Using Radio Transmitter to Simulate Amplitude Scintillation on Radio Signals

Monday, 15 December 2014
Victoria Eccles, National Space Science and Technology Center, Huntsville, AL, United States and Ranya Ilayian, NASA Marshall Space Flight Center, Summer intern NSSTC, Huntsville, AL, United States
Rapid fluctuation of radio-frequency signal phase and/or amplitude that is generated as a signal passing through the ionosphere is commonly referred to as ionospheric scintillation. Scintillation occurs as radio frequency signals pass through a field of plasma bubbles or irregularities that can lead to signal power fading, phase cycle slips, poor GPS signals and unusable information. The goal of this research is to use radio wave transmission to simulate scintillation under controlled conditions in order examine the performance of different GPS receivers and their ability to suppress the scintillation. The information gained from the VHF (Very High Frequency) transmitter would serve as a diagnostic tool to better understand the environmental conditions that are causing these irregularities. This system could then be used as a baseline design to be upgraded by NASA engineers to 1.2 GHz – 1.5 GHz for testing out the performance of different GPS receivers. The methodology of VHF testing could be translated to higher frequencies, such as CW (Continuous Wave), which could enhance our understanding of this phenomenon.