scholarly journals Registration of ionospheric effect of 20 March 2015 solar eclipse from GPS data in single-frequency mode

2015 ◽  
Vol 1 (4) ◽  
pp. 35-39 ◽  
Author(s):  
Олег Горбачев ◽  
Oleg Gorbachev ◽  
Всеволод Иванов ◽  
Vsevolod Ivanov ◽  
Андрей Холмогоров ◽  
...  
Keyword(s):  
Solar Eclipse ◽  
Quantitative Agreement ◽  
Single Frequency ◽  
Gps Data ◽  
Electron Content ◽  
Time Behavior ◽  
Dual Frequency ◽  
Total Electron ◽  
Appropriate Treatment ◽  
Time Courses

The paper objective is to demonstrate the possibility of studying irregular variations of the total electron content (TEC) of the ionosphere using GPS data of single-frequency measurements. This is considered by the example of registering the time behavior of the oblique TEC during the 20 March 2015 solar eclipse. As the initial data, we used single-frequency and dual-frequency phase and code measurements from the station MORP which is a part of the International IGS Network. As a result, by comparing the data of TEC time courses for two modes it is shown both qualitative agreement (TEC significant decrease during the eclipse) and quantitative agreement of results after appropriate treatment.

scholarly journals Functional model modification of precise point positioning considering the time-varying code biases of a receiver

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Baocheng Zhang ◽  
Chuanbao Zhao ◽  
Robert Odolinski ◽  
Teng Liu
Keyword(s):  
Precise Point Positioning ◽  
Functional Model ◽  
Geodetic Network ◽  
Temporal Variations ◽  
Gps Data ◽  
Electron Content ◽  
Time Varying ◽  
Dual Frequency ◽  
Total Electron ◽  
Point Positioning

AbstractPrecise Point Positioning (PPP), initially developed for the analysis of the Global Positing System (GPS) data from a large geodetic network, gradually becomes an effective tool for positioning, timing, remote sensing of atmospheric water vapor, and monitoring of Earth’s ionospheric Total Electron Content (TEC). The previous studies implicitly assumed that the receiver code biases stay constant over time in formulating the functional model of PPP. In this contribution, it is shown this assumption is not always valid and can lead to the degradation of PPP performance, especially for Slant TEC (STEC) retrieval and timing. For this reason, the PPP functional model is modified by taking into account the time-varying receiver code biases of the two frequencies. It is different from the Modified Carrier-to-Code Leveling (MCCL) method which can only obtain the variations of Receiver Differential Code Biases (RDCBs), i.e., the difference between the two frequencies’ code biases. In the Modified PPP (MPPP) model, the temporal variations of the receiver code biases become estimable and their adverse impacts on PPP parameters, such as ambiguity parameters, receiver clock offsets, and ionospheric delays, are mitigated. This is confirmed by undertaking numerical tests based on the real dual-frequency GPS data from a set of global continuously operating reference stations. The results imply that the variations of receiver code biases exhibit a correlation with the ambient temperature. With the modified functional model, an improvement by 42% to 96% is achieved in the Differences of STEC (DSTEC) compared to the original PPP model with regard to the reference values of those derived from the Geometry-Free (GF) carrier phase observations. The medium and long term (1 × 104 to 1.5 × 104 s) frequency stability of receiver clocks are also significantly improved.

scholarly journals Analysis of Total Electron Content (TEC) Near Real Time Using Dual Frequency GPS Data (Study Case: Surabaya)

2019 ◽  
Vol 94 ◽  
pp. 05005 ◽  
Author(s):  
Mokhamad Nur Cahyadi ◽  
Almas Nandityo Rahadyan ◽  
Buldan Muslim
Keyword(s):  
Total Electron Content ◽  
Electromagnetic Waves ◽  
Signal Propagation ◽  
Gps Data ◽  
Electron Content ◽  
Dual Frequency ◽  
Additional Time ◽  
Ionospheric Correction ◽  
Total Electron ◽  
A Value

Ionosphere is part of the atmospheric layer located between 50 to 1000 km above the earth's surface which consists of electrons that can influence the propagation of electromagnetic waves in the form of additional time in signal propagation, this depends on Total Electron Content (TEC) in the ionosphere and frequency GPS signal. In high positioning precision with GPS, the effect of the ionosphere must be estimated so that ionospheric correction can be determined to eliminate the influence of the ionosphere on GPS observation. Determination of ionospheric correction can be done by calculating the TEC value using dual frequency GPS data from reference stations or models. In making the TEC model, a polynomial function is used for certain hours. The processing results show that the maximum TEC value occurs at noon at 2:00 p.m. WIB for February 13, 2018 with a value of 35,510 TECU and the minimum TEC value occurs in the morning at 05.00 WIB for February 7, 2018 with a value of 2,138 TECU. The TEC model spatially shows the red color in the area of Surabaya and its surroundings for the highest TEC values during the day around 13.00 WIB to 16.00 WIB.

