Ionospheric Total Electron Content Variations Research Articles

A Two-Step Regional Ionospheric Modeling Approach for PPP-RTK.

In the precise point positioning/real-time kinematic (PPP-RTK) technique, high-precision ionospheric delay correction information is an important prerequisite for rapid PPP convergence. The commonly used ionospheric modeling approaches in the PPP-RTKs only take the trend term of the ionospheric total electron content (TEC) variations into account. As a result, the residual ionospheric delay still affects the positioning solutions. In this study, we propose a two-step regional ionospheric modeling approach that involves combining a polynomial fitting model (PFM) and a Kriging interpolation (KI) model. In the first step, a polynomial fitting method is used to model the trend term of the ionospheric TEC variations. In the second step, a KI method is used to compensate for the residual term of the ionospheric TEC variations. Datasets collected from continuously operating reference stations (CORSs) in Hunan Province, China, are used to validate the PFM/KI method by comparing with a single PFM method and a combined PFM and inverse distance weighting interpolation (IDWI) method. The experimental results show that the two-step PFM/KI modeled ionospheric delay achieves an average root mean square (RMS) error of 1.8 cm, which is improved by about 48% and 23% when compared with the PFM and PFM/IDWI methods, respectively. Regarding the positioning performance, the PPP-RTK with the PFM/KI method takes an average of 1.8 min or 4.0 min to converge to a positioning accuracy of 1.3 cm or 2.5 cm in the horizontal and vertical directions, respectively. The convergence times are decreased by about 18% and 14% in the horizontal direction and 9% and 5% in the vertical direction over the PFM and the PFM/IDWI methods, respectively.

О возможности детектирования ионосферных возмущений, вызванных мощными подземными взрывами, методами GNSS-радиопросвечивания

Using dense networks of GNSS receivers, an analysis of the ionospheric responses to two underground explosions with a magnitude less than the existing threshold for detecting the ionospheric response to earthquakes was carried out. It is shown that when regestering these responses, it is necessary to take into account the possible anisotropy of the propagation of atmospheric disturbances at ionospheric altitudes due to both large-scale wind structures and the inclination of the geomagnetic field. Taking these factors into account makes it possible to reduce the magnitude threshold (compared to that established for earthquakes) of impulse lithospheric sources (explosions, volcanic explosions), the response to which can still be detected in the ionospheric total electron content variations.

Influence of solar radiation on ionosphere over India

The ionosphere is a region of the upper atmosphere where free electrons and ions are created by solar radiation. An effort is made to study the solar radiation influence on the earth's ionosphere's total electron content (TEC) across the low latitude Indian subcontinent from January to October 2022. TEC readings were obtained using GNSS receivers over Bengaluru (13.021 °N, 77.570 °E) and Hyderabad (17.417 °N, 78.551 °E). Ionospheric TEC variations are studied by measuring the degree to which satellite-sent GPS signals are disrupted. The results were compared with geomagnetic measurements such as disturbed storm time (Dst) index and planetary K-index (Kp) and analyzed with TEC anomalies during geomagnetic storms, and the results may be used to estimate the magnetic field of the Earth. The study revealed that ionospheric storms had an advantageous impact in January, March, and April of 2022, but a negative effect in July 2022.

Ionospheric TEC variation over Svalbard archipelago, Norway and assessment of Bilinear interpolated GIM model

