Which term describes a GNSS error source associated with ionospheric effects?

Which term describes a GNSS error source associated with ionospheric effects?

• A. Ionosphere
• B. Troposphere
• C. Noise
• D. Selective Availability

Answer: (A)

The ionosphere is the part of the atmosphere that contains free electrons, and it directly causes GNSS signal delays that depend on frequency. This dispersive ionospheric delay—the way the signal is slowed and refracted as it travels through ionized air—is the classic ionospheric error source in GNSS measurements. The troposphere also delays signals but in a non-dispersive way and isn’t tied to ionospheric effects. Noise is random measurement noise, not a physical layer effect, and Selective Availability refers to a historical policy-based degradation of the signal rather than a natural ionospheric phenomenon. So, the term describing the GNSS error source associated with ionospheric effects is the ionosphere.

The ionosphere is the part of the atmosphere that contains free electrons, and it directly causes GNSS signal delays that depend on frequency. This dispersive ionospheric delay—the way the signal is slowed and refracted as it travels through ionized air—is the classic ionospheric error source in GNSS measurements. The troposphere also delays signals but in a non-dispersive way and isn’t tied to ionospheric effects. Noise is random measurement noise, not a physical layer effect, and Selective Availability refers to a historical policy-based degradation of the signal rather than a natural ionospheric phenomenon. So, the term describing the GNSS error source associated with ionospheric effects is the ionosphere.