Performance Evaluation of USTEC Product for Single-Frequency Precise Point Positioning

GEOMATICA ◽  
2013 ◽  
Vol 67 (4) ◽  
pp. 253-257 ◽  
Author(s):  
Mahmoud Abd El-Rahman ◽  
Ahmed El-Rabbany
Keyword(s):  
Total Electron Content ◽  
Precise Point Positioning ◽  
Ionospheric Delay ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Gps Receivers ◽  
Mitigation Techniques ◽  
Point Positioning

Geodetic-grade dual-frequency GPS receivers are typically used for precise point positioning (PPP). Unfortunately, these receiver systems are expensive and may not provide a cost-effective solution in many instances. The use of low-cost single-frequency GPS receivers, on the other hand, are limited by the effect of ionospheric delay. A number of mitigation techniques have been proposed to account for the effect of ionospheric delay for single-frequency GPS users. Unfortunately, however, those mitigation techniques are not suitable for PPP. More recently, the U.S. Total Electron Content (USTEC) product has been developed by the National Oceanic and Atmospheric Administration (NOAA), which describes the ionospheric total electron content in high resolution over most of North America. This paper investigates the performance of USTEC and studies its effect on single-frequency PPP solution. A performance comparison with two widely-used ionospheric mitigation models is also presented.

scholarly journals Deep learning of total electron content

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Omid Memarian Sorkhabi
Keyword(s):  
Deep Learning ◽  
Total Electron Content ◽  
Single Layer ◽  
Activation Function ◽  
Satellite System ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Global Navigation Satellite

AbstractOne of the most notable errors in the global navigation satellite system (GNSS) is the ionospheric delay due to the total electron content (TEC). TEC is the number of electrons in the ionosphere in the signal path from the satellite to the receiver, which fluctuates with time and location. This error is one of the major problems in single-frequency (SF) GPS receivers. One way to eliminate this error is to use dual-frequency. Users of SF receivers should either use estimation models or local models to reduce this error. In this study, deep learning of artificial neural networks (ANN) was used to estimate TEC for SF users. For this purpose, the ionosphere as a single-layer model (assuming that all free electrons in the ionosphere are in this thin layer) is locally modeled by the code observation method. Linear combination has been used by selecting 24 permanent GNSS stations in the northwest of Iran. TEC was modeled independently of the geometry between the satellite and the receiver, called L4. This modeling was used to train the error ANN with two 5-day periods of high and low solar and geomagnetic activity range with a hyperbolic tangential sigmoid activation function. The results show that the proposed method is capable of eliminating ionosphere error with an average accuracy of 90%. The international reference ionosphere 2016 (IRI2016) is used for the verification, which has a 96% significance correlation with estimated TEC.

scholarly journals Galileo E5 AltBOC Signals: Application for Single-Frequency Total Electron Content Estimations

2021 ◽  
Vol 13 (19) ◽  
pp. 3973
Author(s):  
Artem M. Padokhin ◽  
Anna A. Mylnikova ◽  
Yury V. Yasyukevich ◽  
Yury V. Morozov ◽  
Gregory A. Kurbatov ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Noise Level ◽  
Satellite System ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Binary Offset Carrier ◽  
Total Electron ◽  
Galileo E5 ◽  
Global Navigation Satellite

