Amplitude variations in GPS signals as a possible indicator of ionospheric structures

Abstract

[1] The noisy and impulsive fluctuations in the CHAMP radio occultation (RO) amplitude data are similar to the Ctype and S-type ionospheric amplitude scintillations formerly observed at 1.5 GHz in the mid-latitude region in satellite-to-Earth Inmarsat links. These amplitude scintillations can be associated with different types of ionospheric structures. S-type amplitude variations can be explained by the influence of inclined plasma layers in the ionosphere where the RO signal trajectory is perpendicular to the sharp plasma gradient. Simulation indicates the possibility to reveal the spatial distribution of the electron density in the inclined ionospheric layers from analysis of the S-type RO amplitude variations.

GPS Radio Occultation: Results from CHAMP, GRACE and FORMOSAT-3/COSMIC

“…We de rived the lo ca tion of the spo radic E-lay ers us ing am pli tude vari a tions of the RO sig nal as an in di ca tor (Wickert et al 2004b, Ar ras et al 2008) . Fig ure 17 shows initial re sults of these in ves ti ga tions and dem on strates that the avail abil ity of the FORMOSAT-3/COS MIC data al lows the char ac ter iza tion of the global dis tri bu tion with un prec edented res o lu tion in time and space (Ar ras et al 2008).…”

Radio Wave Propagation Phenomena from GPS Occultation Data Analysis

“…The radio occultation (RO) method employs the highly-stable radio waves transmitted at two GPS frequencies 1 f  1575.42 MHz and 2 f  1227.60 MHz by the GPS satellites and recorded at a GPS receiver onboard low Earth orbiting (LEO) satellite to remote sense the Earth's ionosphere and neutral atmosphere [4,5,10,11,17,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]46,47,[52][53][54][55][56][59][60][61]. When applied to ionospheric investigations the RO method may be considered as a global tool and can be compared with the global Earth-and space-based radio tomography [42,43].…”

“…The RO method delivers a great amount of data on the electron density distribution in the upper and lower ionosphere that are important sources for modernizing the current information over the morphology of the ionosphere and ionospheric processes [44,45]. The RO method has been actively used to study the global distribution of sporadic E-layers in dependence of latitude, longitude, altitude and local time [5,[27][28][29][30][31][32][39][40][41][45][46][47]. These investigations have produced useful data on climatology and the formation process of sporadic E-layers which depend mainly on the Earth's magnetic field and meteor impact according to the theory of the wind shear mechanism of plasma concentration [48][49][50][51].…”

“…The refractive attenuation () X r represented by (27) and (28) satisfies the mutuality principle and does not depend on changing locations of the transmitter and receiver.…”

The FengYun-3C radio occultation sounder GNOS: a review of the mission and its early results and science applications

“…These missions have demonstrated the unique properties of the GNSS RO technique, such as high vertical resolution, high accuracy, all-weather capability and global coverage (Ware et al, 1996;Gorbunov et al, 1996;Rocken et al, 1997;Leroy, 1997;Steiner et al, 1999), and long-term stability and consistency of different RO mission observations (Foelsche et al, , 2011. Therefore, GNSS RO data products (i.e., bending angle, refractivity, temperature, 10 pressure, water vapor, and ionospheric electron density profiles) have been widely used for numerical weather prediction (NWP) (e.g., Healy and Eyre, 2000;Healy and Thepaut, 2006;Aparicio and Deblonde, 2008;Cucurull and Derber, 2008;Poli et al, 2008;Huang et al, 2010;Le Marshall et al, 2010;Harnisch et al, 2013), global climate monitoring (GCM) (e.g., Steiner et al, 2001Steiner et al, , 2009Steiner et al, , 2013Schmidt et al, 2005Schmidt et al, , 2008Schmidt et al, , 2010Loescher 15 and Kirchengast, 2008;Ho et al, 2009Ho et al, , 2012Foelsche et al, 2011a;Lackner et al, 2011) and space weather research (SWR) (Anthes, 2011;Anthes et al, 2008;Arras et al, 2008;Brahmanandam et al, 2012;Pi et al, 1997;Wickert, 2004;Yue et al, 2015).…”