Date of Award

Spring 1-1-2019

Document Type


Degree Name

Master of Science (MS)


Aerospace Engineering Sciences

First Advisor

Dennis M. Akos

Second Advisor

Nagaraj C. Shivaramaiah

Third Advisor

Nisar R. Ahmed


Throughout the course of this research the validity and effectiveness of using automatic gain control measurements as a means of interference detection is explored. Global Navigation Satellite Systems are a crucial part of the global infrastructure and thus it is paramount that the signal coming from these systems is available to all users at all times. The original proclamation arises from the need to create methods of detection that are universally applicable to the vast spectrum of commercial off-the-shelf GNSS receivers in use today. Current forms of detection are found to be inadequate as they require additional hardware or extensive requirements in computation power. AGC is purposed as an alternative, therefore this paper first proves that there exists an inverse proportionality relationship between the AGC metric and the power level of the received signal. This is done through extensive experimentation of the AGC response characteristics of three COTS receivers with respect to varying types of input. With the relationship proven the paper then provides a set of GPS L1 RFI detection applications which take advantage of these findings. Finally, conclusions on the effectiveness of AGC and future applications are provided.