The Svalbard archipelago region is a group of islands in the Arctic Ocean, located between the North Pole and the northern coastal region of Norway at high latitudes. The current study focuses on the spatiotemporal distribution of total electron content (TEC) over the Svalbard archipelago region with the ground-based global positioning system (GPS) tracking stations during the years 2020–2022. The spatial ionospheric TEC characteristics from GPS observables and their correlation with the Bilinear interpolated global ionospheric map (GIM) and the latest edition of the international reference ionosphere (IRI- 2020) model are investigated. The results showed that both GPS-TEC and GIM-TEC have minimum ionospheric TEC during the winter season while they have maximum TEC occurrence in the summer and spring seasons with a higher difference of magnitude. We suspect such discrepancy could be due to expected uncertainties in the estimation of GIM-TEC interpolation over the region. The correlation coefficients between GPS-TEC versus GIM-TEC and GPS-TEC versus IRI-TEC showed that they are correlated with an almost equivalent correlation coefficient of approximately 0.76 which is reasonably acceptable but relatively lower than other middle latitude regions. This poor correlation happened because of the diurnal variation in the polar cap region during the summer season which is minimal. Finally, a Multitaper spectral analysis is employed on the frequency spectra of the time-varying periodograms of the four oscillation components. The outcome of the spectral analysis confirms that the first principal component (PC) of GPS-TEC is well correlated with the respective PC of GIM and IRI models. Although the higher order PCs of GIM models remain well-correlated with GPS-TEC, the subdued correlation between IRI model outputs and GPS-TEC suggests further improvements in the IRI model representation with respect to the high latitude characteristics.

Ionospheric TEC Variation and Gravity Waves Signatures During the Solar Eclipse on 21 June 2020 Over Southern China

AbstractThe total electron content (TEC) derived from ground‐based BeiDou geostationary orbit (GEO) satellite receivers lying on both sides of the eclipse path is used to study the ionospheric variations in southern China, particularly targeting eclipse‐induced gravity waves in the ionosphere during the annular solar eclipse on 21 June 2020. Eclipse‐induced gravity waves (GWs) signatures with periods of about 70 min, from wavelet analysis, were identified on both sides of TEC observations, which are most likely to be induced in the thermosphere. However, there were significant differences in the intensity of the gravity waves on both sides of the eclipse path, gravity waves are stronger on the northern side of the eclipse path than on the southern side. Moreover, a postponement of TEC depletion shows on the northern side of the eclipse path which is caused by the convergence effect of the wind field. And at the same obstruction rate, GWs possibly can slightly adjust the postponement of TEC depletion on a small scale.

Longitudinal Variations in Equatorial Ionospheric TEC from GPS, Global Ionosphere Map and International Reference Ionosphere-2016 during the Descending and Minimum Phases of Solar Cycle 24

Research on longitudinal discrepancies in local ionospheric variability, especially in equatorial and low-latitude regions, is a focal point of interest for the space weather modeling community. The ionosphere over these regions is influenced by complex electrodynamics, wind, and temperature dynamics that can seriously impact dynamic technological systems such as satellite tracking and positioning, satellite radio communication, and navigation control systems. Here, we researched the longitudinal variability in the ionospheric total electron content (TEC) by analyzing observed global positioning system (GPS)-derived TEC values along with those extracted from the most reliable global ionospheric maps (GIMs) and the International Reference Ionosphere (IRI-2016) model at selected stations in the vicinity of the magnetic equator along the American, African, and Asian longitude sectors. The period of study covered the descending (2016–2017) and deep solar minimum (2018–2019) years in the 24th solar cycle. Apart from the decreasing trend of the TEC from the descending to deep solar minimum period irrespective of season and longitude sector, the results showed a relatively higher magnitude of TEC in the African longitude than the other two longitude sectors. Despite evident overestimation and underestimations of TEC in both models, GIM predictions generally looked better in terms of observed variation patterns, especially in the African longitude. The study also highlights the seasonal and semiannual effects of longitudinal variations in TEC, manifesting in local time offsets and some peculiar anomalies, which seemed to be different from previously reported results, especially during the solar minimum years at the three longitude sectors. The insignificant effects of longitudinal variations on the equinoctial asymmetry are attributed to the diverse electron density distribution and ionospheric morphology at the three longitude sectors that will prompt further investigations in the future. The outcomes from this study may augment the past efforts of scientists to understand the seasonal effects of the longitudinal variations in TEC, thereby complementing the improvements of ionospheric representations in global ionosphere models and maps.

