Using NeQuick to reconstruct the 3D Electron Density of the Ionosphere
|
|
- Marcus Green
- 6 years ago
- Views:
Transcription
1 Using NeQuick to reconstruct the 3D Electron Density of the Ionosphere Benefits and capabilities in single frequency positioning applications Bruno Nava, Sandro Maria Radicella Telecommunications/ICT for Development Laboratory The Abdus Salam International Centre for Theoretical Physics (ICTP) Trieste, Italy Stefano Lagrasta, Fulvio Greco Satellite Systems and Applications Telespazio S.p.A. Rome, Italy Abstract The term ionospheric effect identifies a well known propagation effect, perturbing GNSS signals and ranging observables collected by a navigation receiver. In the case of a single-frequency operating device, the capability of mitigation relies upon the availability of a model for such an effect. This paper aims to demonstrate NeQuick ability of accurately reconstructing the ionospheric behavior at a given date. The ionospheric 3D model is adapted to real situations, starting from experimental input data to determine the solar effective ionization level maps : a crucial input information to properly drive NeQuick operation. Key words: NeQuick, ionosphere modelling and estimation, GNSS I. INTRODUCTION GPS users adopt the ICA/Klobuchar compensation strategy. The advent of Galileo brought to the attention a new approach, much more complex and potentially promising, that is based on the NeQuick ionosphere electron density model. NeQuick was developed at the Aeronomy and Radiopropagation Laboratory of the Abdus Salam International Centre for Theoretical Physics (ICTP, Trieste, Italy) with the collaboration of the Institute for Geophysics, Astrophysics and Meteorology of the University of Graz (Austria) [3], [4], [6], [7]. It is a quick run model particularly designed for transionospheric propagation applications able to reproduce the 3D climatologic behaviour of the ionosphere electron density. In the present work the latest version of the model, the NeQuick, has been used. Its full description, including the complete analytical formulation, can be found in [8]. In the frame of a simulation facility developed for the Italian Space Agency (ASI) and the Air Navigation Services company (ENAV), the International Centre for Theoretical Physics (ICTP) and Telespazio dealt with the problem of reproducing, at a given date, the observed ionospheric electron density. The issue is not simply to implement a realistic ionospheric profile and a delay effect on synthetic (simulated) Navigation observables. More precisely, the purpose is emulating exactly the effect that was observed over a defined time period. As a matter of fact, using the NeQuick model, different ionosphere electron density retrieval techniques have been developed, based on the model adaptation to experimental (GPS derived) data, both in terms of vertical TEC maps [5] and slant TEC measurements [13] data. This paper illustrates how the electron density reconstruction method described in [5] has been applied (for the first time) to a real case for mitigating ionospheric effects in positioning calculations. II. ABOUT IONOSPHERIC EFFECT ON RANGING The ionosphere is a dispersive medium for GNSS signals at L band, being characterized by a refractivity index n that is a function of the specific RF carrier frequency f. The ionospheric effect determines a group propagation delay on ranging signals. Thus a code range measurement, which is the primary observable available internally to a navigation receiver, suffers from an extra-length iono which is due to ionosphere: n( s ) iono 1 ds The integral is intended to be calculated along the geometric path from the receiver to the GNSS satellite that emits the related signal. An explicit formula is available for the value of' n ; in a first order approximation, one has: n( s ) 1 Ne( s ) e f 4 0 m where: N e = electron density [Electrons / m 3 ] m = rest mass of the electron = [Kg]
2 e = charge of the electron = [Coulomb] 0 = vacuum permittivity = [Farad / m] f = carrier frequency [Hz] so that: n( s ) N e( s ) f and thus, with good approximation (up to an accuracy of about 1%, for the L-band GNSS signals), it can be assumed: iono f stec f N ( s ) ds e In the previous formula, stec denotes the slant Total Electron Content (TEC) resulting from the linear integration of N e along the satellite-to-receiver ray-path. The stec is to be provided in units of [Electrons / m ] to fit Eqn. 4; however, for practical manipulation and display of numerical values, it is commonly expressed in TECU (TEC Units), where 1 TECU = [Electrons / m ]. The magnitude of the ionospheric delay effect on GNSS code range measurements is proportional to the stec and becomes more and more significant as far as low geographic latitudes are achieved [9]. III. STANDARD MITIGATION TECHNIQUES The single-frequency receiver applies a feed-forward compensation for the undesired term iono, before attempting the solution of navigation equations. derive explicitly some estimate for stec, based upon the adoption of an ionospheric model. The GPS user applies the so called ICA/Klobuchar compensation model [1], whilst SBAS (EGNOS, WAAS) architecture considers a surface grid model: in both cases, it happens like if the ionospheric effect would occur at an (ideal) thin shell surrounding the Earth at a fixed altitude h m of about 450 [Km]. The intersection of the GNSS signal optical path with the thin shell is named Ionospheric Pierce Point (IPP) ( see Figure 1. ) and it plays a central role for those models. Based upon the ionospheric thin shell approximation, the stec is obtained by a product: stec F( E ) vtec( IPP ) In the previous expression, F=F( E ) is a slant factor coefficient depending on RF propagation path elevation E w.r.t. user receiver local horizon. vtec(ipp) is the Vertical TEC, or integral of free electron density, evaluated along the zenith direction of the already mentioned IPP. Resulting compensation model takes the form: F( E ) vtec f iono GPS ICA/Klobuchar gives interpolation formulae for the (overall) right factor of Eqn. 6 and for slanting factor F(E). Model is based upon 8 parameters (only), broadcast by GPS satellite and applicable to the Earth globe. SBAS compensation technique is much more sophisticated. The EGNOS space segment transmits, as primary element, vtec values applicable at the nodes of a geographic (regional) grid. The user must interpolate acquired grid point values to achieve the vtec amount applicable at the IPP. Then, as it is the case for all thin shell based models, it must convert vtec into required stec by application of a slanting factor F(E). E IPP Navigation Satellite = Receiver Position = Ionospheric Pierce Point (IPP) E 1 = E F(E 1 ) vtec(ipp) = F(E ) vtec(ipp) E 1 E h m Figure. : Inconsistencies forced by thin shell paradigm Figure 1. : The Ionospheric Pierce Point (IPP) at the thin shell However, in order to use Eqn. 4 to this purpose, it needs to The reconstruction of stec by projecting a vtec effect, faithlessly located at the thin shell sphere, through a slanting factor F(E), brings a number of undesired drawbacks, including mathematical inconsistencies. According to Eqn. 5, two