Global navigation satellite system signals are known to be an efficient tool to monitor the Earth ionosphere. We suggest Galileo E5 AltBOC phase and pseudorange observables— a single-frequency combination—to estimate the ionospheric total electron content (TEC). We performed a one-month campaign in September 2020 to compare the noise level for different TEC estimations based on single-frequency and dual-frequency data. Unlike GPS, GLONASS, or Galileo E5a and E5b single-frequency TEC estimations (involving signals with binary and quadrature phase-shift keying, such as BPSK and QPSK, or binary offset carrier (BOC) modulation), an extra wideband Galileo E5 AltBOC signal provided the smallest noise level, comparable to that of dual-frequency GPS. For elevation higher than 60 degrees, the 100-sec root-mean-square (RMS) of TEC, an estimated TEC noise proxy, was as follows for different signals: ~0.05 TECU for Galileo E5 AltBOC, 0.09 TECU for GPS L5, ~0.1TECU for Galileo E5a/E5b BPSK, and 0.85 TECU for Galileo E1 CBOC. Dual-frequency phase combinations provided RMS values of 0.03 TECU for Galileo E1/E5, 0.03 and 0.07 TECU for GPS L1/L2 and L1/L5. At low elevations, E5 AltBOC provided at least twice less single-frequency TEC noise as compared with data obtained from E5a or E5b. The short dataset of our study could limit the obtained estimates; however, we expect that the AltBOC single-frequency TEC will still surpass the BPSK analogue in noise parameters when the solar cycle evolves and geomagnetic activity increases. Therefore, AltBOC signals could advance geoscience.

scholarly journals Analysis of Tec Variations over Nepal Obtained from GPS Data on Geo-Magnetically Quiet and Disturbed Days of the Year 2015

2021 ◽  
Vol 7 (2) ◽  
pp. 102-109
Author(s):  
B. D. Ghimire ◽  
N. P. Chapagain ◽  
V. Basnet ◽  
B. Khadka
Keyword(s):  
Weather Prediction ◽  
Vapor Concentration ◽  
Gps Data ◽  
Electron Content ◽  
Gps Receiver ◽  
Dual Frequency ◽  
Total Electron ◽  
Gps Tec ◽  
Global Positioning ◽  
The Difference

Dual frequency Global Positioning System (GPS) receiver in two nearby stations i.e. BESI (28.228 °N, 84.739 °E) and GHER (28.375 °N, 84.739 °E) located at almost same latitude and longitude are used to measure ionospheric total electron content (TEC) for the year 2015. Since Year of 2014- 2016 have been known as most active years in terms of geomagnetic events, the year 2015 shows some abnormal results. Diurnal, monthly and seasonal variations of GPS TEC have been studied. The difference in the value of TEC is observed between quiet and disturbed days. Moreover, the correlation between GPS-data of each month with solar activities parameters such as Kp index, disturbance storm time (Dst) index, and Solar Flux index (F10.7 cm) have been studied, separately for quiet and disturbed days for each station. In case of diurnal variation, mean TEC varies from 0100 UT (LT= UT+5:45) to maximum from 0900 UT to 1100UT. The value of TEC is observed higher on quiet days than disturbed days. For seasonal variation, local seasons i.e. autumn, Spring, Summer and Winter is taken and, the value of TEC is found to be higher in Spring (March, April and May) in both stations in quiet and disturbed days. The difference in value of quiet and disturbed days of GPS-TEC explained the geomagnetic phenomena difference in these days in ionosphere. This study can be useful to calculate the water vapor concentration in the atmosphere which is useful for weather prediction and meteorological department.

scholarly journals Tracking the Ionospheric Response to the Solar Eclipse of November 03, 2013

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Emirant Bertillas Amabayo ◽  
Simon Katrini Anguma ◽  
Edward Jurua
Keyword(s):  
Solar Radiation ◽  
Solar Eclipse ◽  
Maximum Amplitude ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Perturbation Amplitude ◽  
Global Positioning ◽  
Energy And Momentum ◽  
Ionospheric Dynamics

The ionospheric dynamics is highly influenced by the solar radiation. During a solar eclipse, the moon occults the solar radiation from reaching the ionosphere, which may drastically affect the variability of the ionosphere. The variability of total electron content (TEC) observed by dual frequency Global Positioning System (GPS) receivers has made it possible to study effects of solar eclipse on the ionosphere. Total eclipse occurred on November 03, 2013, and the maximum amplitude was visible at Owiny in northern Uganda. Ionospheric behavior during this eclipse was analysed by using TEC data archived at Mbarara (MBAR), Malindi (MAL2), Eldoret (MOIU), and Kigali University (NURK) International GPS Satellite (IGS) stations. TEC variations of four consecutive days were used to study instantaneous changes of TEC during the eclipse event. The results generally show TEC decrease at the four stations. However, a maximum perturbation amplitude of ≥20 TECU was observed at MAL2 (18:00–20:00 UT) which is further south of the equator than the other stations. TEC enhancement and depletion were observed during the totality of the eclipse at MOIU, MBAR, NURK, and MAL2 (13:00–15:00 UT). This study found out that the ionospheric TEC over East Africa was modified by wave-like energy and momentum transport and obscuration of the solar disc due to the total solar eclipse.

