scholarly journals Comparisons of ionospheric total electron contents made at Boulder, Colorado, using the Global Positioning System

Radio Science ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 1491-1497 ◽  
Author(s):  
Raymond O. Conkright ◽  
Kenneth Davies ◽  
Steven Musman
Keyword(s):  
Global Positioning System ◽  
Positioning System ◽  
Total Electron ◽  
Global Positioning ◽  
Total Electron Contents ◽  
Ionospheric Total Electron Contents

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 GPS-TEC observations over Nepal during the Total Solar Eclipse on 22 July 2009

2021 ◽  
Vol 7 (1) ◽  
pp. 54-59
Author(s):  
A. N. Shrestha ◽  
Y. Migoya-Orue
Keyword(s):  
Global Positioning System ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Electron Content ◽  
Positioning System ◽  
Total Electron ◽  
Ionospheric Response ◽  
Gps Tec ◽  
Global Positioning ◽  
Geographical Locations

This paper explores the ionospheric response in terms of Total Electron Content (TEC) during the 22 July 2009 Total Solar Eclipse. Using the data stored at Biratnagar (BRN2), Ramite (RMTE), Dhangadhi (DNGD), Nepalganj (NPGJ), and Taplejung (TPLJ) Global Positioning System (GPS) stations, the ionospheric activity was investigated through changes in TEC. Our research is based on GPS-TEC measurements from a widely dispersed GPS network across various geographical locations in Nepal, taking place on July 17-21 as a pre-event, July 22 as the main event, and July 23-27 as a post-event. The analysis reveals that the reduction in the TEC level is proportional to the magnitude of the total solar eclipse. The variation of the TEC depends on latitude as well as longitude. We found that TEC depletion was up to 5% from pre-event to main-event and up to 30% from main-event to post-event during the totality of the eclipse. The eclipse was accompanied by the 10-hour geomagnetic storm in Nepal, which was the explanation for the TEC upgrade to 50% on the main event day from pre-event and decreased by 25% from main-event to post-event. The result obtained in this work demonstrates the influence of the eclipse/storm on the variation of TEC.

scholarly journals Estimating satellite and receiver differential code bias using a relative Global Positioning System network

2019 ◽  
Vol 37 (6) ◽  
pp. 1039-1047 ◽  
Author(s):  
Alaa A. Elghazouly ◽  
Mohamed I. Doma ◽  
Ahmed A. Sedeek
Keyword(s):  
Least Squares ◽  
Global Positioning System ◽  
Gps Data ◽  
Electron Content ◽  
Positioning System ◽  
Total Electron ◽  
Gps Network ◽  
Global Positioning ◽  
The Mean ◽  
Mean Differences

Abstract. Precise total electron content (TEC) is required to produce accurate spatial and temporal resolution of global ionosphere maps (GIMs). Receivers and satellite differential code biases (DCBs) are one of the main error sources in estimating precise TEC from Global Positioning System (GPS) data. Recently, researchers have been interested in developing models and algorithms to compute DCBs of receivers and satellites close to those computed from the Ionosphere Associated Analysis Centers (IAACs). Here we introduce a MATLAB code called Multi Station DCB Estimation (MSDCBE) to calculate satellite and receiver DCBs from GPS data. MSDCBE based on a spherical harmonic function and a geometry-free combination of GPS carrier-phase, pseudo-range code observations, and weighted least squares was applied to solve observation equations and to improve estimation of DCB values. There are many factors affecting the estimated values of DCBs. The first one is the observation weighting function which depends on the satellite elevation angle. The second factor is concerned with estimating DCBs using a single GPS station using the Zero Difference DCB Estimation (ZDDCBE) code or using the GPS network used by the MSDCBE code. The third factor is the number of GPS receivers in the network. Results from MSDCBE were evaluated and compared with data from IAACs and other codes like M_DCB and ZDDCBE. The results of weighted (MSDCBE) least squares show an improvement for estimated DCBs, where mean differences from the Center for Orbit Determination in Europe (CODE) (University of Bern, Switzerland) are less than 0.746 ns. DCBs estimated from the GPS network show better agreement with IAAC than DCBs estimated from precise point positioning (PPP), where the mean differences are less than 0.1477 and 1.1866 ns, respectively. The mean differences of computed DCBs improved by increasing the number of GPS stations in the network.

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