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A Global Navigation Satellite System (GNSS) is a space-based radio-navigation system consisting of a constellation of satellites and a network of ground stations used for monitoring and control.
GNSS is being used for more precise applications, including mapping of coastlines,surveying for highway construction, airline navigation, and oil drilling.
When at least four satellites are in view, a user can obtain an accurate, three-dimensional position. At times when more than four satellites are visible from one location, the navigator enjoys an even greater level of confidence in the computed position.
For all applications on Earth, GNSS signals must pass through the ionosphere. GNSS applications are therefore affected when solar activity causes sudden variations in the density of the ionosphere.
GNSS users can be organizations or individuals. Their knowledge and understanding of space weather will also vary. Consider the following scenario. How knowledgeable do you anticipate your GNSS customers will be in comparison?
A GNSS/GPS Scenario
A customer calls and says they’ve noticed problems with the high-precision GNSS application they use during strong geomagnetic storms. They would like to be warned if such events are forecast to occur and alerted when an event is in progress. The forecaster asks about the levels of activity that give them problems and tells the customer they can sign up to receive warnings and alerts automatically when geomagnetic activity reaches certain thresholds.
One day, the customer receives an automatic G3 level warning, followed by a G3 alert an hour later. The customer calls asking how long the event is expected to last and if the geomagnetic storm would increase beyond G3 levels.
John, a SWPC forecaster, looks at the current and forecast conditions and lets the customer know G3 is the highest level of activity expected, and it should last another 18-24 hours. With this information in hand, the customer decides to suspend operations requiring precision GNSS measurements for 24 hours.