Ionospheric scintillation on radio wave signals occurs due to the presence of plasma irregularities or bubbles in the ionosphere. Bubbles are generated in the magnetic equator after the sunset due to plasma instabilities. They tend to move upward and map along the magnetic field lines over off-equatorial latitudes.
Ionospheric scintillation is a rapid change in the amplitude and phase of a radio wave when it traverses the irregularities in the ionosphere. In practical terms, this significant variation in the satellite signal amplitude level can lead them to become unavailable for any system. For example, the reduction in the number of available Global Positioning System (GPS) satellites may affect the performance and the navigational accuracy. Availability, accuracy, continuity of the service and integrity (capacity of the system to behavior without errors or faults) are important and essential requirements for critical navigation, such as civilian air travel.
The mapping of ionospheric scintillation is made through S4 index values. S4 index is the standard deviation of a minute of data in a rate of the 50 samples by second (see equation).
The mapping is made through interpolated S4 index values in the ionospheric pierce point for satellites with elevation angle higher than 30 degrees. Ionospheric pierce point is the point where the satellite signal crosses the ionosphere at an altitude of 350 km. In the map, the IONOSPHERIC PIERCE POINTS are represented by the WHITE DOTS.
Doc. Eurico Rodrigues de Paula - Technical-Scientific Coordination
Doc. Nilson Sant'Anna - Technical-Systems Coordination
Doc. Nilson Sant'Anna - Coordination
Eng. Rubens Cruz Gatto - Coordination
Visualization of the S4 scintillation index of the GPS signal, daily video and map of the stations