Availability Impact on GPS Aviation due to Strong Ionospheric Scintillation

Seo, Jiwon; Walter, Todd; Enge, Per

doi:10.1109/taes.2011.5937276

Cited by 74 publications

(43 citation statements)

References 20 publications

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“…One might also consider the time it takes for the receiver to reacquire signal lock as pointed out by Seo et al (2011). The work of Carrano and Groves (2010) showed an interesting analysis about the time the GPS receiver takes to reacquire the signal after losing lock due to scintillation.…”

Section: An Assessment Of the Loss-of-lock Conditionsmentioning

confidence: 99%

Analysis of the Characteristics of Low-Latitude GPS Amplitude Scintillation Measured During Solar Maximum Conditions and Implications for Receiver Performance

et al. 2011

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Ionospheric scintillations are fluctuations in the phase and/or amplitude of trans-ionospheric radio signals caused by electron density irregularities in the ionosphere. A better understanding of the scintillation pattern is important to make a better assessment of GPS receiver performance, for instance. Additionally, scintillation can be used as a tool for remote sensing of ionospheric irregularities. Therefore, the study of ionospheric scintillation has both scientific as well as technological implications. In the past few years, there has been a significant advance in the methods for analysis of scintillation and in our understanding of the impact of scintillation on GPS receiver performance. In this work, we revisit some of the existing methods of analysis of scintillation, propose an alternative approach, and apply these techniques in a comprehensive study of the characteristics of amplitude scintillation. This comprehensive study made use of 32 days of high-rate (50 Hz) measurements made by a GPS-based scintillation monitor located in São José dos Campos, Brazil (23.2°S, 45.9°W, -17.5°dip latitude) near the Equatorial Anomaly during high solar flux conditions. The variability of the decorrelation time (s 0 ) of scintillation patterns is presented as a function of scintillation severity index (S 4 ). We found that the values of s 0 tend to decrease with the increase of S 4 , confirming the results of previous studies. In addition, we found that, at least for the measurements made during this campaign, averaged values of s 0 (for fixed S 4 index values) did not vary much as a function of local time. Our results also indicate a significant impact of s 0 in the GPS carrier loop performance for S 4 C 0.7. An alternative way to compute the probability of cycle slip that takes into account the fading duration time is also presented. The results of this approach show a 38% probability of cycle slips during strong scintillation scenarios (S 4 close to 1 and s 0 near 0.2 s). Finally, we present results of an analysis of the individual amplitude fades observed in our set of measurements. This analysis suggests that users operating GPS receivers with C/N 0 thresholds around 30 dB-Hz and above can be affected significantly by low-latitude scintillation.

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Section: An Assessment Of the Loss-of-lock Conditionsmentioning

confidence: 99%

Analysis of the Characteristics of Low-Latitude GPS Amplitude Scintillation Measured During Solar Maximum Conditions and Implications for Receiver Performance

et al. 2011

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“…Simultaneous loss of two or more GPS satellites can severely degrade the accuracy of SBAS service and affect the availability due to undersampling of ionospheric pierce points. Severe scintillation over a large coverage area can potentially cause the short service outage [9]. Since SBAS comprises of ground segment (Reference stations, Master control centre and Uplink station), user segment (SBAS receivers at L1/L5), and space segment (GPS and geostationary satellites); all tied in a loop, the scintillation effect at any of the elements of these segments will manifest in the form of degraded accuracy and reduced availability of the service as shown by schematic diagram in Figure 4.…”

Section: Impact Of Scintillation On Gnssmentioning

confidence: 99%

Improvement of Position Accuracy with GAGAN and the Impact of Scintillation on GNSS

Sunda¹,

Vyas²,

Satish³

et al. 2013

POS

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GAGAN is an Indian implementation of Satellite Based Augmentation System (SBAS), developed jointly by Airports Authority of India (AAI) and Indian Space Research Organisation (ISRO). It is in final operational phase with all the required ground and space segments ready. With the availability of GAGAN signal-in-space (SIS), the improvement in position solution is investigated using the two collocated dual frequency GPS receivers. One of the receivers was configured as SBAS receiver and the other was kept as GPS stand-alone receiver. It is found that accuracy in position improved significantly in SBAS receiver due to GAGAN correction. The impact of scintillation on GNSS was also investigated in terms of position degradation and loss of lock of the satellite signals. The manyfold effects of scintillation on GPS and SBAS are discussed in detail. The results indicate ~15% reduction in number of measurements due to loss of lock during severe scintillation.

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“…Although much research on the occurrences of equatorial ionospheric plasma irregularities in affecting SBAS performances has been done extensively in the American and Asian sectors, including the Indian subcontinent (2000;Rama Rao et al, 2006;Walter et al, 2007;Pandya et al 2007;Sparks et al, 2011;Seo et al, 2011;Sunda et al, 2013), a welldefined study on the occurrences of plasma irregularities and its effect on SBAS performance in the low-latitude African sector, where the ionosphere is more turbulent compared to the Indian subcontinent, is still lacking. The reason could be because to date there is no operational SBAS in the region and the GNSS ground observations are limited in a way.…”

Section: Introductionmentioning

confidence: 99%

Signature of ionospheric irregularities under different geophysical conditions on SBAS performance in the western African low-latitude region

et al. 2017

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Abstract. Rate of change of TEC (ROT) and its index (ROTI) are considered a good proxy to characterize the occurrence of ionospheric plasma irregularities like those observed after sunset at low latitudes. SBASs (satellite-based augmentation systems) are civil aviation systems that provide wide-area or regional improvement to single-frequency satellite navigation using GNSS (Global Navigation Satellite System) constellations. Plasma irregularities in the path of the GNSS signal after sunset cause severe phase fluctuations and loss of locks of the signals in GNSS receiver at low-latitude regions. ROTI is used in this paper to characterize plasma density ionospheric irregularities in central-western Africa under nominal and disturbed conditions and identified some days of irregularity inhibition. A specific low-latitude algorithm is used to emulate potential possible SBAS message using real GNSS data in the western African low-latitude region. The performance of a possible SBAS operation in the region under different ionospheric conditions is analysed. These conditions include effects of geomagnetic disturbed periods when SBAS performance appears to be enhanced due to ionospheric irregularity inhibition. The results of this paper could contribute to a feasibility assessment of a European Geostationary Navigation Overlay System-based SBAS in the sub-Saharan African region.

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Availability Impact on GPS Aviation due to Strong Ionospheric Scintillation

Cited by 74 publications

References 20 publications

Analysis of the Characteristics of Low-Latitude GPS Amplitude Scintillation Measured During Solar Maximum Conditions and Implications for Receiver Performance

Analysis of the Characteristics of Low-Latitude GPS Amplitude Scintillation Measured During Solar Maximum Conditions and Implications for Receiver Performance

Improvement of Position Accuracy with GAGAN and the Impact of Scintillation on GNSS

Signature of ionospheric irregularities under different geophysical conditions on SBAS performance in the western African low-latitude region

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