3 different propagation paths occurring through the same IPP and characterized by equal elevation angles E 1 =E appear affected by the same stec, whilst the chance to find out stec 1 stec in real life is quite improbable (see Figure. ). An estimate of the mapping function errors for specific ionospheric conditions can be found in [14]. IV. NEQUICK APPROACH The novelty with NeQuick, compared to standard modeling and mitigation techniques already familiar to GNSS receiver technology, is that it abandons the supposition of a (virtual) thin shell surface, along with necessity of projecting a vertical effect through a slanting function. As such, NeQuick provides a full 3D representation of the electron density N e within the atmosphere. The basic inputs of the NeQuick model function are: point position {x, y, z}, UTC time t (hour of day), month m, and solar flux f10.7 (or, alternatively, sunspot number); the output is the electron concentration N e at the given location and time, being N e = N e ( s, t, m, f10.7), s = s(x, y, z). Note that solar flux f10.7 can be expressed in terms of mean sunspot number R1 according to an empirical relationship: f R1 R1 NeQuick is provided by its authors as a Fortran coded package. In the next future it will be downloadable from ITU-R web site (at present, only the previous version, NeQuick 1, is available at [11] ), along with a number of input data structured as ASCII files (with name extension.asc ). If NeQuick is intended to be used for mitigating or simulating the ionospheric effect in a GNSS receiver, then a numeric integration procedure is to be set up, for summing N e along the RF signal propagation path existing between satellite signal source and user location, as it is required by Eqn. 4. The NeQuick computer package includes specific (example) integration routines to accumulate the electron density along (any) ground-to-satellite ray-path. In the case of Galileo navigation system users, a specific version of the NeQuick model is used and an effective solar flux A z can be reconstructed from an interpolation formula, as a function of the so called Modified Dip-Latitude angle, : 0 a1 a A z a From the point of view of NeQuick, A z plays a role similar to f10.7, being characterized by the same physical units and constituting a sort of real-time estimate for Solar flux f10.7. It has to be underlined that, being A z a NeQuick-derived effective parameter, it is only valid for the model itself. As a matter of fact, the receiver will acquire current estimates for a 0, a 1, a by Galileo satellite Navigation message, whilst is computed internally by the model. In the case of NeQuick and for the purpose of this work, MoDip was obtained by direct interpolation, as a function of the intended point position {x, y, z}, using tabulated values within modip.asc file. One understands that solar activity is a key element of the NeQuick computation process. It has a short-term variability, and is used as tuning element of NeQuick in order to adapt it to a real (actual, experimental) ionospheric behavior. Other aspects of ionosphere modeling evolve as well in the mid or long term. For instance, additional data are archived in other ASCII files, allowing to obtain numerical maps describing the F-peak plasma frequency f 0 F and the propagation factor M(3000)F. 1 The temporal and spatial variations of f 0 F and M(3000)F are described by the Comité Consultatif International des Radiocommunications (CCIR) which computes proper coefficient sets to this aim []. The CCIR parameters feed a harmonics (custom) modeling, consisting first of a Fourier analysis, accounting for the monthly median diurnal variation (thus depending on hour time UT). The coefficients of Fourier expansion are, in turn, to be computed according to a worldwide description, based upon spherical (Legendre) functions, depending upon geographic longitude () and latitude () independent variables. Thus, NeQuick makes also use of the CCIR files distributed by ITU-R; such files are named CCCIRxx.asc, with xx=m+10, m denoting reference month, as a number from 1 to 1. V. PAPER OBJECTIVES The first aim of the article is to describe how a given (real) vtec map can be reconstructed, using the NeQuick model and the concept of the effective ionization level parameter, A z. This is achieved by putting into operation an approach which goes far beyond Galileo interpolation strategy given by Eqn. 8. The key element here, is obtaining an accurate functional description of A z in terms of point coordinates in space, along the propagation path of RF navigation signal. Once that A z = A z (s) values are achievable, a corresponding reconstruction of the 3D ionosphere electron density is allowed by NeQuick, along the same path. Secondly, this paper intends to show that NeQuick operation parameters related to solar activity, when fitted on an assigned vtec map, allow to provide an estimate of stec which can significantly improve the solution of positioning equations performed by a single-frequency navigation receiver. In order to verify NeQuick capability to improve the range delay corrections in single frequency positioning applications, a test case has been defined. For a given time interval, the observables collected by a geo-referenced GPS receiver have been considered and the relevant RINEX files processed to compute its position, using a 1 M(3000)F = MUF(3000) / f0f, where MUF(3000) is the highest frequency that, refracted in the ionosphere, can be received at a distance of 3000 [km].
