Date of Award


Document Type


Degree Name

Master of Science in Electrical Engineering


Department of Electrical and Computer Engineering

First Advisor

John F. Raquet, PhD


This research proposes two schemes utilizing very-low frequency (VLF) electromagnetic waves to navigate underground. The first scheme consists of using above-ground beacon transmitters to broadcast VLF signals to an underground mobile receiver which uses methods such as triangulation and trilateration to obtain a position solution. The second scheme consists of using above-ground reference receivers along with an underground mobile receiver to form time-difference- of-arrival measurements of incoming VLF signals of opportunity, such as lightning strike emissions, to calculate a position solution. The objective of this thesis is to develop positioning algorithms and use simulations as a tool to characterize the effects that varying parameters such as measurement errors, measurement type, number of measurements, transmitter/ reference receiver location, mobile receiver position, and material constant errors have on the accuracy of a position solution. The results show trends that would still be expected using more complex methods and models.

AFIT Designator


DTIC Accession Number