Testing the conformity of GPS and IRNSS in terms of ionospheric delay and position errors
01 Feb 2018-
TL;DR: The present study is focused on the variations of the IRNSS signals at different frequencies as well as with GPS, based on the parameters of ionospheric delay and receiver position.
Abstract: With the establishment of Indian Regional Navigation Satellite System (IRNSS), India envisages to have an independent navigation system apart from GNSS. This system also brings great opportunity to the space science community to compare and study its performance with existing satellite-based navigation systems. The present study is focused on the variations of the IRNSS signals at different frequencies as well as with GPS, based on the parameters of ionospheric delay and receiver position.
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01 Feb 2020
TL;DR: Automobile was fitted with embedded chip consisting of satellite navigation receivers and cellular sender and digital signature was used to avoid any tempering both on the sender side and on network.
Abstract: Multiple GNSS were used to detect wrong lane driving. Accuracy was enhanced by combining with regional satellite navigation systems. Observations were combined with cellular based navigation to further enhance accuracy. Number plate, engine number, chasis number, social security number, license number and bank account number were linked in a database maintained by government. If any instance of wrong lane driving was detected then fine would be automatically deducted from driver’s bank account and added to the bank account of police. Assisted GPS was used for enhanced speed. Digital signature was used to avoid any tempering both on the sender side and on network. Entire design was implemented on tamper proof hardware. Automobile was fitted with embedded chip consisting of satellite navigation receivers and cellular sender. Using more than one system in parallel also increased the fault tolerance of the device. The device could work on any kind of terrain and altitude. More the number of satellites in sky, more is the accuracy. The system was fully automated and secure.
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Cites methods from "Testing the conformity of GPS and I..."
...Elevation, azimuth, and ionospheric delay (Ionodelay) have been recorded as a function of UT in dual‐frequency mode (L5 + S) of IRNSS with 1 s sampling interval during 22 April 2019 to 7 June 2019....
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...IRNSS‐TEC has been analyzed from the dual‐frequency Ionodelay (Biswas et al., 2018) data by applying the equation TEC ¼ c × Ionodelay × S2 − L52 =40:3 × 1016 TECU: In the abovementioned equation, S and L5 stands for the S and L5 operating frequencies of IRNSS, and c is the speed of light....
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...IRNSS‐TEC has been analyzed from the dual‐frequency Ionodelay (Biswas et al., 2018) data by applying the equation...
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References
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TL;DR: In this article, the authors used the Global Ultraviolet Imager (GUVI) data collected during evening at solar maximum to study the morphology of these so-called collapses, since the EIA collapse is shown to be linked to the suppression of equatorial plasma bubbles and scintillations.
Abstract: [1] The day-to-day variability in ionospheric irregularity generation giving rise to equatorial scintillation has remained an unresolved issue over many decades. We take a fresh look at the problem utilizing the global imagery provided by the Global Ultraviolet Imager (GUVI) instrument on NASA's Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics satellite. GUVI has been acquiring images of 135.6-nm emission in the Earth's ionosphere-thermosphere system since 2001. These GUVI disk images at dusk have been used to identify cases where the equatorial ionization anomaly (EIA) crests lie near the magnetic equator over a relatively narrow longitude range, so that the anomaly looks collapsed. A 16-month period of GUVI data collected during evening at solar maximum is used to study the morphology of these so-called collapses, since the EIA collapse is shown to be linked to the suppression of equatorial plasma bubbles and scintillations. In particular, we look at the June solstice, during which the Atlantic and Pacific show very different climatology and EIA collapses are most frequent in the GUVI data. On the other hand, EIA collapses are a relatively rare occurrence during the equinox period when scintillations are most prevalent globally. We obtained a few dramatic examples of day-to-day variability in EIA behavior and scintillations over India. The Sami3 is Also a Model of the Ionosphere (SAMI3) model was used to investigate the conditions during the evening collapse of the anomaly in the Indian longitude sector, where measurements of total electron content (TEC) and scintillations and estimates of the daytime vertical drifts and those at dusk were available. Results from SAMI3 show that the observed collapse of the anomaly at dusk can be simulated by a reversal of the upward vertical drift in midafternoon in agreement with the drift estimates from magnetometer observations. Such reversed vertical drifts at this time of the day are generally seen during counterelectrojet events. Introduction of neutral winds into SAMI3 better approximates the dusk behavior of TEC at low-latitude stations in India. This study reveals that the longitudinally confined EIA collapse may explain some of the differences in day-to-day variability of scintillations at different locations around the globe.
58 citations
TL;DR: In this article, the authors highlight the necessity for a differential grid size around the northern crest of the EIA using data recorded from stations under the Indian SBAS GAGAN during the moderate sunspot number year 2004.
19 citations
"Testing the conformity of GPS and I..." refers methods in this paper
...The ionospheric delay has been converted from slant to vertical value using the slanting factor [5][6]....
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TL;DR: In this paper, the poleward gradient of the EIA introduces more intense propagation effects on transionospheric satellite links in comparison to the equatorward gradient, and a threshold value of poleward TEC gradient is calculated above which there is a probability of scintillation at Calcutta with S4 ≥ 0.4.
Abstract: . The poleward gradient of the equatorial ionization anomaly (EIA) introduces more intense propagation effects on transionospheric satellite links in comparison to the equatorward gradient. Characterization of the poleward gradient was performed during March–April, August–October 2011 and March–April 2012 using GPS total electron content (TEC) recorded from a chain of stations located more or less along the same meridian (88.5° E) at Calcutta, Baharampore, Farakka and Siliguri. The poleward gradients calculated on magnetically quiet days at elevation in excess of 50° at 14:00, 15:00 and 16:00 LT were found to have a strong correlation with GPS S4 observed from Calcutta during post-sunset-to-midnight hours. A threshold value of poleward TEC gradient is calculated above which there is a probability of scintillation at Calcutta with S4 ≥ 0.4.
17 citations
"Testing the conformity of GPS and I..." refers methods in this paper
...The ionospheric delay has been converted from slant to vertical value using the slanting factor [5][6]....
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