4 standard positioning algorithm based on ICA/Klobuchar ionospheric compensation model. Over the same time window, NeQuick model has been adopted to compute all the stec values necessary to implement full ionospheric range delay corrections. In particular, for each epoch, the slant TEC values corresponding to the receiver-to-satellite links have been computed using the NeQuick model, driven by D A z grids. The structure of A z grids is very similar to that one of standard vtec maps: each grid is spaced 5 in longitude (),.5 in latitude (), and covers the whole Earth globe (7373 grid points). A z grids are obtained from a complex optimization process, driven by real vtec maps, being stored with a sampling period of 10 [min] and interpolated, both in space and time. This way, electron density N e at given space coordinates accounts for the reconstructed effective solar flux at that point, and that time. It will be shown that the prospected approach enables to gain a significant accuracy in the computation of the PVT solution. VI. ADAPTING NEQUICK TO AN ACCURATE MODELING OF OBSERVED IONOSPHERE We remind that A z is a parameter that can be considered as a proxy for the Solar activity index f10.7, and therefore is intended to be used as a primary input for the NeQuick to be able to accurately reconstruct a (real) stec along any ground-to-satellite link. Emulating the real ionospheric effect that was observed over a defined time window relies upon the possibility of reconstructing the so called effective ionization level A z = A z ( s ), using a custom approach which provides first what we defined A z grids. With a sample interval of 10 [min], 144 A z grids cover a daily period of 4 hours. Each grid stores 7373 = 539 values of A z = A z (,, t ), t being a fixed UT tag. This corresponds to parameter values per day, each computed as result from NLP optimization process; by the way, they could be a proper input to obtain the three interpolation coefficients ( a 0, a 1, a ) to be broadcast by Galileo system, foreseen by Eqn. 8. The active monitoring of ionosphere by International research centers generates data products that can be downloaded from Web sites. In particular, vtec maps are obtainable; a typical case is that one of AIUB Ionex formatted files. Ionex data appear sampled every hours; they are vtec values estimated at the nodes of a spherical coordinate grid which is spaced exactly in the same way intended for A z grids: 5 in longitude,.5 in latitude, covering the whole Earth globe (7373 points). vtec maps are now the input to the optimal determination of A z grid values. To this aim, Ionex data are preliminarily interpolated and re-sampled to obtain additional vtec maps, according to a prescribed sample time of 10 [min]. A single vtec map will originate a (single) A z grid, evaluated at the (fixed) UT = t. The optimization algorithm attempts to determine the effective ionization grid values A z = A z ( m, n ) (m=1,,73, n=1,,73) that, once ingested by NeQuick function N e = N e ( s, t, m, A z ( m, n )), with A z in place of f10.7, allow to best reconstruct the original (input, experimental) vtec map. VII. ACCURACY OF RECONSTRUCTED A Z GRIDS AND NEQUICK MODELING: COMPARING VTEC MAPS A period of high solar activity was selected, within solar cycle 3 ( see Figure 3. ), more precisely: October, 7 th -10 th 00. This interval is also geomagnetically disturbed as indicated by the World Data Center for Geomagnetism, Kyoto. Figure 3. : Solar Cycle #3 Nevertheless, such a period is interesting, as it corresponds to the MIDAN Demo campaign in Middle East (MID) region, a joint initiative of European Commission, ESA, ENAV, and Telespazio, endorsed by the ICAO MID Office. The purpose of MIDAN demonstration was to verify the feasibility of extending SBAS/EGNOS services from the original (ECAC) provision area to the ICAO MID Region. For this reason, essential logistic and technical support was locally provided by the Air Navigation Services Providers/Civil Aviation Administrations of Egypt (NANSC), Bahrein (CAA) and Saudi Arabia (PCA), which hosted three portable RIMS. Static and in-flight measurements were carried out using equipment and aircraft of ENAV, and the support of Telespazio, that performed as well: interconnection of sensor equipment with ESTB, through the Mediterranean Test Bed infrastructure at Fucino Space Centre; provision of uplink to a SBAS GEO payload (Inmarsat IOR); development of data analysis; assistance in presenting results at Fourth Meeting Of The Middle East GNSS Task Force (GNSS TF/4), occurred in Cairo (May 4 th 6 th, 004). For the test dates, RIMS observation data are still available at Telespazio, collected from GPS/SBAS receivers (Novatel Millenium). It seemed a good idea to select the associated
5 ranging measurement data set(s) to assess the validity of presented approach. The AIUB/CODE Ionex format files for the intended period were downloaded 3, and contain global ionosphere maps for DOYs 80,, 83 in 00. To make an example, at UT t = 14:00 of DOY=81, the shape of vtec is shown in Figure 4. On a first trial, the ionospheric effect was compensated according to ICA/Klobuchar model coefficients, which can be retrieved within the public available navigation message Rinex files brdcddd0.0n (with the day of year ddd = 80,,83), a standard IGS product downloadable from NASA CDDIS ftp site 4. After, having reconstructed by NLP the pertinent effective ionization level grids A z = A z (,, t ) every 10 minutes over the whole MIDAN Demo period, NeQuick processing was adopted to implement a feed-forward compensation of the ionospheric effect on code range measurements. Let us consider the case of DOY=81; the ICA/Klobuchar broadcast coefficients reported within Rinex navigation message data file brdc810.0n for such a date are: a 0 = E8 a 1 = E8 a = 1.190E7 a 3 = E8 b 0 = E+5 b 1 = E+4 b =.610E+5 b 3 = E+5 Figure 4. : AIUB/CODE vtec map 14:00) In Figure 6., the resulting (large) 3D positioning error (after ICA/Klobuchar has been applied to compensate for ionospheric effects) is shown; such a 3D error is intended as norm of vector difference between the known, geo-referenced position coordinates of the Cairo RIMS and the outcome of single-frequency positioning algorithm. The processed data slot corresponds to the time period from UT 14:00 onwards (about 3 hours): Figure 6. : 3D error [m], Klobuchar iono model (Cairo RIMS, DOY=81) The same positioning algorithm, using NeQuick ionospheric effect compensation, achieves the results shown in the following Figure 7. Figure 5. : reconstructed vtec map via NeQuick 14:00) The optimization process which drives to the achievement of an effective ionization grid A z = A z (,, t = 14:00) allows to feed NeQuick and reconstruct vtec for the same date and time, obtaining the map shown in Figure 5. VIII. ACCURACY OF RECONSTRUCTED A Z GRIDS AND NEQUICK MODELING: COMPARING POSITIONING SOLUTIONS As already said, for the selected dates, the ranging observables from 3 portable RIMS equipment have been processed, according to a standard single-point positioning algorithm. Figure 7. : 3D error [m], NeQuick iono model (Cairo RIMS, DOY=81) For the sake of a comparison, the positioning equations were also solved without applying any compensation for the ionospheric range error and the results are shown in the following Figure 8. 3 From AIUB site: ftp://ftp.unibe.ch/aiub/code/ 4 ftp://cddis.gsfc.nasa.gov/pub/gps/data/daily/
