Date of Award


Document Type


Degree Name

Master of Science (MS)


Electrical and Computer Engineering (Holcomb Dept. of)

Committee Member

Yongqiang Wang

Committee Member

Richard Brooks

Committee Member

Harlan Russel

Committee Member

Kuang-Ching Wang


The Global Positioning System (GPS) is used ubiquitously for navigation and timing synchronization purposes. Many telecommunication, finance and aviation systems rely heavily on GPS information for routine operations. GPS functions by relying on satellites orbiting the earth in very accurately predictable orbits, which are used as references to identify the positions of objects (receivers). Receivers calculate their positions by receiving GPS signals and calculating their relative distances to each of the satellites. With enough relative distances, the receiver can resolve its position using the method known as trilateration [1]. In this thesis, we underline the vulnerability of this orbiting infrastructure to spoofing attacks, by easily procurable and affordable software defined radios. GPS Signal spoofing is a type of malicious attack, where an attacker generates fake GPS signal with valid GPS properties but false navigational and/or timing information to fool non-suspecting receivers. These signals appear authentic and receivers end up processing the false signal and extracting wrong information. There are two types of GPS services, civilian and military. The military service is encrypted and not vulnerable to such attacks because the pseudorandom codes are not disclosed to the public. However, this service is accessible to authorized military personnel alone. All other commercial and public GPS receivers which form the mass of the population are vulnerable to spoofing attacks. The civilian GPS broadcast band is not encrypted, and this makes it easy for an attacker to recreate the signal that appears valid to GPS receivers. In this thesis we implement a low cost, easy for mass-market application Doppler measurement based spoofing detection approach, utilizing non-specialized off the shelf commercial receivers.



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