| Popis: |
Radio waves such as the global navigation satellite system (GNSS) signals propagating through the ionosphere will experience varying levels of absorption, refraction, scattering, and polarization shift. The two remaining effects, refraction and scattering, have important impacts on GNSS and are the main focus of this chapter. The chapter discusses ionospheric scintillation effects at high and low latitudes and their mitigation techniques. For ionospheric monitoring stations, the first line of defense is to select antenna sites that have minimal multipath reflections and to use antennas that are designed to reject multipath. The chapter provides a review of the fundamental properties of the ionosphere that impact satellite navigation signals and position, velocity, and time solutions. It focuses on the refractive effects and provides information on the GNSS measurement model, the emphasis being on the ionospheric refraction and other error terms that cannot be directly separated from the ionospheric errors. |
