scholarly journals The influence of geomagnetic storms on the estimation of GPS instrumental biases

2009 ◽  
Vol 27 (4) ◽  
pp. 1613-1623 ◽  
Author(s):  
W. Zhang ◽  
D. H. Zhang ◽  
Z. Xiao
Keyword(s):  
Global Positioning System ◽  
Geomagnetic Storms ◽  
Critical Factor ◽  
Electron Content ◽  
Storm Events ◽  
Ionospheric Storm ◽  
Total Electron ◽  
Gps Satellites ◽  
Global Positioning ◽  
Single Receiver

Abstract. An algorithm has been developed to derive the ionospheric total electron content (TEC) and to estimate the resulting instrumental biases in Global Positioning System (GPS) data from measurements made with a single receiver. The algorithm assumes that the TEC is identical at any point within a mesh and that the GPS instrumental biases do not vary within a day. We present some results obtained using the algorithm and a study of the characteristics of the instrumental biases during active geomagnetic periods. The deviations of the TEC during an ionospheric storm (induced by a geomagnetic storm), compared to the quiet ionosphere, typically result in severe fluctuations in the derived GPS instrumental biases. Based on the analysis of three ionospheric storm events, we conclude that different kinds of ionospheric storms have differing influences on the measured biases of GPS satellites and receivers. We find that the duration of severe ionospheric storms is the critical factor that adversely impacts the estimation of GPS instrumental biases. Large deviations in the TEC can produce inaccuracies in the estimation of GPS instrumental biases for the satellites that pass over the receiver during that period. We also present a semi quantitative analysis of the duration of the influence of the storm.

scholarly journals Comparative Study of the Influence of Full and Partial Halo Geomagnetic Storms on High Latitude Ionosphere

2021 ◽  
Vol 4 (2) ◽  
pp. 41-52
Author(s):  
Dominic Chukwuebuka Obiegbuna ◽  
Francisca Nneka Okeke ◽  
Kingsley Chukwudi Okpala ◽  
Orji Prince Orji ◽  
Gregory Ibeabuchi Egba ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Global Positioning System ◽  
High Latitude ◽  
Geomagnetic Storms ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Global Positioning ◽  
High Latitude Ionosphere ◽  
Gnss Observations

We have studied and compared the effects of full and partial halo geomagnetic storms on the high latitude ionosphere. The study used the total electron content (TEC) data obtained from the global positioning system (GPS) to examine the level of response of high latitude ionosphere around Ny Alesund, Norway to full and partial halo geomagnetic storms of June 23rd 2015 and January 1st 2016 respectively. This study was carried out using a dual frequency ground based GNSS observations at high latitude (NYAL: 78.56oN, 11.52oE) ionospheric station in Norway. The vertical TEC (VTEC) was extracted from Receiver Independent Exchange (RINEX) formatted GPS-TEC data using the GOPI Software developed by Seemala Gopi. The GOPI software is a GNSS-TEC analysis program which uses ephemeris data and differential code biases (DCBs) in estimating slant TEC (STEC) prior to its conversion to VTEC. From the results, the responses of the high latitude before the storm days were more positive than on the storm days. Also the overall response of the high latitude to the full halo geomagnetic storm was more positive with more impact than that of the partial halo geomagnetic storm.

scholarly journals Comparison of GPS TEC with IRI models of 2007, 2012, AND 1 2016 over Sukkur, Pakistan

2020 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Adil Hussain ◽  
Munawar Shah
Keyword(s):  
Global Positioning System ◽  
Electron Content ◽  
Iri Model ◽  
Low Latitude ◽  
Total Electron ◽  
Gps Tec ◽  
Global Positioning ◽  
Radio Signals ◽  
Ionospheric Scintillations ◽  
Latitude Region

The international reference ionosphere (IRI) models have been widely used for correcting the ionospheric scintillations at different altitude levels. An evaluation on the performance of VTEC correction from IRI models (version 2007, 2012 and 2016) over Sukkur, Pakistan (27.71º N, 68.85º E) is presented in this work. Total Electron Content (TEC) from IRI models and GPS in 2019 over Sukkur region are compared. The main aim of this comparative analysis is to improve the VTEC in low latitude Sukkur, Pakistan. Moreover, this study will also help us to identify the credible IRI model for the correction of Global Positioning System (GPS) signal in low latitude region in future. The development of more accurate TEC finds useful applications in enhancing the extent to which ionospheric influences on radio signals are corrected. VTEC from GPS and IRI models are collected between May 1, 2019 and May 3, 2019. Additionally, Dst and Kp data are also compared in this work to estimate the geomagnetic storm variations. This study shows a good correlation of 0.83 between VTEC of GPS and IRI 2016. Furthermore, a correlation of 0.82 and 0.78 is also recorded for IRI 2012 and IRI 2007 respectively, with VTEC of GPS. The IRI TEC predictions and GPS-TEC measurements for the studied days reveal the potential of IRI model as a good candidate over Pakistan.

