Planetary radio occultation technique and inversion method for YH-1 Mars mission

Investigations of planetary atmospheres, ionospheres, rings, and magnetic fields using radio science techniques have been conducted by almost every planetary mission, and are planned for many future projects. Changes in the frequency, phase, amplitude and polarization of the spacecraft radio signal, caused by passage through the atmosphere and ionosphere of the planet, were observed in rising and descending planet occultation events. Utilizing one inversion method, we can get the refractivity profiles of the atmosphere, density, temperature and pressure profiles of the neutral atmosphere, and the electron density profile of the ionosphere. Principles of the planetary radio occultation technique, physical backgrounds and module specifications of the YH-1 ground-based planetary atmosphere occultation processing system are described in this paper.