6 Figure 8. : 3D error [m], no iono mitigation (Cairo RIMS, DOY=81) In order to analyze the model performance at a different geographic location, the observations corresponding to DOY=80 for the RIMS installed at Bahrain have been processed. The results are illustrated in the following Figure 9. and Figure 10. The achieved results demonstrate the concrete possibility of using NeQuick to reproduce real, worldwide ionospheric conditions existing at a defined date, supporting as well a single frequency navigation receiver to achieve a better positioning solution. As a general consideration, NeQuick is especially effective and useful wherever ionosphere has more intense effects and larger perturbing offsets on ranging observables, like it happens at low geographic latitudes. ACKNOWLEDGMENT We take opportunity to thank National Institutions like Italian Space Agency (ASI) and Air Navigation Service Company (ENAV), which funded the Programmes which allowed to accomplish, among other activities, the R&D on NeQuick capability to emulate a defined (real) ionospheric scenario. Figure 9. : 3D error [m], Klobuchar iono model (Bahrain RIMS, DOY=80) Figure 10. : 3D error [m], NeQuick iono model (Bahrain RIMS, DOY=80) CONCLUSIONS The article is based on a sophisticated use of most recent NeQuick algorithm version, adopted to reproduce and mitigate the ionospheric delay on L-band radio-navigation ranging signals. The approach makes use of D worldwide input information on ionospheric status (vtec maps) to estimate D effective ionization level maps that can properly feed NeQuick, which is, in turn a full 3D electron density model. The paper shows first the capability of NeQuick to reconstruct a real vtec map with a high degree of truthfulness, when in challenging ionospheric environmental conditions.then, it demonstrates how the standard single-frequency receiver positioning can be improved, when operating in the same ionospheric situation. Indeed, real data have been processed over a 4-day period, by using the ESTB RIMS observables collected on October 00, during ESA/ENAV MIDAN Demo campaign in Middle East. NeQuick allowed obtaining reliable estimates of stec and a successful compensation for ranging delay iono affecting GPS C/A code measurements, thus significantly mitigating the positioning offset. REFERENCES [1] Klobuchar, J. A.: Ionospheric Effects on GPS. Chap. 1, Pag Global Positioning System: Theory and Applications. Vol 1. Published by the American Institute of Aeronautics and Astronautics, Inc., [] Bilitza, D., Sheikh, N. M., Eyfrig, R.: A global model for the height of the F-peak using M(3000)F values from the CCIR numerical map, Telecomm. J., 46, , [3] Di Giovanni, G., Radicella, S.M.: An Analytical Model of the Electron Density Profile in the Ionosphere, Advances in Space Research, 10, 11, pp. 7-30, [4] Leitinger, R., Radicella, S. M.:, The Evolution of the DGR Approach to Model Electron Density Profiles. Advances in Space Research, 7, 1, pp , 001. [5] Nava, B., P. Coisson, G. Miro Amarante, F. Azpilicueta, S. M. Radicella: A model assisted ionospheric electron density reconstruction method based on VTEC data ingestion. Annals Geophys., 48, , 005. [6] Leitinger, R., Zhang, M., Radicella, S. M.: An improved bottomside for the ionospheric electron density model NeQuick, Annals of Geophysics, Vol. 48, N. 3, 005. [7] Coïsson, P., Radicella, S.M., Leitinger, R., Nava, B.: Topside electron density in IRI and NeQuick: features and limitations, Adv. Space Res., 37. pp , 006. [8] Nava, B., Coïsson, P., Radicella, S. M.: A new version of the NeQuick ionosphere electron density model. Geophysical Research Abstracts, Vol. 9, 007. [9] Gende, M. A., Radicella, S. M., Nava, B., Brunini, C.: Ionospheric Effect in Instantaneous Positioning. ION NTM 003, Anaheim, CA, 003. [10] Radicella, S.M., Nava, B., Coïsson, P.: Ionospheric Models For Gnss Single Frequency Range Delay Corrections. Fisica Della Tierra Pag. 7-39, No. 0, 008. [11] NeQuick 1 software package (Fortran 77 source code) at ITU: [1] ICAO Report of the Fourth Meeting of the Middle East GNSS Task Force (GNSS TF/4) Cairo, 4 6 May 004, Report.pdf [13] Nava, B., S. M. Radicella, R. Leitinger, and P. Coïsson (006), A nearreal-time model-assisted ionosphere electron density retrieval method, Radio Sci., 41, RS6S16, doi:10.109/005rs [14] B. Nava, S.M. Radicella, R. Leitinger, P. Coïsson, "Use or total electron content data to analyze ionosphere electron density gradients", Advances in Space Research, vol. 39 N. 8, , doi: /j.asr , 007
NeQuick model Overview. Y. Migoya Orue, S. M. Radicella, B. Nava, K. Alazo Cuartas and A. Kashcheyev (T/ICT4D) ICTP
NeQuick model Overview Y. Migoya Orue, S. M. Radicella, B. Nava, K. Alazo Cuartas and A. Kashcheyev (T/ICT4D) ICTP United Nations/Argentina Workshop on the Applications of Global Navigation Satellite Systems,
More informationThe NeQuick ionosphere electron density model: GNSS applications
Navigation solutions powered by Europe The NeQuick ionosphere electron density model: GNSS applications B. Nava (1), S.M. Radicella (1), R. Orus (2) (1) ICTP - Trieste, Italy (2) ESTEC/TEC-EEP; ESA - Noordwijk,
More informationThe NeQuick model genesis, uses and evolution
Vol52,3,2009 20-09-2009 19:06 Pagina 417 ANNALS OF GEOPHYSICS, VOL. 52, N. 3/4, June/August 2009 The NeQuick model genesis, uses and evolution Sandro M. Radicella ARPL, The Abdus Salam ICTP, Trieste, Italy
More informationSatellite Navigation Science and Technology for Africa. 23 March - 9 April, The African Ionosphere
2025-28 Satellite Navigation Science and Technology for Africa 23 March - 9 April, 2009 The African Ionosphere Radicella Sandro Maria Abdus Salam Intern. Centre For Theoretical Physics Aeronomy and Radiopropagation
More informationIonospheric Range Error Correction Models
www.dlr.de Folie 1 >Ionospheric Range Error Correction Models> N. Jakowski and M.M. Hoque 27/06/2012 Ionospheric Range Error Correction Models N. Jakowski and M.M. Hoque Institute of Communications and
More informationData ingestion into NeQuick 2
RADIO SCIENCE, VOL. 46,, doi:10.1029/2010rs004635, 2011 Data ingestion into NeQuick 2 B. Nava, 1 S. M. Radicella, 1 and F. Azpilicueta 2,3 Received 31 December 2010; revised 2 June 2011; accepted 9 June
More informationAssessment of EGNOS performance in worst ionosphere conditions (October and November 2003 storm)
European Navigation Conference 2005 Munich Assessment of EGNOS performance in worst ionosphere conditions (October and November 2003 storm) Authors: Cristoforo Montefusco 1, Javier Ventura-Traveset 1,
More informationAn Assessment of Mapping Functions for VTEC Estimation using Measurements of Low Latitude Dual Frequency GPS Receiver
An Assessment of Mapping Functions for VTEC Estimation using Measurements of Low Latitude Dual Frequency GPS Receiver Mrs. K. Durga Rao 1 Asst. Prof. Dr. L.B.College of Engg. for Women, Visakhapatnam,
More informationPlasma effects on transionospheric propagation of radio waves II