Variations of ionospheric TEC due to coronal mass ejections and geomagnetic storm over New Zealand

The variations of ionospheric Total electron content (TEC) due to coronal mass ejections (CMEs) and geomagnetic storms over New Zealand were studied. TEC data were collected from dual-frequency GPS sites operated by the University NAVSTAR Consortium in New Zealand, at Ous2 (−45.86°N, 170.51°E), Dund (−45.89°N, 170.59°E), Mtjo (−43.99°N, 170.46°E), and Quar (−43.53°N, 169.81°E) stations. The findings of this study show that the variability of ionospheric TEC was more noticeable during the main phase of the storm on September 08, 2017 than the initial phase on September 07, 2017, recovery phase on September 09, 2017, and during the CME day on September 06, 2017. Also, the enhancements of change in TEC (ΔTEC) were pronounced more over the Mtjo station during the CME day and over the Quar station during the geomagnetic storm day than over other stations. On September 06, 2017, two X-class solar flares, specifically X2.2 and X9.3, were observed with quiet geomagnetic storm conditions throughout the CME day, resulting in an increase in TEC. On September 07, 2017, the M7.3, X1.3, and on September 08, 2017, the X8.1 solar flare classes with disturbed geomagnetic conditions led to a significant enhancement of TEC over the stations at 02:00 UT (13:00 LT). Finally, during the main phase of the storm, the solar wind electric field (IEF Ey) and prompt penetration electric field (PPEF) showed good correlations in which the fluctuation of PPEF, an increase in Ey, Dst minimum, and horizontal Earth’s magnetic field are well associated with strong changes in TEC.

GPS observations of ionospheric TEC variations over Nepal during 22 July 2009 solar eclipse

As the study of ionospheric behavior during various solar activities is an important task, various studies of ionospheric changes during eclipse events have been widely performed in the different regions of the globe. This paper investigates the ionospheric responses to the solar eclipse on 22 July 2009 over Nepal using the total electron content (TEC) measured by dual-frequency Global Positioning System (GPS) receivers. The time-averaged Vertical TEC (vTEC) of ten GPS stations from Nepal is analyzed and it is found that the value of ionospheric TEC decreases due to the reduction of ionizing radiation. In addition, the deviation in the TEC value on eclipse day from the mean vTEC value of the top five quietest days is found to lie in the range ~1–5 TECu at those regions which were associated with the partial eclipse shadow. On the other hand, the region with the total eclipse (BRN2 and RMTE) faced ~6–7 TECu on average reduction in the TEC value. Considering that the eclipse of 22 July 2009 occurred just at sunrise in the Nepalese zone, a maximum reduction of about 5 TECu is very significant. Higher deviation in TEC is therefore linked with the path of totality and the obscuration rate. This study reveals that the ionospheric TEC over Nepal was altered by wave-like energy and momentum transport, as well as obscuration of the solar disc due to the partial and total solar eclipse. Furthermore, the cross-correlation results presented similar type signatures of the eclipse-induced ionospheric modification over Nepal. This research work serves a crucial future reference for the comparative study of change of ionospheric TEC variability over the Nepal region during Eclipse events

A comparative study of ionospheric TEC diurnal variations at two stations near cusp latitudes in the Southern Hemisphere

Based on ionospheric total electron content (TEC) data for Zhongshan station (ZHS) and Scott Base station (SBA) in Antarctica, acquired during 2010–2020, high-latitude ionospheric TEC diurnal variations of two near cusp latitude stations were studied. The magnetic latitude and longitude differences between the two stations were approximately 5° and 135°, respectively. It was found that during the 11-year solar activity cycle, the maximum diurnal variation of the ionospheric TEC at ZHS occurred mainly between local noon and magnetic noon. Statistically, the TEC peaks occurred closer to local (magnetic) noon under low (high) solar activity conditions. The maximum diurnal variation of ionospheric TEC at SBA occurred mainly around local noon under low solar activity conditions but before magnetic midnight under high solar activity conditions. The effects of solar radiation, particle precipitation, and polar ionospheric convection pattern on the diurnal variation of TEC were investigated. At both stations, photoionization caused by solar radiation was the main reason for the maximum diurnal variation of ionospheric TEC around local noon. During high solar activity with high concentration plasma in the dayside polar ionosphere, the convection pattern was the dominant influence on the maximum diurnal variation of TEC before magnetic midnight (noon) at SBA (ZHS).