Variability of GPS-derived Ionospheric TEC over Nigeria during a year of low solar activity

2020 ◽  
Author(s):  
G.A. Akinyemi ◽  
L.B. Kolawole ◽  
O.F. Dairo ◽  
Alexander A. Willoughby ◽  
R.B. Abdulrahim ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Electron Content ◽  
Gps Receiver ◽  
Total Electron ◽  
Ionospheric Total Electron Content ◽  
Global Positioning ◽  
Variability Index ◽  
Gnss Network ◽  
Tec Variability ◽  
Anomaly Region

An investigation on the diurnal and seasonal variability of ionospheric Total Electron Content (TEC) over Nigeria is carried out in this study using Global Positioning System (GPS) observable. Nigeria coordinates fall within the trough of equatorial ionization anomaly region of African sector. The TEC data used were obtained from the ground-based GPS receiver stations of the Nigerian GNSS network of stations (NIGNET). The stations with their respective geomagnetic latitudes are Abuja (−1.64º), Yola (−1.32º), Zaria (−0.13º) and Kebbi (0.72º). The results of the diurnal analysis of the relative variability index (VD) revealed higher nighttime values than daytime values. The diurnal variation of VD also showed two conspicuous peaks: the post-midnight and the post-sunset. The diurnal-seasonal variation does not reveal any consistent pattern (no particular season leads the others throughout). On the average, considering all the seasons together maximum TEC variability occurred in Zaria (62%) and least in Yola (54%). Seasonally, maximum VD was recorded during March equinox and the least was recorded during December equinox.

scholarly journals Pre-earthquake ionospheric anomalies registered by continuous GPS TEC measurements

2004 ◽  
Vol 22 (5) ◽  
pp. 1585-1593 ◽  
Author(s):  
J. Y. Liu ◽  
Y. J. Chuo ◽  
S. J. Shan ◽  
Y. B. Tsai ◽  
Y. I. Chen ◽  
...  
Keyword(s):  
Key Words ◽  
Global Positioning System ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Positioning System ◽  
Total Electron ◽  
Gps Tec ◽  
Global Positioning ◽  
Continuous Gps ◽  
Large Earthquakes

Abstract. In this paper we examine pre-earthquake ionospheric anomalies by the total electron content (TEC) derived from a ground-based receiver of the Global Positioning System (GPS). A 15-day running median of the TEC and the associated inter-quartile range (IQR) are utilized as a reference for identifying abnormal signals during all of the 20M≥6.0 earthquakes in the Taiwan area from September 1999 to December 2002. Results show that the pre-earthquake ionospheric anomalies appear during 18:00–22:00LT (LT=UT+8h) within 5 days prior to 16 of the 20M≥6.0 earthquakes. This success rate of 80% (=16/20%) suggests that the GPS TEC is useful to register pre-earthquake ionospheric anomalies appearing before large earthquakes. Key words. Ionosphere (ionospheric disturbances; ionosphere-atmosphere interactions)

scholarly journals Study of ionospheric disturbances over the China mid- and low-latitude region with GPS observations

2018 ◽  
Vol 36 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Yafei Ning ◽  
Jun Tang
Keyword(s):  
Global Positioning System ◽  
Electron Content ◽  
Ionospheric Disturbances ◽  
Differential Rate ◽  
Low Latitude ◽  
Total Electron ◽  
Ionospheric Variability ◽  
Global Positioning ◽  
Latitude Region ◽  
Gps Observations

Abstract. Ionospheric disturbances constitute the main restriction factor for precise positioning techniques based on global positioning system (GPS) measurements. Simultaneously, GPS observations are widely used to determine ionospheric disturbances with total electron content (TEC). In this paper, we present an analysis of ionospheric disturbances over China mid- and low-latitude area before and during the magnetic storm on 17 March 2015. The work analyses the variation of magnetic indices, the amplitude of ionospheric irregularities observed with four arrays of GPS stations and the influence of geomagnetic storm on GPS positioning. The results show that significant ionospheric TEC disturbances occurred between 10:30 and 12:00 UT during the main phase of the large storm, and the static position reliability for this period are little affected by these disturbances. It is observed that the positive and negative disturbances propagate southward along the meridian from mid-latitude to low-latitude regions. The propagation velocity is from about 200 to 700 m s−1 and the amplitude of ionospheric disturbances is from about 0.2 to 0.9 TECU min−1. Moreover, the position dilution of precession (PDOP) with static precise point positioning (PPP) on storm and quiet days is 1.8 and 0.9 cm, respectively. This study is based on the analysis of ionospheric variability with differential rate of vertical TEC (DROVT) and impact of ionospheric storm on positioning with technique of GPS PPP. Keywords. Ionosphere (ionospheric disturbances)

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