Date of Award
School of Engineering
Dr. Bruce E. Dunne
Dr. Jeffrey Ward
Dr. Paul Keenlance
Radio Direction Finding (RDF) is commonly used for low cost tracking and navigation systems. However, for a low cost application and mobility, the design constraints are highly limited. Pseudo Doppler (PD) can improve RDF capabilities without being cost prohibitive. This work entails the analysis of PD RDF and its potential use for Unmanned Aerial Vehicles (UAV) that are currently employed in wildlife research animal tracking. PD is based on the doppler effect or doppler shift. The doppler effect works like a frequency modulator that increases or decreases the observed frequency depending on whether a signal source is approaching or receding the detector. Noting this doppler shift can be used to improve the accuracy of the RDF algorithm. Normally, deploying the doppler method would require the physical rotation of an antenna at a relatively high frequency. Instead, PD employs a grid of electrically isolated antennas and then digitally samples each of the antennas in a sequential order, mimicking the action of mechanical rotation. Thus, PD removes the requirement to physically rotate the antenna yet provides the increased accuracy available with sensing the doppler effect.
PD can be implemented at low cost using an off-the-shelf Software Defined Radio (SDR) and simple monopole antennas. This work includes the design and implementation of a PD RDF on an SDR for deployment on an existing UAV platform. The expected improved performance of the PD system is to be tested on the existing UAV platform and compared against traditional tracking methods (such as a single Yagi antenna).
Karki, Anup, "Radio direction finding using pseudo-Doppler for UAV-based Animal Tracking" (2019). Masters Theses. 968.