749 research outputs found
Mars ionosphere TEC estimation from MARSIS data: A new approach
No full textInternational audienceWe describe a new implementation of the Contrast Method (CM) algorithm (Picardi and Sorge, 2000; Ilyushin Ya and Kunitsyn, 2004; Cartacci et al., 2013) used to correct the phase distortion of the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) (Picardi et al., 2005; Jordan et al., 2009) in its subsurface mode.The New CM is designed following an improved approach which allows not only to perform its original task but also to estimate the Total Electron Content (TEC) of the Mars ionosphere with a better accuracy respect to the past (Cartacci et al., 2013; Cartacci et al., 2017), in the nightside when the transmitted frequency is close to the ionosphere plasma frequency as well as in the dayside, thanks to a lesser use of theoretical approximations in the method development.Moreover, taking advantage of almost 16 years of MARSIS operations, corresponding to about 8700 orbits, we present an improved global map of the night side TEC variations due to the interaction with the Mars crustal magnetic field (Safaeinili et al., 2007; Cartacci et al., 2013)
Mars ionosphere TEC estimation from MARSIS data: A new approach
No full textWe describe a new implementation of the Contrast Method (CM) algorithm (Picardi and Sorge, 2000; Ilyushin Ya and Kunitsyn, 2004; Cartacci et al., 2013) used to correct the phase distortion of the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) (Picardi et al., 2005; Jordan et al., 2009) in its subsurface mode. The New CM is designed following an improved approach which allows not only to perform its original task but also to estimate the Total Electron Content (TEC) of the Mars ionosphere with a better accuracy respect to the past (Cartacci et al., 2013; Cartacci et al., 2017), in the nightside when the transmitted frequency is close to the ionosphere plasma frequency as well as in the dayside, thanks to a lesser use of theoretical approximations in the method development. Moreover, taking advantage of almost 16 years of MARSIS operations, corresponding to about 8700 orbits, we present an improved global map of the night side TEC variations due to the interaction with the Mars crustal magnetic field (Safaeinili et al., 2007; Cartacci et al., 2013).</p
Surface and subsurface radar backscattering coefficient over the Martian South Polar Layered Deposits from MARSIS data
No full textMARSIS Radar TEC estimation analysis
No full textIn this document, we describe a study to evaluate the possibility to a further improvement of the Total Electron Content of Mars’s Ionosphere using the outputs parameters produced by the Contrast Method algorithm used for the on-board and the on- ground processing of the MARSIS radar, in order to compensate the ionosphere distortions that affected the data collected by MARSIS in its subsurface operation mode
MARSIS over Elysium Planitia: mapping a subsurface structure in an area with a complex geological history.
No full textImproved estimation of Mars ionosphere total electron content
No full textWe describe an improved method to estimate the Total Electron Content (TEC) of the Mars ionosphere from the echoes recorded by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) (Picardi et al., 2005; Orosei et al., 2015) onboard Mars Express in its subsurface sounding mode. In particular, we demonstrate that this method solves the issue of the former algorithm described at (Cartacci et al., 2013), which produced an overestimation of TEC estimates on the day side.
The MARSIS signal is affected by a phase distortion introduced by the Mars ionosphere that produces a variation of the signal shape and a delay in its travel time. The new TEC estimation is achieved correlating the parameters obtained through the correction of the aforementioned effects.
In detail, the knowledge of the quadratic term of the phase distortion estimated by the Contrast Method (Cartacci et al., 2013), together with the linear term (i.e. the extra time delay), estimated through a radar signal simulator, allows to develop a new algorithm particularly well suited to estimate the TEC for solar zenith angles (SZA) lower than 95° The new algorithm for the dayside has been validated with independent data from MARSIS in its Active Ionospheric Sounding (AIS) operational mode, with comparisons with other previous algorithms based on MARSIS subsurface data, with modeling and with modeling ionospheric distortion TEC reconstruction
Studio della produzione inclusiva di adroni nelle collisioni a LEP
No full textDottorato di ricerca in fisica. 8. ciclo. Relatore A. M. Cartacci. Relatore G. GiacomelliConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
Permittivity estimation of layers beneath the northern polar layered deposits, Mars
No full textMartian Polar Layered Deposits, most likely dusty ice
are transparent to radar waves. In the North Pole bedrock
has been detected by MARSIS up to a depth about 2 Km,
whereas in the South Pole such interface has been located
at about 3.7 Km. The reflected signal is generally above
the noise and can be used to estimate the dielectric properties
of the bedrock. Assuming the permittivity of the first layer is
known, we use a simplified inversion method to extract the
bedrock relative dielectric permittivity as 4–9 below the
North PLD’s. These values are coherent with the basalt
nature and so the approach could be used to identify the
lithology beneath the Martian Poles
- …