A Study of Possible Correlations between Seismo-Ionospheric Anomalies of GNSS Total Electron Content and Earthquake Energy

In this study, we conduct a correlation analysis between the daily occurrence times of the increase and decrease anomalies in the global total electron content (TEC) in the ionosphere, and the daily earthquake energy release within 110–130°E longitude over the following three latitude regions: A: 13°S–0.5°S (22.3°S–10°S geomagnetic), B: 0.5°S–19.5°N (10°S–10°N geomagnetic), and C: 19.5°N–32.1°N (10°N–22.5°N geomagnetic). The TEC data from global ionosphere maps (GIMs) during earthquake events of M ≥ 2.5 that occurred in 2015–2018 are used in this study. The time series of daily seismic wave energy releases within the three regions and the daily occurrence times of the TEC anomalies in each GIM grid are computed. By time-shifting the time series, the correlations are calculated and compared globally, and the temporal characteristics are also examined. The disturbance storm time (Dst) index, planetary geomagnetic index Kp, and daily observed 10.7 cm solar flux (F10.7) are used to remove data associated with space weather variations. Although the seismo-ionospheric precursor is not confirmed by the statistical investigations, the greater occurrence times of TEC decrease anomalies are observed in the southeast in Region A, and the conjugate point 13 days prior to a M6.9 earthquake in Region A, which occurred on 5 August 2018, in accordance with the statistical results. Therefore, it is required to apply more parameters to understand the causes of the ionospheric TEC variations and investigate whether ionospheric variations are caused by earthquakes.

Rare observations of sprites and gravity waves supporting D, E, F-regions ionospheric coupling

We report rare simultaneous observations of columniform sprites and associated gravity waves (GWs) using the Transient Luminous Events (TLEs) camera and All-sky imager at Prayagraj (25.5° N, 81.9° E, geomag. lat. ~ 16.5° N), India. On 30 May 2014, a Mesoscale Convective System generated a group of sprites over the north horizon that reached the upper mesosphere. Just before this event, GWs (period ~ 14 min) were seen in OH broadband airglow (emission peak ~ 87 km) imaging that propagated in the direction of the sprite occurrence and dissipated in the background atmosphere thereby generating turbulence. About 9–14 min after the sprite event, another set of GWs (period ~ 11 min) was observed in OH imaging that arrived from the direction of the TLEs. At this site, we also record Very Low Frequency navigational transmitter signal JJI (22.2 kHz) from Japan. The amplitude of the JJI signal showed the presence of GWs with ~ 12.2 min periodicities and ~ 18 min period. The GWs of similar features were observed in the ionospheric Total Electron Content variations recorded at a nearby GPS site. The results presented here are important to understand the physical coupling of the troposphere with the lower and upper ionosphere through GWs.

Statistical Behavior of Large‐Scale Ionospheric Disturbances From High Latitudes to Mid‐Latitudes During Geomagnetic Storms Using 20‐yr GNSS‐TEC Data: Dependence on Season and Storm Intensity

