Which natural phenomenon may degrade GNSS signal accuracy without interference?

Which natural phenomenon may degrade GNSS signal accuracy without interference?

• A. Solar storms
• B. Solar eclipses
• C. Earthquakes
• D. Volcanic eruptions

Answer: (A)

Solar storms disturb the ionosphere, and this ionospheric activity directly affects how GNSS signals propagate. The ionosphere contains free electrons that slow and bend radio waves; when solar storms amp up, electron density becomes highly variable and creates irregularities. This causes changes in signal delay and rapid fluctuations in phase and amplitude, known as scintillation, which can reduce positioning accuracy and even cause loss of lock for receivers. All of this happens without any deliberate interference, just natural space weather. Solar eclipses don’t create the same widespread ionospheric disruption, and earthquakes or volcanic eruptions affect ground infrastructure rather than the radio signal during its journey from satellite to receiver, so they don’t inherently degrade GNSS accuracy.

Solar storms disturb the ionosphere, and this ionospheric activity directly affects how GNSS signals propagate. The ionosphere contains free electrons that slow and bend radio waves; when solar storms amp up, electron density becomes highly variable and creates irregularities. This causes changes in signal delay and rapid fluctuations in phase and amplitude, known as scintillation, which can reduce positioning accuracy and even cause loss of lock for receivers. All of this happens without any deliberate interference, just natural space weather. Solar eclipses don’t create the same widespread ionospheric disruption, and earthquakes or volcanic eruptions affect ground infrastructure rather than the radio signal during its journey from satellite to receiver, so they don’t inherently degrade GNSS accuracy.