scholarly journals Adjusting CCIR Maps to Improve Local Behaviour of Ionospheric Models

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 691
Author(s):  
Haris Haralambous ◽  
Theodoros Leontiou ◽  
Vasilis Petrou ◽  
Arun Kumar Singh ◽  
Marios Charalambides ◽  
...  
Keyword(s):  
Satellite System ◽  
Global Scale ◽  
Electron Density Profile ◽  
Radiowave Propagation ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Positioning Errors ◽  
Ionospheric Models

The objective of this article is to present a concept for single-frequency Global Navigation Satellite System (GNSS) positioning local ionospheric mitigation over a certain area. This concept is based on input parameters driving the NeQuick-G algorithm (the ionospheric single-frequency GNSS correction algorithm adopted by Galileo GNSS system), estimated on a local as opposed to a global scale, from ionospheric characteristics measured by a digital ionosonde and a collocated dual-frequency Total Electron Content (TEC) monitor. This approach facilitates the local adjustment of Committee Consultative for Ionospheric Radiowave propagation (CCIR) files and the Az ionization level, which control the ionospheric electron density profile in NeQuick-G, therefore enabling better estimation of positioning errors under quiet geomagnetic conditions. This novel concept for local ionospheric positioning error mitigation may be adopted at any location where ionospheric characteristics foF2 and M(3000)F2 can be measured, as a means to enhance the accuracy of single-frequency positioning applications based on the NeQuick-G algorithm.

Evaluation of GPS Standard Point Positioning with Various Ionospheric Error Mitigation Techniques

2016 ◽  
Vol 10 (4) ◽  
Author(s):  
Sampad K. Panda ◽  
Shirish S. Gedam
Keyword(s):  
Higher Order ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Gps Positioning ◽  
Error Mitigation ◽  
Mitigation Techniques ◽  
Point Positioning ◽  
Mitigation Methods

AbstractThe present paper investigates accuracy of single and dual-frequency Global Positioning System (GPS) standard point positioning solutions employing different ionosphere error mitigation techniques. The total electron content (TEC) in the ionosphere is the prominent delay error source in GPS positioning, and its elimination is essential for obtaining a relatively precise positioning solution. The estimated delay error from different ionosphere models and maps, such as Klobuchar model, global ionosphere models, and vertical TEC maps are compared with the locally derived ionosphere error following the ion density and frequency dependence with delay error. Finally, the positional accuracy of the single and dual-frequency GPS point positioning solutions are probed through different ionospheric mitigation methods including exploitation of models, maps, and ionosphere-free linear combinations and removal of higher order ionospheric effects. The results suggest the superiority of global ionosphere maps for single-frequency solution, whereas for the dual-frequency measurement the ionosphere-free linear combination with prior removal of higher-order ionosphere effects from global ionosphere maps and geomagnetic reference fields resulted in improved positioning quality among the chosen mitigation techniques. Conspicuously, the susceptibility of height component to different ionospheric mitigation methods are demonstrated in this study which may assist the users in selecting appropriate technique for precise GPS positioning measurements.

scholarly journals Estimating the absolute total electron content based on single-frequency satellite radio navigation GPS/GLONASS data

2017 ◽  
Vol 3 (1) ◽  
pp. 97-103
Author(s):  
Юрий Ясюкевич ◽  
Yury Yasyukevich ◽  
Анна Мыльникова ◽  
Anna Mylnikova ◽  
Всеволод Иванов ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Single Frequency ◽  
Electron Content ◽  
Dual Frequency ◽  
Total Electron ◽  
Radio Navigation ◽  
The Absolute ◽  
The Difference ◽  
A New Technique ◽  
Slant Total Electron Content

We present a new technique for estimating the absolute vertical and slant total electron content (TEC). The estimation is based on single-frequency joint phase and pseudorange GPS/GLONASS measurements at single stations. Estimated single-frequency vertical TEC agrees qualitatively and quantitatively with the dual-frequency vertical TEC. For analyzed stations a typical value of the difference between the single-frequency vertical TEC and dual-frequency ones generally does not exceed ~1.5 TECU with RMS up to ~3 TECU.

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