On improving the accuracy of electron density profiles obtained at high altitudes by the ionospheric sounder on the Mars Express spacecraft

2016 ◽  
Vol 121 (10) ◽  
pp. 10,117-10,129 ◽  
Author(s):  
F. Němec ◽  
D. D. Morgan ◽  
D. A. Gurnett
Keyword(s):  
Electron Density ◽  
High Altitudes ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

A Sporadic Third Layer in the Ionosphere of Mars

Science ◽  
2005 ◽  
Vol 310 (5749) ◽  
pp. 837-839 ◽  
Author(s):  
M. Pätzold ◽  
S. Tellmann ◽  
B. Häusler ◽  
D. Hinson ◽  
R. Schaa ◽  
...  
Keyword(s):  
Electron Density ◽  
Charge Exchange ◽  
Layer Structure ◽  
Electron Densities ◽  
Ionospheric Layer ◽  
Density Profiles ◽  
Mars Express ◽  
Radio Science ◽  
Martian Ionosphere ◽  
Electron Density Profiles

The daytime martian ionosphere has been observed as a two-layer structure with electron densities that peak at altitudes between about 110 and 130 kilometers. The Mars Express Orbiter Radio Science Experiment on the European Mars Express spacecraft observed, in 10 out of 120 electron density profiles, a third ionospheric layer at altitude ranges of 65 to 110 kilometers, where electron densities, on average, peaked at 0.8 × 1010 per cubic meter. Such a layer has been predicted to be permanent and continuous. Its origin has been attributed to ablation of meteors and charge exchange of magnesium and iron. Our observations imply that this layer is present sporadically and locally.

scholarly journals The processing of electron density profiles from the Mars Express MARSIS topside sounder

Radio Science ◽  
2013 ◽  
Vol 48 (3) ◽  
pp. 197-207 ◽  
Author(s):  
D. D. Morgan ◽  
O. Witasse ◽  
E. Nielsen ◽  
D. A. Gurnett ◽  
F. Duru ◽  
...  
Keyword(s):  
Electron Density ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

Mutual radio occultation experiment between ExoMars Trace Gas Orbiter and Mars Express: algorithms testing

2021 ◽  
Author(s):  
Bruno Nava ◽  
Yenca Migoya-Orue ◽  
Anton Kashcheyev ◽  
Beatriz Sánchez-Cano ◽  
Olivier Witasse ◽  
...  
Keyword(s):  
Experimental Data ◽  
Electron Density ◽  
Doppler Shift ◽  
Radio Occultation ◽  
Trace Gas ◽  
Neutral Atmosphere ◽  
Ionospheric Electron Density ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

<p>Radio Occultation (RO) is a very powerful technique to probe a planetary atmosphere, in providing vertical density profiles of the neutral atmosphere and ionosphere. The standard method uses a radio link between a spacecraft and an Earth ground station. Nevertheless, the possibility to obtain information about the Martian atmosphere with mutual RO events, using data from NASA Mars Odyssey and Mars Reconnaissance Orbiters (MRO), has been demonstrated by Ao et al. (2015).<br />Taking advantage of two European spacecraft in orbit around Mars, the European Space Agency is currently preparing experiments of mutual RO between Mars Express (MEX) and the ExoMars Trace Gas Orbiter (TGO). In preparation of MEX and TGO data inversion and analysis, a simulation-based strategy has been adopted and an algorithm able to retrieve vertical electron density profiles from Doppler shift measurements has been implemented and validated. Subsequently, in order to test the mentioned algorithm with experimental data, the same three RO events considered in the paper by Ao et al. (2015) have been processed. In particular, for each RO event, having the information about the satellites’ orbit, the (excess) Doppler shift values corresponding to the Mars Odyssey-MRO ray-paths have been converted to bending angles as a function of impact parameter. Then, assuming a spherical symmetry (Fjeldbo et al., 1971) for the ionosphere electron density, the bending angles have been transformed (through Abel integral) to a vertical refractivity profile, which, in turn, has been converted to an ionospheric electron density profile.<br />In this work, the results obtained by the application of the mentioned inversion algorithm to experimental data will be presented, with particular focus on the retrieval of the ionospheric electron density profiles.</p> <p><strong>References</strong></p> <p>Ao, C. O., C. D. Edwards Jr., D. S. Kahan, X. Pi, S. W. Asmar, and A. J. Mannucci (2015), A first demonstration of Mars crosslink occultation measurements, Radio Sci., 50, 997–1007, doi:10.1002/2015RS005750.</p> <p>Fjeldbo, G., A. J. Kliore, and V. R. Eshleman (1971), The neutral atmosphere of Venus as studied with the Mariner V radio occultation<br />experiments, Astron. J., 76, 123–140.</p>

Martian electron density profiles retrieved from Mars Express dual-frequency radio occultation measurements

