Review on ionospheric sounding and modeling

As an important component of solar-terrestrial space environment, the ionosphere will produce refraction, reflection, scattering and absorption effects to those radio waves which pass through it so as to affect the performance of satellite navigation, communication, radar and other radio information system. It is of great value to use various methods to detect the characteristic parameters of the ionosphere and reveal the variation law of the ionosphere. On this basis, it is of great importance to construct the ionosphere model which can meet the requirements of space science research and system application. This paper first introduces the existing common ground-based and space-based ionospheric sounding methods, and then summarizes the development status of the empirical ionospheric model, physical ionospheric model, data-driven ionospheric model and machine-learning-based ionospheric model both domestically and internationally. Finally, the ionospheric model developed for three typical scenarios are also introduced, including ionospheric delay correction for navigation system, refraction error correction for radar system and signal outage forecasting of communication/navigation system caused by ionospheric scintillation. Finally, the development trend of ionospheric sounding and modeling technology is analyzed.