Editing Space weather (section)

===Ground systems===
====Spacecraft signals====
The ionosphere bends radio waves in the same manner that water in a pool bends visible light. When the medium through which such waves travel is disturbed, the light image or radio information is distorted and can become unrecognizable. The degree of distortion (scintillation) of a radio wave by the ionosphere depends on the signal frequency. Radio signals in the [[very high frequency|VHF]] band (30 to 300&nbsp;MHz) can be distorted beyond recognition by a disturbed ionosphere. Radio signals in the [[ultra high frequency|UHF]] band (300&nbsp;MHz to 3&nbsp;GHz) transit a disturbed ionosphere, but a receiver may not be able to keep locked to the carrier frequency. GPS uses signals at 1575.42&nbsp;MHz (L1) and 1227.6&nbsp;MHz (L2) that can be distorted by a disturbed ionosphere. Space weather events that corrupt GPS signals can significantly impact society. For example, the [[Wide Area Augmentation System]] <!-- (WAAS) --> operated by the US [[Federal Aviation Administration]] (FAA) is used as a navigation tool for North American commercial aviation. It is disabled by every major space weather event. Outages can range from minutes to days. Major space weather events can push the disturbed polar ionosphere 10° to 30° of latitude toward the equator and can cause large ionospheric gradients (changes in density over distance of hundreds of km) at mid and low latitude. Both of these factors can distort GPS signals.