Plasma effects on transionospheric propagation of radio waves II R. Leitinger General remarks Reminder on (transionospheric) wave propagation Reminder of propagation effects GPS as a data source Some electron
More informationA study of the ionospheric effect on GBAS (Ground-Based Augmentation System) using the nation-wide GPS network data in Japan
A study of the ionospheric effect on GBAS (Ground-Based Augmentation System) using the nation-wide GPS network data in Japan Takayuki Yoshihara, Electronic Navigation Research Institute (ENRI) Naoki Fujii,
More informationNeQuick model performance analysis for GNSS mass market receivers positioning
UN/ICTP Workshop on GNSS NeQuick model performance analysis for GNSS mass market receivers positioning Parthenope University of Naples salvatore.gaglione@uniparthenope.it 1 PANG Research Group composed
More informationEstimation Method of Ionospheric TEC Distribution using Single Frequency Measurements of GPS Signals
Estimation Method of Ionospheric TEC Distribution using Single Frequency Measurements of GPS Signals Win Zaw Hein #, Yoshitaka Goto #, Yoshiya Kasahara # # Division of Electrical Engineering and Computer
More informationAn improved bottomside for the ionospheric electron density model NeQuick
ANNALS OF GEOPHYSICS, VOL. 48, N. 3, June 2005 An improved bottomside for the ionospheric electron density model NeQuick Reinhart Leitinger ( 1 ), Man-Lian Zhang ( 2 ) and Sandro M. Radicella ( 3 ) ( 1
More informationNeQuick model performance analysis for GNSS mass market receivers positioning
UN/ICTP Workshop on GNSS NeQuick model performance analysis for GNSS mass market receivers positioning Parthenope University of Naples salvatore.gaglione@uniparthenope.it 1 PANG Research Group composed
More informationIonogram inversion F1-layer treatment effect in raytracing
ANNALS OF GEOPHYSICS, VOL. 48, N. 3, June 2005 Ionogram inversion F1-layer treatment effect in raytracing Gloria Miró Amarante ( 1 ), Man-Lian Zhang ( 2 ) and Sandro M. Radicella ( 1 ) ( 1 ) The Abdus
More informationIonospheric Corrections for GNSS
Ionospheric Corrections for GNSS The Atmosphere and its Effect on GNSS Systems 14 to 16 April 2008 Santiago, Chile Ing. Roland Lejeune Overview Ionospheric delay corrections Core constellations GPS GALILEO
More informationTOWARD A SIRGAS SERVICE FOR MAPPING THE IONOSPHERE S S F2 PEACK PARAMETERS
TOWARD A SIRGAS SERVICE FOR MAPPING THE IONOSPHERE S S F2 PEACK PARAMETERS C Brunini, F Azpilicueta, M Gende Geodesia Espacial y Aeronomía Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional
More informationROTI Maps: a new IGS s ionospheric product characterizing the ionospheric irregularities occurrence
3-7 July 2017 ROTI Maps: a new IGS s ionospheric product characterizing the ionospheric irregularities occurrence Iurii Cherniak Andrzej Krankowski Irina Zakharenkova Space Radio-Diagnostic Research Center,
More informationDATA AND PRODUCT EXCHANGE IN THE CONTEXT OF WIS. ITU discussions on ionospheric products and formats. (Submitted by the WMO Secretariat)
WORLD METEOROLOGICAL ORGANIZATION COMMISSION FOR BASIC SYSTEMS COMMISSION FOR AERONAUTICAL METEOROLOGY INTER-PROGRAMME COORDINATION TEAM ON SPACE WEATHER ICTSW-5/Doc. 6.2 (28.X.2014) ITEM: 6.2 FIFTH SESSION
More informationDeveloping systems for ionospheric data assimilation
Developing systems for ionospheric data assimilation Making a quantitative comparison between observations and models A.C. Bushell, 5 th European Space Weather Week, Brussels, 20 th November 2008 Collaborators
More information4 Space plasma effects on Earth-space and satellite-to-satellite communications: Working Group 4 overview
ANNALS OF GEOPHYSICS, SUPPLEMENT TO VOL. 47, N. 2/3, 2004 4 Space plasma effects on Earth-space and satellite-to-satellite communications: Working Group 4 overview SANDRO M. RADICELLA ( 1 ) and ERSIN TULUNAY
More informationInfluence of Major Geomagnetic Storms Occurred in the Year 2011 On TEC Over Bangalore Station In India
International Journal of Electronics and Communication Engineering. ISSN 0974-2166 Volume 6, Number 1 (2013), pp. 105-110 International Research Publication House http://www.irphouse.com Influence of Major
More informationApril - 1 May, GNSS Derived TEC Data Calibration
2333-44 Workshop on Science Applications of GNSS in Developing Countries (11-27 April), followed by the: Seminar on Development and Use of the Ionospheric NeQuick Model (30 April-1 May) 11 April - 1 May,
More informationStudy of the Ionosphere Irregularities Caused by Space Weather Activity on the Base of GNSS Measurements
Study of the Ionosphere Irregularities Caused by Space Weather Activity on the Base of GNSS Measurements Iu. Cherniak 1, I. Zakharenkova 1,2, A. Krankowski 1 1 Space Radio Research Center,, University
More informationTEC Estimation Using GNSS. Luigi Ciraolo, ICTP. Kigali, July 9th 2014
TEC Estimation Using GNSS Luigi Ciraolo, ICTP Workshop: African School on Space Science: Related Applications and Awareness for Sustainable Development of the Region Kigali, July 9th 2014 GNSS observables
More informationESTIMATION OF IONOSPHERIC DELAY FOR SINGLE AND DUAL FREQUENCY GPS RECEIVERS: A COMPARISON
ESTMATON OF ONOSPHERC DELAY FOR SNGLE AND DUAL FREQUENCY GPS RECEVERS: A COMPARSON K. Durga Rao, Dr. V B S Srilatha ndira Dutt Dept. of ECE, GTAM UNVERSTY Abstract: Global Positioning System is the emerging
More information[EN-107] Impact of the low latitude ionosphere disturbances on GNSS studied with a three-dimensional ionosphere model
ENRI Int. Workshop on ATM/CNS. Tokyo, Japan (EIWAC21) [EN-17] Impact of the low latitude ionosphere disturbances on GNSS studied with a three-dimensional ionosphere model + S. Saito N. FUjii Communication
More informationTotal Electron Content (TEC) and Model Validation at an Equatorial Region
Total Electron Content (TEC) and Model Validation at an Equatorial Region NORSUZILA YA ACOB 1, MARDINA ABDULLAH 2,* MAHAMOD ISMAIL 2,* AND AZAMI ZAHARIM 3,** 1 Faculty of Electrical Engineering, Universiti
More informationGPS Based Ionosphere Mapping Using PPP Method
Salih ALCAY, Cemal Ozer YIGIT, Cevat INAL, Turkey Key words: GIMs, IGS, Ionosphere mapping, PPP SUMMARY Mapping of the ionosphere is a very interesting subject within the scientific community due to its
More informationData Assimilation into Ionospheric Models
Data Assimilation into Ionospheric Models Bruno Nava Karl Franzens University Graz, Graz, Austria ICTP, Trieste, Italy Supervisor: Prof. H. Biernat Karl Franzens University Graz, Graz, Austria Advisor:
More informationImaging of the equatorial ionosphere
ANNALS OF GEOPHYSICS, VOL. 48, N. 3, June 2005 Imaging of the equatorial ionosphere Massimo Materassi ( 1 ) and Cathryn N. Mitchell ( 2 ) ( 1 ) Istituto dei Sistemi Complessi, CNR, Sesto Fiorentino (FI),
More informationIonospheric Effects on Aviation
