Place Recognition. We present a framework for place recognition in a collaborative scheme and a method to reduce the impact of dynamic objects on place representations. We demonstrate our findings using a state-of-the-art place recognition approach.

We begin in Part I by describing the general problem of place recognition and its importance in applications where accurate localization is crucial. We discuss feature detection and description and also explain the functioning of several place recognition frameworks.

In Part II, we present a novel framework for collaboration between agents from a pure …

Leveraging 3d Models For Sar-Based Navigation In Gps-Denied Environments, Zachary A. Reid

Browse all Theses and Dissertations

This thesis considers the use of synthetic aperture radar (SAR) to provide absolute platform position information in scenarios where GPS signals may be degraded, jammed, or spoofed. Two algorithms are presented, and both leverage known 3D ground structure in an area of interest, e.g. provided by LIDAR data, to provide georeferenced position information to airborne SAR platforms. The first approach is based on the wide-aperture layover properties of elevated reflectors, while the second approach is based on correlating backprojected imagery with digital elevation imagery. Both of these approaches constitute the system we have designated: SARNAV. Building on 3D backprojection, localization …