2015 ◽  
Vol 55 (9) ◽  
pp. 2177-2189 ◽  
Author(s):  
S.J. Zhang ◽  
J. Cui ◽  
P. Guo ◽  
J.L. Li ◽  
J.S. Ping ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Dual Frequency ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

Mutual radio occultation experiment between ExoMars Trace Gas Orbiter and Mars Express: feasibility study and preparation for the data analysis

2020 ◽  
Author(s):  
Bruno Nava ◽  
Anton Kashcheyev ◽  
Yenca Migoya-Orue ◽  
Sandro M. Radicella ◽  
Jacob Parrott ◽  
...  
Keyword(s):  
Data Processing ◽  
Electron Density ◽  
Doppler Shift ◽  
Radio Occultation ◽  
Trace Gas ◽  
Neutral Atmosphere ◽  
Ionospheric Electron Density ◽  
Density Profiles ◽  
Mars Express ◽  
Electron Density Profiles

<p>Radio Occultation is a very powerful technique to probe a planetary atmosphere, in providing vertical density profiles of the neutral atmosphere and ionosphere. The standard method uses a radio link at S and/or X band between a spacecraft and an Earth ground station. At Mars, such measurements are conducted since the 60s. The three most recent data sets are from MGS (1998-2006), Mars Express (since 2004) and MAVEN (since 2016). Taking advantage of two European spacecraft in orbit around Mars, the European Space Agency is currently preparing an experiment that consists of mutual radio occultations between Mars Express and the ExoMars Trace Gas Orbiter. Both spacecraft use UHF transceivers that are included primarily for communication between landers on the surface of Mars and the spacecraft, where the spacecraft act as relay orbiters to pass the data from the landers on to Earth. Therefore, these mutual occultations will be performed in the UHF range (centered around a frequency of 400 MHz). The feasibility of this technique on UHF was demonstrated between the NASA Mars Odyssey and Mars Reconnaissance Orbiters [Ao et al., 2015].</p><p>In this presentation, the advantages and challenges of this technique over the traditional spacecraft to Earth occultation measurements, the plans for conducting these experiments with Mars Express and the Trace Gas Orbiter, and the envisaged data processing technique will be briefly reviewed.</p><p>Before the data becomes available, and in order to prepare the data processing, a simulation-based strategy has been adopted to implement an algorithm able to retrieve vertical electron density profiles from Doppler shift measurements. More specifically, as a first step, simulated spacecraft orbits are calculated and a Chapman function is used to obtain the electron density of the Martian ionosphere. Subsequently, a numerical 3D ray-tracing algorithm [Kashcheyev et al., 2012] is applied to compute ray trajectories in the presence of the ionosphere and the relevant Doppler shift time series corresponding to the simulated radio occultation event. Then, assuming a spherical symmetry [Fjeldbo et al., 1971] for the ionosphere electron density, the (excess) Doppler data are converted to bending angles and impact parameters. Finally, the bending angle profile is inverted (through Abel integral) to a vertical refractivity profile, which, in turn, provides information about the ionospheric electron density.</p><p>For completeness, the simulation described above has been carried out with an exponential refractivity function defining the neutral atmosphere alone and with both the Chapman and the exponential refractivity functions to simulate the whole atmosphere of Mars.</p><p>The first results obtained by means of the mentioned approaches will be presented, with particular focus on the retrieval of the ionospheric electron density profiles.</p><p><strong>References</strong></p><p>Ao, C. O., C. D. Edwards Jr., D. S. Kahan, X. Pi, S. W. Asmar, and A. J. Mannucci (2015), A first demonstration of Mars crosslink occultation measurements, Radio Sci., 50, 997–1007, doi:10.1002/2015RS005750.</p><p>Fjeldbo, G., A. J. Kliore, and V. R. Eshleman (1971), The neutral atmosphere of Venus as studied with the Mariner V radio occultation experiments, Astron. J., 76, 123–140.</p><p>Kashcheyev, A., B. Nava, and S. M. Radicella (2012), Estimation of higher-order ionospheric errors in GNSS positioning using a realistic 3-D electron density model, Radio Sci., 47, RS4008, doi:10.1029/2011RS004976</p>

Electron density profiles above the F-layer

1973 ◽  
Vol 21 (9) ◽  
pp. 1581-1586
Author(s):  
Michael Anastassiadis ◽  
Georges Moraitis ◽  
Dimitris Matsoukas
Keyword(s):  
Electron Density ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Ionospheric assimilation techniques for ARGOS Low-Resolution Airglow and Aurora Spectrograph (LORAAS) tomographically reconstructed equatorial electron density profiles

Radio Science ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. J. Sojka ◽  
J. V. Eccles ◽  
R. W. Schunk ◽  
S. McDonald ◽  
S. Thonnard ◽  
...  
Keyword(s):  
Electron Density ◽  
Low Resolution ◽  
Density Profiles ◽  
Electron Density Profiles
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