AbstractTo establish the statistical behavior of ionospheric TEC variations from high latitudes to mid‐latitudes during the main and recovery phases of geomagnetic storms, we conducted a superposed epoch analysis of interplanetary magnetic field, solar wind, geomagnetic indices (AE and SYM‐H), and global navigation satellite system (GNSS)‐total electron content (TEC) data for 20 yr (2000–2019). In this study, we identify 663 geomagnetic storm events with the minimum SYM‐H value of less than −40 nT and investigate the characteristics of the TEC variations for the weak (−60 ≤ SYM‐Hmin < −40 nT), moderate (−100 ≤ SYM‐Hmin < −60 nT), and strong (−150 ≤ SYM‐Hmin < −100 nT) geomagnetic storms. The main results obtained from the present study are as follows: (a) The TEC enhancements related to the tongue of ionization (TOI), auroral oval, and storm‐enhanced density (SED) plume are more dominant in winter than in summer during the main phase of geomagnetic storms. (b) The structure of the mid‐latitude trough in the nighttime sector becomes unclear in winter. (c) The TEC depletion at auroral and mid‐latitudes (40°–70° GMLAT: geomagnetic latitude) starts to appear in the morning sector (8–10 hr GMLT: geomagnetic local time) during the main phase of geomagnetic storms and the decreased region extends in the lower latitude and GMLT directions with time. The negative storm activity tends to be enhanced significantly as the storm intensity becomes larger. The activity of the TEC depletion is dominant in summer than in winter, which is agreement with the classical ionospheric storm scenario.

Ionospheric TEC variation based on GNSS data over the Arabian Peninsula and validation with the cubic spline interpolated GIM model

The study examined the ionospheric total electron content (TEC) variation based on global navigation satellites system (GNSS) stations located inside the Arabian Peninsula. An interpolation technique known as cubic spline is used and numerical investigation of TEC variation has been carried out from 2015 to 2017. First, global ionospheric map (GIM) data is interpolated with the help of the cubic spline interpolation method and then compared with observed GNSS TEC values. Correlation coefficients between observed and interpolated GIM TEC are very high (about 0.95), indicating a strong relationship. Normal correlation coefficients were not enough to establish their relationship; hence, the wavelet plot of the first four principal components of each series is plotted and again their correlation coefficients are studied. Although their correlation is good enough, the wavelet analysis points out the variability of each series, that they are not quite same. The low and high peaks of each series are different; which means, the lowest and highest peaks of both series do not occur at the same time. This can happen because there are few international GNSS service stations available over the Arabian Peninsula that becomes a cause of error in the interpolation of GIM data. This type of study indicates only simple comparisons such as correlation coefficient and a standard deviation is not enough for comparative analysis; we need to study it in depth by using suitable statistical tools.

Local and conjugate ionospheric total electron content variation during the 21 June 2020 solar eclipse

• Ionospheric TEC showed an asymmetric latitudinal depletion around totality path. • Ionospheric disturbances in both local and conjugate eclipse regions were analyzed. • Eclipse-induced ionospheric bow wave structures and TIDs were identified. This paper studies the ionospheric response to a low-latitude annular solar eclipse event on 21 June 2020 at both eclipse and conjugate regions using a dense network of Global Navigation Satellite Systems receivers, Defense Meteorological Satellite Program and Swarm satellites data, as well as ionosonde measurements over the Asian-Oceania sector. The large scale ionospheric variation and small scale wave-like perturbations during the eclipse were analyzed by using high-resolution Total Electron Content (TEC) maps and in-situ electron density/temperature data. The main results are as follows: (1) A local TEC reduction of 4–7 TEC Unit ( ∼ 30–50%) was identified along the totality path, with larger depletion in the southern edge of totality path than the northern edge. (2) The equatorial ionization anomaly in the Asian sector exhibited a complicated variation pattern with a slightly different longitudinal/local time and altitudinal response, which showed considerable TEC/ Ne depletion in the East Asian sector and at ∼ 850 km close to local afternoon during the eclipse, but a slight TEC/ Ne enhancement around the Indian sector and at ∼ 500 km in the post-eclipse periods. (3) Large ionospheric perturbations were identified that traveled at approximately the same velocity as the supersonic moon shadow, and the ionospheric bow wave features were also triggered by the solar eclipse. (4) The Oceania TEC in the Southern Hemisphere conjugate location experienced a coincident minor reduction and wave-like fluctuations during the eclipse, likely indicating some possible interconnections between the eclipse and the conjugate ionospheres.