Ionospheric Effects on Aviation Recent experience in the observation and research of ionospheric irregularities, gradient anomalies, depletion walls, etc. in USA and Europe Stan Stankov, René Warnant,
More informationTo Estimate The Regional Ionospheric TEC From GEONET Observation
To Estimate The Regional Ionospheric TEC From GEONET Observation Jinsong Ping(Email: jsping@miz.nao.ac.jp) 1,2, Nobuyuki Kawano 2,3, Mamoru Sekido 4 1. Dept. Astronomy, Beijing Normal University, Haidian,
More informationEFFECTS OF SCINTILLATIONS IN GNSS OPERATION
- - EFFECTS OF SCINTILLATIONS IN GNSS OPERATION Y. Béniguel, J-P Adam IEEA, Courbevoie, France - 2 -. Introduction At altitudes above about 8 km, molecular and atomic constituents of the Earth s atmosphere
More information8 Total electron content A key parameter in propagation: measurement and use in ionospheric imaging
ANNALS OF GEOPHYSICS, SUPPLEMENT TO VOL. 47, N. 2/3, 2004 8 Total electron content A key parameter in propagation: measurement and use in ionospheric imaging LEONARD KERSLEY ( 1 ), DANIEL MALAN ( 1 ),
More informationPresent and future IGS Ionospheric products
Present and future IGS Ionospheric products Andrzej Krankowski, Manuel Hernández-Pajares, Joachim Feltens, Attila Komjathy, Stefan Schaer, Alberto García-Rigo, Pawel Wielgosz Outline Introduction IGS IONO
More informationActivities of the JPL Ionosphere Group
Activities of the JPL Ionosphere Group On-going GIM wor Submit rapid and final GIM TEC maps for IGS combined ionosphere products FAA WAAS & SBAS analysis Error bounds for Brazilian sector, increasing availability
More informationReport of the Working Group B: Enhancement of Global Navigation Satellite Systems (GNSS) Services Performance
Report of the Working Group B: Enhancement of Global Navigation Satellite Systems (GNSS) Services Performance 1. The Working Group on Enhancement of Global Navigation Satellite Systems (GNSS) Service Performance
More informationGPS interfrequency biases and total electron content errors in ionospheric imaging over Europe
RADIO SCIENCE, VOL. 41,, doi:10.1029/2005rs003269, 2006 GPS interfrequency biases and total electron content errors in ionospheric imaging over Europe Richard M. Dear 1 and Cathryn N. Mitchell 1 Received
More informationDetection of Abnormal Ionospheric Activity from the EPN and Impact on Kinematic GPS positioning
Detection of Abnormal Ionospheric Activity from the EPN and Impact on Kinematic GPS positioning N. Bergeot, C. Bruyninx, E. Pottiaux, S. Pireaux, P. Defraigne, J. Legrand Royal Observatory of Belgium Introduction
More informationGeneration of Klobuchar Coefficients for Ionospheric Error Simulation
Research Paper J. Astron. Space Sci. 27(2), 11722 () DOI:.14/JASS..27.2.117 Generation of Klobuchar Coefficients for Ionospheric Error Simulation Chang-Moon Lee 1, Kwan-Dong Park 1, Jihyun Ha 2, and Sanguk
More informationSpace geodetic techniques for remote sensing the ionosphere
Space geodetic techniques for remote sensing the ionosphere Harald Schuh 1,2, Mahdi Alizadeh 1, Jens Wickert 2, Christina Arras 2 1. Institute of Geodesy and Geoinformation Science, Technische Universität
More informationPositioning performance of the NTCM model driven by GPS Klobuchar model parameters
J. Space Weather Space Clim. 2018, 8, A18 M.M. Hoque et al., Published by EDP Sciences 2018 https://doi.org/10.1051/swsc/2018009 Space weather effects on GNSS and their mitigation Available online at:
More informationSWIPPA Products COMMENTS
PRODUCT SWIPPA-DLR-CNF-PRO-DAT-TEC SWIPPA-DLR-RST-PRO-MAP-TEC COMMENTS TEC : Total Electron Content Vertical Source: GNSS measurements; SWIPPA-DLR-CNF-PRO-DAT-TMP SWIPPA-DLR-RST-PRO-MAP-TMP TEC-TMP : Total
More informationIonospheric Imprint to LOFAR
Ionospheric Imprint to LOFAR Norbert Jakowski Institute of Communications und Navigation German Aerospace Center Kalkhorstweg 53, D-17235 Neustrelitz, Germany LOFAR Workshop, 8/9 November 2010, Potsdam,
More informationEUROPEAN GNSS (GALILEO) INITIAL SERVICES NAVIGATION SOLUTIONS POWERED BY E U R O P E OPEN SERVICE QUARTERLY PERFORMANCE REPORT
NAVIGATION SOLUTIONS POWERED BY E U R O P E EUROPEAN GNSS (GALILEO) INITIAL SERVICES OPEN SERVICE QUARTERLY PERFORMANCE REPORT JANUARY - MARCH 2018 TABLE OF CONTENTS 1 INTRODUCTION... 1 2 EXECUTIVE SUMMARY...
More informationCombining ionosonde with ground GPS data for electron density estimation
Journal of Atmospheric and Solar-Terrestrial Physics 65 (23) 683 691 www.elsevier.com/locate/jastp Combining ionosonde with ground GPS data for electron density estimation M. Garca-Fernandez a;, M. Hernandez-Pajares
More informationAn Investigation of Local-Scale Spatial Gradient of Ionospheric Delay Using the Nation-Wide GPS Network Data in Japan
An Investigation of Local-Scale Spatial Gradient of Ionospheric Delay Using the Nation-Wide GPS Network Data in Japan Takayuki Yoshihara, Takeyasu Sakai and Naoki Fujii, Electronic Navigation Research
More informationAutomated daily processing of more than 1000 ground-based GPS receivers for studying intense ionospheric storms
RADIO SCIENCE, VOL. 40,, doi:10.1029/2005rs003279, 2005 Automated daily processing of more than 1000 ground-based GPS receivers for studying intense ionospheric storms Attila Komjathy, Lawrence Sparks,
More informationNAVIGATION SYSTEMS PANEL (NSP) NSP Working Group meetings. Impact of ionospheric effects on SBAS L1 operations. Montreal, Canada, October, 2006
NAVIGATION SYSTEMS PANEL (NSP) NSP Working Group meetings Agenda Item 2b: Impact of ionospheric effects on SBAS L1 operations Montreal, Canada, October, 26 WORKING PAPER CHARACTERISATION OF IONOSPHERE
More informationLEO GPS Measurements to Study the Topside Ionospheric Irregularities
LEO GPS Measurements to Study the Topside Ionospheric Irregularities Irina Zakharenkova and Elvira Astafyeva 1 Institut de Physique du Globe de Paris, Paris Sorbonne Cité, Univ. Paris Diderot, UMR CNRS
More informationIONEX: The IONosphere Map EXchange Format Version 1.1
IONEX: The IONosphere Map EXchange Format Version 1.1 Stefan Schaer, Werner Gurtner Astronomical Institute, University of Berne, Switzerland stefan.schaer@aiub.unibe.ch Joachim Feltens ESA/ESOC, Darmstadt,
More informationCombined global models of the ionosphere
Combined global models of the ionosphere S. Todorova (1), T. Hobiger (2), H. Schuh (1) (1) Institute of Geodesy and Geophysics (IGG), Vienna University of Technology (2) Space-Time Standards Group, Kashima
More informationMonitoring the Auroral Oval with GPS and Applications to WAAS
Monitoring the Auroral Oval with GPS and Applications to WAAS Peter J. Stewart and Richard B. Langley Geodetic Research Laboratory Department of Geodesy and Geomatics Engineering University of New Brunswick
More informationSpatial and Temporal Variations of GPS-Derived TEC over Malaysia from 2003 to 2009
