Radio occultations are commonly used to determine vertical profiles of ionospheric electron density from measurements frequency. “Frequency residuals” important intermediate data products in radio occultation experiments. Frequency residuals defined as the difference between observed and predicted values received frequency, where frequency includes all effects except refraction at target object...

GPS radio occultation (RO) signals are highly coherent and precise, and thus sufficient for holographic investigation of the atmosphere, ionosphere, and the Earth’s surface from space. In principle, three-dimensional radio-holographic remote sensing is possible by using new radio holographic equations to retrieve the radio field within the atmosphere from a radio field known at some interface o...

[1] We report new results on the structure and dynamics of the tropical atmosphere of Mars derived from a combination of radio occultation measurements by Mars Global Surveyor and simulations by a Mars general circulation model (MGCM). Radio occultation experiments sounded the equatorial atmosphere at latitudes of 36 N to 30 S during midsummer of the Northern Hemisphere (Ls = 134 –162 ), sampli...

[1] The radio occultation (RO) sounding technique that uses signals transmitted by the Global Positioning System (GPS) has evolved as an important global observing technology. In this paper, we compare RO refractivity profiles from the CHAMP (CHAllenging Minisatellite Payload) satellite mission with those calculated from radiosonde soundings over five geographical areas, each of which uses a di...

Conditions in the ionosphere of Mars vary from solar minimum to maximum due changes ionizing irradiance. Although main ionospheric layers, namely M2 layer and lower M1 layer, over cycle have been well-characterized by previous work, corresponding upper regions photochemical (?140–200 km) not. Here we investigate those using electron density profiles acquired at zenith angles 70°–90° under condi...

Radio occultation (RO) instruments using GNSS signals are specialised spaceborne receivers designed to provide highly accurate measurements from which one can derive vertical profiles of the temperature, pressure and humidity in the atmosphere, as well as profiles of electron content in the ionosphere. A family of operational RO instruments is being developed for a number of European space proj...