Some statistics of Ionospheric total electron content variations at mid-latitude zones of Mongolia

This work is focused on the correlation of ionosphere total electron content (TEC) with solar and geomagnetic activities of the space weather at mid-latitude zone. In our analysis, we investigate the TEC time series obtained from dual-frequency GNSS (Global Navigation Satellite System) observations at three continuous GPS/GNSS stations HOVD (48.00N, 91.66E), CHOB (48.08N, 114.53E) and DALN (43.56N, 104.42) for 2013. The statistical analyses are performed on 15 minute averaged yearly TEC values, which reveal the semi-annual anomaly and high correlation with the activities of the Sun and the rotation of the Earth. Phase overlapping seasonal variations of TEC and Sunspot, and Solar flux (10.7) indices, and Earth rotations (LOD) and Atmospheric angular moment (AAM) are observed in our data analyses. Sudden ionospheric storm changes in TEC with geomagnetic storm induced by the extreme solar flare and 2013 events were investigated. The result shows that GPS derived TEC behaves as an indicator of these events showing sudden increase in TEC during the event.

Global Positioning System Observations of Ionospheric Total Electron Content Variations During the 15th January 2010 and 21st June 2020 Solar Eclipse

AbstractThe dual‐frequency global positioning system (GPS) data acquired from the UNAVCO over different places of Nepal were processed to examine the eclipse‐triggered consequences on total electron content (TEC) in response to the annular solar eclipse of 15th January 2010 and 21st June 2020. These occasions were exceptional since they occurred during solar minimum, additionally as in a magnetically quiet period. The eclipse phase coincided with the peak ionization‐time at the equatorial and low latitude regions. The solar eclipse of 21st June 2020 was an annular solar eclipse with a magnitude of 0.994. Nepal has witnessed a partial eclipse, starting at ∼10:53 NST (05:08 UT), reached the maximum at ∼12:40 NST (6:55 UT), and ended at ∼14:24 NST (8:39 UT) with the total duration of 3 h and 31 min. The annular solar eclipse of 15th January 2010 had the magnitude of 0.919 and Nepal has witnessed a partial eclipse starting at ∼12:24 NST (6:39 UT), reached the maximum at ∼14:10 NST (8:25 UT), and ended at ∼15:40 NST (9:55 UT). The eclipse effect occurs as a trough‐like depression in the curve of TEC at all the GPS stations indicates the effect of sudden attenuation of solar extreme ultra‐violet irradiation on decayed electron content in the ionosphere over the region. Moreover, the extent of the exhaustion in ionospheric TEC was studied by comparing the eclipse day TEC with mean diurnal ionospheric TEC of five quietest days of the month to investigate the eclipse effect on the electron density of the ionosphere over the stations. The study additionally reveals that the measure of the decrease in vertical value of total electron content is proportional to the obscuration of the lunar disc, that is closely associated with the electron production via the photoionization process. Observing the values of TEC during the eclipse day and comparing it with other quiet days, our study showed an apparent variation during the time of the eclipse, which agrees with previous studies on ionospheric responses to the eclipse as well as theoretical assumptions.

Study of Spatial and Temporal Variations of Ionospheric Total Electron Content in Japan, during 2014-2019 and the 2016 Kumamoto Earthquake.

There are a large number of excellent research cases in Global Navigation Satellite System (GNSS) positioning and disaster prediction in Japan region, where the simulation and prediction of total electron content (TEC) is a powerful research method. In this study, we used the data of the GNSS Earth Observation Network (GEONET) established by the Geographical Survey Institute of Japan (GSI) to compare the performance of two regional ionospheric models in Japan, in which the spherical cap harmonic (SCH) model has the best performance. In this paper, we investigated the spatial and temporal variations of ionospheric TEC in Japan and their relationship with latitude, longitude, seasons, and solar activity. The results show that the TEC in Japan increases as the latitude decreases, with the highest average TEC in spring and summer and the lowest in winter, and has a strong correlation with solar activity. In addition, the observation and analysis of ionospheric disturbances over Japan before the 2016 Kumamoto earthquake and geomagnetic storms showed that GNSS observing of ionospheric TEC seems to be very effective in forecasting natural disasters and monitoring space weather.

