Date of Award


Document Type


Degree Name

Master of Science


Department of Electrical and Computer Engineering

First Advisor

John F. Raquet, PhD


This research focuses on using the Global Positioning System (GPS) for atmospheric precipitable water (PW) estimation. Water vapor, measured in terms of PW, plays a crucial role in atmospheric processes and short-term weather forecasting. Traditional methodologies for measuring atmospheric water vapor distributions have known inadequacies, resulting in the motivation to gain good water vapor characterization via GPS. The ability to accurately forecast cloud formation and other weather phenomenon is critical, especially in the case of military operations. Using a network of GPS receivers, it is possible to estimate precipitable water throughout the network region with better accuracy than traditional methods and on a more consistent near real-time basis. First, an investigation into the effects of introducing less accurate, near real-time GPS ephemerides was accomplished. Secondly, the network geometry and data availability were degraded to simulate potential military operational constraints. Finally, several interpolation methods were applied to quantify the ability to estimate the water vapor distribution over the entire network region with limited data availability and network geometry constraints. Results showed that International GPS Service (IGS) ultra-rapid orbits introduced minimal PW estimation error (~1-2mm) while maintaining near real-time capability. The degraded perimeter network also introduced minimal PW estimation error (~1-2 mm) at the included stations, indicating potential application in constrained data environments. However, the interpolation investigation showed an overall inability to determine PW distribution over the entire network region.

AFIT Designator


DTIC Accession Number


Included in

Meteorology Commons