Case study: NavIC Performance Observation on Low Latitude Region

2021 ◽  
Author(s):  
Darshna D. Jagiwala ◽  
Shweta N. Shah ◽  
Mehul V. Desai
Keyword(s):  
Low Latitude ◽  
Latitude Region

scholarly journals Statistical correlation of spectral broadening in VLF transmitter signal and low-frequency ionospheric turbulence from observation on DEMETER satellite

2008 ◽  
Vol 8 (5) ◽  
pp. 1105-1111 ◽  
Author(s):  
A. Rozhnoi ◽  
M. Solovieva ◽  
O. Molchanov ◽  
O. Akentieva ◽  
J. J. Berthelier ◽  
...  
Keyword(s):  
Middle Latitude ◽  
Statistical Correlation ◽  
Occurrence Rate ◽  
Signal Spectrum ◽  
Ionospheric Turbulence ◽  
Low Latitude ◽  
Demeter Satellite ◽  
Ion Cyclotron ◽  
Latitude Region

Abstract. In our earlier papers we have found the effect of VLF transmitter signal depression over epicenters of the large earthquakes from observation on the French DEMETER satellite that can be considered as new method of global diagnostics of seismic influence on the ionosphere. At present paper we investigate a possibility VLF signal-ionospheric turbulence interaction using additional characteristic of VLF signal-spectrum broadening. This characteristic is important for estimation of the interaction type: linear or nonlinear scattering. Our main results are the following: – There are two zones of increased spectrum broadening, which are centered near magnetic latitudes Φ=±10° and Φ=±40°. Basing on the previous case study research and ground ionosonde registrations, probably it is evidence of nonlinear (active) scattering of VLF signal on the ionospheric turbulence. However occurrence rate of spectrum broadening in the middle-latitude area is higher than in the near-equatorial zone (~15–20% in comparison with ~100% in former area) that is probably coincides with the rate of ionospheric turbulence. – From two years statistics of observation in the selected 3 low-latitude regions and 1 middle-latitude region inside reception area of VLF signal from NWC transmitter we find a correlation of spectrum broadening neither with ion-cyclotron noise (f=150–500 Hz), which possibly means poor representation of the turbulence by the noise due to its mixture with natural ELF emission (which correlates with whistler), nor with magnetic storm activity. – We find rather evident correlation of ion-cyclotron frequency noise, VLF signal depression and weak correlation of spectrum broadening with seismicity in the middle-latitude region over Japan. But in the low-latitude regions we do not find such a correlation. Statistical decrease of VLF signal supports our previous case study results. However rather weak spectrum broadening-seismicity statistical correlation means probably that passive scattering prevails upon nonlinear (active) one.

scholarly journals Ionospheric Effects on GPS Signal in Low-Latitude Region: A Case Study Review of South East Asia and Africa

2015 ◽  
Vol 34 (3) ◽  
pp. 523 ◽  
Author(s):  
I Abba ◽  
WAWZ Abidin ◽  
T Masri ◽  
KH Ping ◽  
MS Muhammad ◽  
...  
Keyword(s):  
East Asia ◽  
South East Asia ◽  
Low Latitude ◽  
Ionospheric Effects ◽  
Latitude Region ◽  
Study Review

scholarly journals Performance of Network-Based RTK GPS in Low-Latitude Region: A Case Study in Thailand

2012 ◽  
Vol 16 (5) ◽  
pp. 95-104 ◽  
Author(s):  
Teeratat Charoenkalunyuta ◽  
Chalermchon Satirapod ◽  
Hung-Kyu Lee ◽  
Yoon-Soo Choi
Keyword(s):  
Low Latitude ◽  
Latitude Region ◽  
Rtk Gps

scholarly journals Climatology of intermediate descending layers (or 150 km echoes) over the equatorial and low-latitude regions of Brazil during the deep solar minimum of 2009

