The effect of ionospheric delay on the ground-based augmentation system under normal conditions can be mitigated by determining the value of the nominal ionospheric gradient(σvig).The nominal ionospheric gradient is ...The effect of ionospheric delay on the ground-based augmentation system under normal conditions can be mitigated by determining the value of the nominal ionospheric gradient(σvig).The nominal ionospheric gradient is generally obtained from Continuously Operating Reference Stations data by using the spatial single-difference method(mixed-pair,station-pair,or satellite-pair)or the temporal single-difference method(time-step).The time-step method uses only a single receiver,but it still contains ionospheric temporal variations.We introduce a corrected time-step method using a fixed-ionospheric pierce point from the geostationary equatorial orbit satellite and test it through simulations based on the global ionospheric model.We also investigate the effect of satellite paths on the corrected time-step method in the region of the equator,which tends to be in a more north–south direction and to have less coverage for the east–west ionospheric gradient.This study also addresses the limitations of temporal variation correction coverage and recommends using only the correction from self-observations.All processes are developed under simulations because observational data are still difficult to obtain.Our findings demonstrate that the corrected time-step method yieldsσvig values consistent with other approaches.展开更多
The electron concentration horizontal gradient vector of the ionosphere and its south-north and east-west components over Chongqing station are analyzed and calculated, using the first approximation, time correlation ...The electron concentration horizontal gradient vector of the ionosphere and its south-north and east-west components over Chongqing station are analyzed and calculated, using the first approximation, time correlation and space correlation and another approach introduced. And then, the validity of the two methods is analyzed and compared.展开更多
Detecting and characterizing Total Electron Content(TEC)depletion is important for studying the ionospheric threat due to the Equatorial Plasma Bubble(EPB)when applying the Ground-Based Augmentation System(GBAS)at low...Detecting and characterizing Total Electron Content(TEC)depletion is important for studying the ionospheric threat due to the Equatorial Plasma Bubble(EPB)when applying the Ground-Based Augmentation System(GBAS)at low latitudes.This paper develops a robust method to automatically identify TEC depletion and derive its parameters.The rolling barrel algorithm is used to automatically identify the TEC depletion candidate and its parameters.Then,the depletion candidates are screened by several improved techniques to distinguish actual depletions from other phenomena such as Traveling Ionospheric Disturbance(TID)or abnormal data.Next,based on the depletion signals from three triangular receivers,the method derives EPB parameters such as velocity,width and gradient.The time lag and front velocity are calculated based on crosscorrelation using TEC depletions and the geometrical distribution of three triangular receivers.The width and gradient of slope are then determined by using TEC depletion from a single receiver.By comparison,both the station-pair method and proposed method depend on the assumption that the EPB morphology is frozen during the short time when the plasma bubble moves between the receivers.However,our method relaxes the restriction that the baseline length should be shorter than the width of slope required by the station-pair.This relaxation is favorable for studying small-scale slope of depletions using stations of a longer baseline.In addition,the accuracy of the width and gradient is free of impact from hardware biases and small-scale disturbance,as it is based only on the relative TEC variation.The method is demonstrated by processing Global Positioning System(GPS)and Bei Dou Navigation Satellite System(BDS)data on 15 August,2018,in a solar minimum cycle.展开更多
基金funding from BRIN through the Research Collaboration Program with ORPA(No.2/III.1/HK/2024)Prayitno Abadi is participating in this study as part of a Memorandum of Understanding for Research Collaboration on Regional Ionospheric Observation at Telkom University(No.092/SAM3/TE-DEK/2021).
文摘The effect of ionospheric delay on the ground-based augmentation system under normal conditions can be mitigated by determining the value of the nominal ionospheric gradient(σvig).The nominal ionospheric gradient is generally obtained from Continuously Operating Reference Stations data by using the spatial single-difference method(mixed-pair,station-pair,or satellite-pair)or the temporal single-difference method(time-step).The time-step method uses only a single receiver,but it still contains ionospheric temporal variations.We introduce a corrected time-step method using a fixed-ionospheric pierce point from the geostationary equatorial orbit satellite and test it through simulations based on the global ionospheric model.We also investigate the effect of satellite paths on the corrected time-step method in the region of the equator,which tends to be in a more north–south direction and to have less coverage for the east–west ionospheric gradient.This study also addresses the limitations of temporal variation correction coverage and recommends using only the correction from self-observations.All processes are developed under simulations because observational data are still difficult to obtain.Our findings demonstrate that the corrected time-step method yieldsσvig values consistent with other approaches.
基金Supported by the National Natural Science Foundation of China(6 95 710 2 0 ) and the Research Fund for the Doctoral Program of H
文摘The electron concentration horizontal gradient vector of the ionosphere and its south-north and east-west components over Chongqing station are analyzed and calculated, using the first approximation, time correlation and space correlation and another approach introduced. And then, the validity of the two methods is analyzed and compared.
基金financial support from National Key Research and Development Program of China(No.2017YFB0503404)the National Natural Science Foundation of China(Nos.61871012,U1833125)+2 种基金Open fund project of Intelligent Operation Key Laboratory of Civil Aviation Airport Group(No.KLAGIO20180405)The National Key Research and Development Program of China(No.2018YFB0505105)Beijing Nova Program of Science and Technology(No.Z191100001119134)。
文摘Detecting and characterizing Total Electron Content(TEC)depletion is important for studying the ionospheric threat due to the Equatorial Plasma Bubble(EPB)when applying the Ground-Based Augmentation System(GBAS)at low latitudes.This paper develops a robust method to automatically identify TEC depletion and derive its parameters.The rolling barrel algorithm is used to automatically identify the TEC depletion candidate and its parameters.Then,the depletion candidates are screened by several improved techniques to distinguish actual depletions from other phenomena such as Traveling Ionospheric Disturbance(TID)or abnormal data.Next,based on the depletion signals from three triangular receivers,the method derives EPB parameters such as velocity,width and gradient.The time lag and front velocity are calculated based on crosscorrelation using TEC depletions and the geometrical distribution of three triangular receivers.The width and gradient of slope are then determined by using TEC depletion from a single receiver.By comparison,both the station-pair method and proposed method depend on the assumption that the EPB morphology is frozen during the short time when the plasma bubble moves between the receivers.However,our method relaxes the restriction that the baseline length should be shorter than the width of slope required by the station-pair.This relaxation is favorable for studying small-scale slope of depletions using stations of a longer baseline.In addition,the accuracy of the width and gradient is free of impact from hardware biases and small-scale disturbance,as it is based only on the relative TEC variation.The method is demonstrated by processing Global Positioning System(GPS)and Bei Dou Navigation Satellite System(BDS)data on 15 August,2018,in a solar minimum cycle.