Impact of semi-annual ionospheric total electron content variation on station displacements using single-frequency PPP

Impact of semi-annual ionospheric total electron content variation on station displacements using single-frequency PPP

Investigation of GIM-TEC disturbances before M\u2009\u2265\u20096.0 inland earthquakes during 2003\u20132017

With the rapid development of the Global Navigation Satellite System (GNSS) and its wide applications to atmospheric science research, the global ionosphere map (GIM) total electron content (TEC) data are extensively used as a potential tool to detect ionospheric disturbances related to seismic activity and they are frequently used to statistically study the relation between the ionosphere and earthquakes (EQs). Indeed, due to the distribution of ground based GPS receivers is very sparse or absent in large areas of ocean, the GIM-TEC data over oceans are results of interpolation between stations and extrapolation in both space and time, and therefore, they are not suitable for studying the marine EQs. In this paper, based on the GIM-TEC data, a statistical investigation of ionospheric TEC variations of 15 days before and after the 276 M ≥ 6.0 inland EQs is undertaken. After eliminating the interference of geomagnetic activities, the spatial and temporal distributions of the ionospheric TEC disturbances before and after the EQs are investigated and compared. There are no particularly distinct features in the time distribution of the ionospheric TEC disturbances before the inland EQs. However, there are some differences in the spatial distribution, and the biggest difference is precisely in the epicenter area. On the other hand, the occurrence rates of ionospheric TEC disturbances within 5 days before the EQs are overall higher than those after EQs, in addition both of them slightly increase with the earthquake magnitude. These results suggest that the anomalous variations of the GIM-TEC before the EQs might be related to the seismic activities.

A study of ionospheric effects on IRNSS/NavIC positioning at equatorial latitudes

The Indian Regional Navigation Satellite System (IRNSS/NavIC) is fully operational and broadcasting radio signals at L5 (1176.45 MHz) and S-band (2492.028 MHz). When these signals pass through the ionosphere, carrier phase delay, which depends on Total Electron Content (TEC), causes error in positioning. Corrections are applied in the augmented navigation system to minimize the position error due to TEC; however, 100% removal of error is practically impossible. Thus, a study has been carried out to understand the role of ionospheric determinants, such as TEC and scintillation S4, on the accuracy of augmented navigation over low latitude region using a dual-frequency NAVigation with Indian Constellation (NavIC) receiver installed at BITS-Pilani K.K. Birla Goa Campus (Geog. Lat. 15.39°N, Geog. Long. 73.87°E). Data collected using the Indian Space Research Organization (ISROs) NavIC receiver (make DataPattern) during the low solar period between March 2019 to December 2019 is utilized for this study. The important findings of the study are as follows: (a) Mean position error was in the range of 2–4 m. (b) Diurnal variation of the position error indicated a maximum at afternoon hours, coinciding with the time of maximum TEC over the EIA crest region. (c) Mean position error in afternoon hours indicated a linear relation with mean TEC, in a scatter-plot analysis. (d) Statistically, the position error during the scintillation nights was found to be similar to non-scintillation nights, indicating that the post-sunset equatorial density depletions during low solar do not significantly impact navigation accuracy. Absolute position error during the active phase of a moderate geomagnetic storm of 14 May 2019 was found to be significantly higher compared to a quiet period, which also depends on the mode of operation of the augmented navigation system. It was found that a hybrid NavIC (Dual) + GPS (SBAS) augmented navigation was more accurate than NavIC with dual- ionospheric corrections or NavIC with grid corrections, alone. Besides, the dynamic behavior of the ionosphere, i.e., diurnal, monthly, and seasonal variations of ionospheric TEC, have also been studied using the iono-delay values derived from the NavIC receiver.