Spatial and Temporal Variations of GPS-Derived TEC over Malaysia from 2003 to 2009 Leong, S. K., Musa, T. A. & Abdullah, K. A. UTM-GNSS & Geodynamics Research Group, Infocomm Research Alliance, Faculty
More informationRECOMMENDATION ITU-R P HF PROPAGATION PREDICTION METHOD* (Question ITU-R 223/3)
Rec. ITU-R P.533-6 1 RECOMMENDATION ITU-R P.533-6 HF PROPAGATION PREDICTION METHOD* (Question ITU-R 223/3) Rec. ITU-R P.533-6 (1978-1982-1990-1992-1994-1995-1999) The ITU Radiocommunication Assembly, considering
More informationICTP- TREGA project Sharing experience with Euromed neighbouring countries
07/05/2015 Euromed GNSSII/MEDUSA project, Tunis 1 ICTP- TREGA project Sharing experience with Euromed neighbouring countries H.R. Ngaya,C. Paparini, O.E. Abe, X. Otero Villamide, S. M. Radicella, B. Nava
More informationComparative analysis of the effect of ionospheric delay on user position accuracy using single and dual frequency GPS receivers over Indian region
Indian Journal of Radio & Space Physics Vol. 38, February 2009, pp. 57-61 Comparative analysis of the effect of ionospheric delay on user position accuracy using single and dual frequency GPS receivers
More informationThe added value of new GNSS to monitor the ionosphere
The added value of new GNSS to monitor the ionosphere R. Warnant 1, C. Deprez 1, L. Van de Vyvere 2 1 University of Liege, Liege, Belgium. 2 M3 System, Wavre, Belgium. Monitoring TEC for geodetic applications
More informationOUTLINE. Satellite Navigation - Overview. Satellite Navigation provides. Satellite Navigation Systems Overview Applications Main propagation effects
First European Space Weather Week 9 Nov 3 Dec 004 Noordwijk, The Netherlands Session Science to Application # Ionosphere, Positioning & Telecommunication Ionospheric Effects on Satellite Navigation Systems
More informationExamination of Three Empirical Atmospheric Models
Examination of Three Empirical Atmospheric Models A Presentation Given to The Department of Physics Utah State University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy
More informationThe impact of low-latency DORIS data on near real-time VTEC modeling
The impact of low-latency DORIS data on near real-time VTEC modeling Eren Erdogan, Denise Dettmering, Michael Schmidt, Andreas Goss 2018 IDS Workshop Ponta Delgada (Azores Archipelago), Portugal, 24-26
More informationCALIBRATING GNSS SATELLITE ANTENNA GROUP-DELAY VARIATIONS USING SPACE AND GROUND RECEIVERS
IGS WORKSHOP 2014 CALIBRATING GNSS SATELLITE ANTENNA GROUP-DELAY VARIATIONS USING SPACE AND GROUND RECEIVERS June 23-27, 2014 - PASADENA, CALIFORNIA Plenary PY06: Infrastructure and Calibration David CALLE
More informationGPS Ray Tracing to Show the Effect of Ionospheric Horizontal Gradeint to L 1 and L 2 at Ionospheric Pierce Point
Proceeding of the 2009 International Conference on Space Science and Communication 26-27 October 2009, Port Dickson, Negeri Sembilan, Malaysia GPS Ray Tracing to Show the Effect of Ionospheric Horizontal
More informationEFFECTS OF IONOSPHERIC SMALL-SCALE STRUCTURES ON GNSS
EFFECTS OF IONOSPHERIC SMALL-SCALE STRUCTURES ON GNSS G. Wautelet, S. Lejeune, R. Warnant Royal Meteorological Institute of Belgium, Avenue Circulaire 3 B-8 Brussels (Belgium) e-mail: gilles.wautelet@oma.be
More informationStudy of the ionosphere of Mars: application and limitations of the Chapman-layer model
Highlights of Spanish Astrophysics VI, Proceedings of the IX Scientific Meeting of the Spanish Astronomical Society held on September 13-17, 2010, in Madrid, Spain. M. R. Zapatero Osorio et al. (eds.)
More information2 Assessment of space plasma effects for satellite applications: Working Group 2 overview
ANNALS OF GEOPHYSICS, SUPPLEMENT TO VOL. 47, N. 2/3, 2004 2 Assessment of space plasma effects for satellite applications: Working Group 2 overview REINHART LEITINGER ( 1 ) and NORBERT JAKOWSKI ( 2 ) (
More informationINTERNATIONAL CIVIL AVIATION ORGANIZATION
INTERNATIONAL CIVIL AVIATION ORGANIZATION AFI PLANNING AND IMPLEMENTATION REGIONAL GROUP EIGHTEENTH MEETING (APIRG/18) Kampala, Uganda (27 30 March 2012) Agenda Item 3: Performance Framework for Regional
More informationIonospheric sounding at the RMI Geophysical Centre in Dourbes: digital ionosonde performance and ionospheric monitoring service applications
Solar Terrestrial Centre of Excellence Ionospheric sounding at the RMI Geophysical Centre in Dourbes: digital ionosonde performance and ionospheric monitoring service applications S. Stankov, T. Verhulst,
More informationIRI-Plas Optimization Based Ionospheric Tomography
IRI-Plas Optimization Based Ionospheric Tomography Onur Cilibas onurcilibas@gmail.com.tr Umut Sezen usezen@hacettepe.edu.tr Feza Arikan arikan@hacettepe.edu.tr Tamara Gulyaeva IZMIRAN 142190 Troitsk Moscow
More informationanalysis of GPS total electron content Empirical orthogonal function (EOF) storm response 2016 NEROC Symposium M. Ruohoniemi (3)
Empirical orthogonal function (EOF) analysis of GPS total electron content storm response E. G. Thomas (1), A. J. Coster (2), S.-R. Zhang (2), R. M. McGranaghan (1), S. G. Shepherd (1), J. B. H. Baker
More informationThe European Server for Ionospheric specification and forecasting: Final results from DIAS project
The European Server for Ionospheric specification and forecasting: Final results from DIAS project A. Belehaki (1), Lj. Cander (2), B. Zolesi (3), J. Bremer (4), C. Juren (5), I. Stanislawska (6), D. Dialetis
More informationSBAS DFMC performance analysis with the SBAS DFMC Service Volume software Prototype (DSVP)
SBAS DFMC performance analysis with the SBAS DFMC Service Volume software Prototype (DSVP) D. Salos, M. Mabilleau, Egis Avia C. Rodriguez, H. Secretan, N. Suard, CNES (French Space Agency) Email: Daniel.salos@egis.fr
More informationEffects of magnetic storms on GPS signals
Effects of magnetic storms on GPS signals Andreja Sušnik Supervisor: doc.dr. Biagio Forte Outline 1. Background - GPS system - Ionosphere 2. Ionospheric Scintillations 3. Experimental data 4. Conclusions
More informationValidation of new ionospheric parameter modeling
Validation of new ionospheric parameter modeling MALTSEVA OLGA, ZHBANKOV GENNAGIJ Institute for Physics Southern Federal University Stachki, 194, Roston-on-Don RUSSIA mai@ip.rsu.ru Abstract: - The growing
More informationJames M Anderson. in collaboration with Jan Noordam and Oleg Smirnov. MPIfR, Bonn, 2006 Dec 07
Ionospheric Calibration for Long-Baseline, Low-Frequency Interferometry in collaboration with Jan Noordam and Oleg Smirnov Page 1/36 Outline The challenge for radioastronomy Introduction to the ionosphere
More informationROM SAF CDOP-2. Visiting Scientist Report 28:
: A new software tool for reducing systematic residual ionospheric errors in GNSS-RO level 3 products Matthew Angling University of Birmingham Danish Meteorological Institute (DMI) European Centre for
