Vulnerability of GPS Timing Under Intentional and Unintentional Interference

  • Heba Alsaleh

Student thesis: Doctoral ThesisPhD


The vulnerability of GPS timing under intentional and unintentional interference was investigated in this research. Understanding the timing performance of GPS receivers during severe environmental conditions such as intense ionospheric scintillations, space weather events, and signal interference, was attempted through the use of specific scenario simulations. The timing accuracy of different receivers from different manufacturers was assessed under aforementioned propagation error sources. Results of this research demonstrated that the timing accuracy of the receivers is affected during simulated amplitude scintillation conditions, simulated TEC variations, and during induced jamming. However, the extent of the impact of these intentional and unintentional interference is receiver specific.The methods applied to assess the behaviour of GPS receivers during wideband (WB) and narrowband (NB) jamming provided a good prediction of receiver performance under jamming for users of GPS timing applications. The jamming experiments were conducted in a controlled laboratory environment, where the jamming signal was injected into the test receivers through a GPS constellation simulator. The carrier to noise ratio (C/No) of the received signals was a good parameter to observe the reaction of the receivers during the jamming trials. The impact of WB jamming was investigated using a matched spectrum jamming signal. Although the timing accuracy of all GPS receivers degraded as a result of this jamming, the power needed to jam GPS receivers was different for different receivers. To test the impact of NB interference, a Continuous Wave (CW) jamming signal was applied to the simulated GPS signals that were injected into the GPS receivers. As with WB jamming, the power of NB interference needed to jam GPS receivers was different on different receivers. Changing of receiver settings under NB interference conditions also showed a change in the behaviour of the receiver.
Date of Award21 Mar 2018
Original languageEnglish
Awarding Institution
  • University of Bath
SupervisorRobert Watson (Supervisor) & Cathryn Mitchell (Supervisor)

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