Real-Time Tomographic Inversion of Truncated Ionospheric GNSS Radio Occultations

• Published in: Remote sensing (Basel, Switzerland) Vol. 15; no. 12; p. 3176
• Main Authors: Olivares-Pulido, Germán, Hernández-Pajares, Manuel, Monte-Moreno, Enric, Lyu, Haixia, Graffigna, Victoria, Cardellach, Estel, Hoque, Mainul, Prol, Fabricio S., Notarpietro, Riccardo, Garcia-Fernandez, Miquel
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.06.2023
• Subjects: Accuracy; Electron density; Electrons; Enumeration; GNSS; Inversion; Ionosphere; Ionospheric electron density; Mathematical models; Parameter estimation; Phase measurement; radio occultation; Real time; Receivers & amplifiers; Remote sensing; Satellites; Scale height; Transmitters; Spain
• ISSN: 2072-4292; 2072-4292
• DOI: 10.3390/rs15123176

This paper presents a new way of combining Abel inversion and the Chapman model with a linearly increasing scale height to retrieve ionospheric electron density vertical profiles from truncated-sounding radio-occultation data. A linear Vary–Chap model is used to cover the blind region due to data truncation, with parameters estimated by enumeration of the possible values in a grid centered around a set of parameters compatible with ionospheric physics. The resulting electron density is estimated with its corresponding error from the linear least-squares solution presenting the smaller post-fit residual on the input GNSS carrier-phase measurements. The results, tested on a set of representative GNSS RO measurements obtained by COSMIC/FORMOSAT-3, show that this method can retrieve EDVPs with a predominant absolute and relative error of 1010e−m−3 and 5%, respectively, and in less than 10 s per profile, which makes this method suitable for near real-time applications in upcoming missions such as EUMETSAT Polar System-Second Generation.