Centre dedocumentation
scientifique

On-orbit BDS signals and transmit antenna gain analysis for a geostationary satellite / Meng Wang in Advances in space research, vol 69 n° 7 (April 2022)  

Public [article]  inAdvances in space research > vol 69 n° 7 (April 2022) . - pp 2711 - 2723 Titre : On-orbit BDS signals and transmit antenna gain analysis for a geostationary satellite Type de document : Article/Communication Auteurs : Meng Wang, Auteur ; Tao Shan, Auteur ; Lei Liu, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 2711 - 2723 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes IGN] affaiblissement de la précision [Termes IGN] orbite géostationnaire [Termes IGN] orbite terrestre [Termes IGN] orbitographie [Termes IGN] récepteur BeiDou [Termes IGN] satellite géostationnaire [Termes IGN] signal BeiDou Résumé : (auteur) A Beidou navigation satellite system (BDS) receiver with high sensitivity is embarked in a geostationary orbit (GEO) spacecraft to demonstrate characteristics of BDS signals tracked. This receiver can be compatible with the regional (BDS-2) and global (BDS-3) systems, which have three orbit types: medium Earth orbit (MEO), inclined geostationary orbit (IGSO), and GEO. The on-orbit BDS signal characteristics, including observations quantity, availability, position dilution of precision (PDOP), and carrier-to-noise ratio (C/N0), are presented according to in-flight data. The observations and distribution of C/N0 with respect to nadir angles were analyzed. The average number of the BDS satellites tracked is 4.4, and the average PDOP is 12.0. PDOP improves when the BDS GEO and IGSO observations are involved. The maximum value of C/N0 of the BDS-3 MEO satellites is approximately 49 dB-Hz, which is roughly 2 dB higher than that of the BDS-2 MEO satellites. Most of the C/N0 of the BDS-3 MEO satellite at nadir angles beyond 26° is in the range of 27–34 dB-Hz. We reconstruct the transmit antenna gain for all observed BDS satellites using C/N0 measurements. Moreover, we investigate the main and side lobe characteristics of the BDS satellites in terms of different orbit types and satellite manufacturers. The side lobe signals of the BDS-3 MEO generally have 20–30 dB lower gain than the peak main lobe gain. The side lobe signal performance of the BDS-2 MEO is evidently better than that of the BDS-3 MEO. We give side lobe characteristics analysis of the BDS-3 MEO satellites from two different manufacturers based on the transmit antenna gain reconstructed. Numéro de notice : A2022-230 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1016/j.asr.2022.01.022 Date de publication en ligne : 25/01/2022 En ligne : https://doi.org/10.1016/j.asr.2022.01.022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100107 [article]

A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance / Jian Kong in Journal of geodesy, vol 90 n° 8 (August 2016)  

Public [article]  inJournal of geodesy > vol 90 n° 8 (August 2016) . - pp 741 – 755 Titre : A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance Type de document : Article/Communication Auteurs : Jian Kong, Auteur ; Yi Bin Yao, Auteur ; Lei Liu, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 741 – 755 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] altération [Termes IGN] correction troposphérique [Termes IGN] International Reference Ionosphere [Termes IGN] Japon [Termes IGN] séisme [Termes IGN] teneur totale en électrons [Termes IGN] tomographie [Termes IGN] troposphère Résumé : (auteur) A new algorithm for ionosphere tomography using the mapping function is proposed in this paper. First, the new solution splits the integration process into four layers along the observation ray, and then, the single-layer model (SLM) is applied to each integration part using a mapping function. Next, the model parameters are estimated layer by layer with the Kalman filtering method by introducing the scale factor (SF) γ to solve the ill-posed problem. Finally, the inversed images of different layers are combined into the final CIT image. We utilized simulated data from 23 IGS GPS stations around Europe to verify the estimation accuracy of the new algorithm; the results show that the new CIT model has better accuracy than the SLM in dense data areas and the CIT residuals are more closely grouped. The stability of the new algorithm is discussed by analyzing model accuracy under different error levels (the max errors are 5TECU, 10TECU, 15TECU, respectively). In addition, the key preset parameter, SFγ, which is given by the International Reference Ionosphere model (IRI2012). The experiment is designed to test the sensitivity of the new algorithm to SF variations. The results show that the IRI2012 is capable of providing initial SF values. Also in this paper, the seismic-ionosphere disturbance (SID) of the 2011 Japan earthquake is studied using the new CIT algorithm. Combined with the TEC time sequence of Sat.15, we find that the SID occurrence time and reaction area are highly related to the main shock time and epicenter. According to CIT images, there is a clear vertical electron density upward movement (from the 150-km layer to the 450-km layer) during this SID event; however, the peak value areas in the different layers were different, which means that the horizontal movement velocity is not consistent among the layers. The potential physical triggering mechanism is also discussed in this paper. Compared with the SLM, the RMS of the new CIT model is improved by 16.78%, while the CIT model could provide the three-dimensional variation in the ionosphere. Numéro de notice : A2016-504 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0906-9 En ligne : http://dx.doi.org/10.1007/s00190-016-0906-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81528 [article]