2019 ◽  
Vol 37 (6) ◽  
pp. 1005-1024 ◽  
Author(s):  
Ângela Machado dos Santos ◽  
Inez Staciarini Batista ◽  
Mangalathayil Ali Abdu ◽  
José Humberto Andrade Sobral ◽  
Jonas Rodrigues de Souza ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Solar Minimum ◽  
Interesting Case ◽  
Time Interval ◽  
Low Latitude ◽  
Prompt Penetration Electric Field ◽  
Latitude Region ◽  
First Time

Abstract. In this work, we have performed a study for the first time on the climatology of the intermediate descending layers (ILs) over Brazilian equatorial and low-latitude regions during the extreme solar minimum period of 2009. The result of this study shows that the occurrence frequency of the ILs is very high, being > 60 % over São Luís (2∘ S, 44∘ W; inclination: −3.8∘) and > 90 % in Cachoeira Paulista (22.42∘ S, 45∘ W; inclination: −33.5∘). In most cases the ILs occur during the day at altitudes varying from 130 to 180 km and they may descend to lower altitudes (∼100 km) in a time interval of a few minutes to hours. The main driving force for the ILs at the low-latitude region, may be considered to be the diurnal tide (24 h) followed in smaller dominance by the semidiurnal (12 h), terdiurnal (8 h) and quarter-diurnal (6 h) components. In the magnetic equatorial sector, similar behavior was seen, with the exception of the semidiurnal tide, which in general does not appear to have influenced the IL's dynamics (except in summer). Additionally, the IL mean descent velocity over São Luís and Cachoeira Paulista shows a day-to-day variability that may be associated with a wave-like perturbation with a periodicity of some days. Some peculiarities in the IL dynamics were noted, such as the presence of the ILs during the night hours. Ascending and descending ILs appeared to have been formed from some connection with the ionospheric F layer. Quite often, these characteristics are observed in the presence of strong signatures of the gravity wave propagation as suggested by the F layer traces in the ionogram. The descending intermediate layer over Brazil appears to have been formed through a process of F1 layer base detachment. An interesting case study showed that an ascending ILs, initially detected at ∼130 km, reached the base of the F2 layer, due probably to the gravity wave propagation and/or the effect of a prompt penetration electric field.

scholarly journals Case study on total electron content enhancements at low latitudes during low geomagnetic activities before the storms

2008 ◽  
Vol 26 (4) ◽  
pp. 893-903 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
Total Electron Content ◽  
Geomagnetic Activity ◽  
Electron Content ◽  
Low Latitude ◽  
Total Electron ◽  
Defense Meteorological Satellite Program ◽  
Low Latitudes ◽  
Global Ionospheric Maps ◽  
Geomagnetic Activities

Abstract. Sometimes the ionospheric total electron content (TEC) is significantly enhanced during low geomagnetic activities before storms. In this article, we investigate the characteristics of those interesting TEC enhancements using regional and global TEC data. We analyzed the low-latitude TEC enhancement events that occurred around longitude 120° E on 10 February 2004, 21 January 2004, and 4 March 2001, respectively. The TEC data are derived from regional Global Positioning System (GPS) observations in the Asia/Australia sector as well as global ionospheric maps (GIMs) produced by Jet Propulsion Laboratory (JPL). Strong enhancements under low geomagnetic activity before the storms are simultaneously presented at low latitudes in the Asia/Australia sector in regional TEC and JPL GIMs. These TEC enhancements are shown to be regional events with longitudinal and latitudinal extent. The regions of TEC enhancements during these events are confined at narrow longitude ranges around longitude 120° E. The latitudinal belts of maxima of enhancements locate around the northern and southern equatorial ionization anomaly (EIA) crests, which are consistent with those low-latitude events presented by Liu et al. (2008). During the 4 March 2001 event, the total plasma density Ni observed by the Defense Meteorological Satellite Program (DMSP) spacecraft F13 at 840 km altitude are of considerably higher values on 4 March than on the previous day in the TEC enhanced regions. Some TEC enhancement events are possibly due to contributions from auroral/magnetospheric origins; while there are also quasi-periodic enhancement events not related to geomagnetic activity and associated probably with planetary wave type oscillations (e.g. the 6 January 1998 event). Further investigation is warrented to identify/separate contributions from possible sources.

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.

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