More informationRECOMMENDATION ITU-R P HF propagation prediction method *
Rec. ITU-R P.533-7 1 RECOMMENDATION ITU-R P.533-7 HF propagation prediction method * (Question ITU-R 3/3) (1978-198-1990-199-1994-1995-1999-001) The ITU Radiocommunication Assembly, considering a) that
More informationDetermination of Regional TEC Values by GNSS Measurements, A Case Study: Central Anatolia Sample, Turkey
Presented at the FIG Working Week 2017, May 29 - June 2, 2017 in Helsinki, Finland Determination of Regional TEC Values by GNSS Measurements, A Case Study: Central Anatolia Sample, Turkey Fuat BAŞÇİFTÇİ,
More informationIonospheric bending correction for GNSS radio occultation signals
RADIO SCIENCE, VOL. 46,, doi:10.109/010rs004583, 011 Ionospheric bending correction for GNSS radio occultation signals M. M. Hoque 1 and N. Jakowski 1 Received 30 November 010; revised 1 April 011; accepted
More informationModeling and Simulation of GNSS with NS2
Modeling and Simulation of GSS with S Tiziano Inzerilli, Daniele Lo Forti, Vincenzo Suraci 3 University of Rome La Sapienza, D.I.S inzerilli@dis.uniroma.it, danyloforti@tiscali.it, vincenzo.suraci@dis.uniroma.it
More informationModeling M(3000)F2 based on empirical orthogonal function analysis method
RADIO SCIENCE, VOL. 43,, doi:10.1029/2007rs003694, 2008 Modeling M(3000)F2 based on empirical orthogonal function analysis method Chunxu Liu, 1,2 Man-Lian Zhang, 1 Weixing Wan, 1 Libo Liu, 1 and Baiqi
More informationAssimilation Ionosphere Model
Assimilation Ionosphere Model Robert W. Schunk Space Environment Corporation 399 North Main, Suite 325 Logan, UT 84321 phone: (435) 752-6567 fax: (435) 752-6687 email: schunk@spacenv.com Award #: N00014-98-C-0085
More informationIGS Products for the Ionosphere
1 IGS Products for the Ionosphere J. Feltens 1 and S. Schaer 2 1. EDS at Flight Dynamics Division, ESA, European Space Operations Centre, Robert-Bosch-Str. 5, D-64293 Darmstadt, Germany 2. Astronomical
More informationCurrent GPS Monitoring Activities in Thailand and Total Electron Content (TEC) Study at Chumphon and Bangkok, Thailand
EIWACS 2010 The 2nd ENRI International Workshop on ATM/CNS 10-12 November, 2010, Tokyo, Japan Current GPS Monitoring Activities in Thailand and Total Electron Content (TEC) Study at Chumphon and Bangkok,
More informationInternational GNSS Service Workshop 2017
International GNSS Service Workshop 2017 The Recent Activities of CAS Ionosphere Analysis Center on GNSS Ionospheric Modeling within IGS CAS: Chinese Academy of Sciences Yunbin Yuan*, Zishen Li, Ningbo
More informationSBAS solution GCC, Yemen and Iraq System baseline and performance
SBAS solution GCC, Yemen and Iraq System baseline and performance ACAC Workshop Rabat 7 & 8 November 2017 1 2017 Thales Alenia Space PROPRIETARY C O M MINFORMATION E R C I A L I N THALES C O ALENIA N F
More informationOperational Products of the Space Weather Application Center Ionosphere (SWACI) and capabilities of their use
Operational Products of the Space Weather Application Center Ionosphere (SWACI) and capabilities of their use N. Jakowski, C. Borries, V. Wilken, K.D. Missling, H. Barkmann, M. M. Hoque, M. Tegler, C.
More informationGalileo Single Frequency Ionospheric Correction: Performances in Terms of Position
Galileo Single Frequency Ionospheric Correction: Performances in Terms of Position Benoît Bidaine, Matthieu Lonchay Fund for Scientific Research FNRS University of Liège (ULg) - Geomatics Unit, Allée du
More informationTEC and Scintillation Study of Equatorial Ionosphere: A Month Campaign over Sipitang and Parit Raja Stations, Malaysia
American J. of Engineering and Applied Sciences (1): 44-49, 009 ISSN 1941-700 009 Science Publications TEC and Scintillation Study of Equatorial Ionosphere: A Month Campaign over Sipitang and Parit Raja
More informationKalman Filtering of the GPS Data and NeQuick and NHPC Comparison
WDS'12 Proceedings of Contributed Papers, Part II, 210 215, 2012. ISBN 978-80-7378-225-2 MATFYZPRESS Kalman Filtering of the GPS Data and NeQuick and NHPC Comparison Z. Mošna, 1,2 D. Kouba, 1,2 P. Koucká
More informationimaging of the ionosphere and its applications to radio propagation Fundamentals of tomographic Ionospheric Tomography I: Ionospheric Tomography I:
Ionospheric Tomography I: Ionospheric Tomography I: Fundamentals of tomographic imaging of the ionosphere and its applications to radio propagation Summary Introduction to tomography Introduction to tomography
More informationRECOMMENDATION ITU-R F.1404*
Rec. ITU-R F.1404 1 RECOMMENDATION ITU-R F.1404* Rec. ITU-R F.1404 MINIMUM PROPAGATION ATTENUATION DUE TO ATMOSPHERIC GASES FOR USE IN FREQUENCY SHARING STUDIES BETWEEN SYSTEMS IN THE FIXED SERVICE AND
More informationTEC Prediction Model using Neural Networks over a Low Latitude GPS Station
ISSN: 223-237, Volume-2, Issue-2, May 2 TEC Prediction Model using Neural Networks over a Low GPS Station D.Venkata.Ratnam, B.Venkata Dinesh, B.Tejaswi, D.Praveen Kumar, T.V.Ritesh, P.S.Brahmanadam, G.Vindhya
More informationThree-dimensional and numerical ray tracing on a phenomenological ionospheric model
Three-dimensional and numerical ray tracing on a phenomenological ionospheric model Lung-Chih Tsai 1, 2, C. H. Liu 3, T. Y. Hsiao 4, and J. Y. Huang 1 (1) Center for Space and Remote Sensing research,
More informationImpact of the low latitude ionosphere disturbances on GNSS studied with a three-dimensional ionosphere model
Impact of the low latitude ionosphere disturbances on GNSS studied with a three-dimensional ionosphere model Susumu Saito and Naoki Fujii Communication, Navigation, and Surveillance Department, Electronic
More informationIonospheric Estimation using Extended Kriging for a low latitude SBAS
Ionospheric Estimation using Extended Kriging for a low latitude SBAS Juan Blanch, odd Walter, Per Enge, Stanford University ABSRAC he ionosphere causes the most difficult error to mitigate in Satellite
More informationRadio Astronomy and the Ionosphere
Radio Astronomy and the Ionosphere John A Kennewell, Mike Terkildsen CAASTRO EoR Global Signal Workshop November 2012 THE IONOSPHERE UPPER ATMOSPHERIC PLASMA - The ionosphere is a weak (1%) variable plasma
More informationThe GPS measured SITEC caused by the very intense solar flare on July 14, 2000
Advances in Space Research 36 (2005) 2465 2469 www.elsevier.com/locate/asr The GPS measured SITEC caused by the very intense solar flare on July 14, 2000 Weixing Wan a, *, Libo Liu a, Hong Yuan b, Baiqi
More informationForeword by Glen Gibbons About this book Acknowledgments List of abbreviations and acronyms List of definitions
Table of Foreword by Glen Gibbons About this book Acknowledgments List of abbreviations and acronyms List of definitions page xiii xix xx xxi xxv Part I GNSS: orbits, signals, and methods 1 GNSS ground
More information