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

作者：Moraes Alison de Oliveira^*; Rodrigues Fabiano da Silveira; Perrella Waldecir Joao; de Paula Eurico Rodrigues

来源：Surveys in Geophysics, 2012, 33(5): 1107-1131.

DOI：10.1007/s10712-011-9161-z

• Ionosphere
• GPS
• Scintillation
• Receiver performance
• Solar maximum

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 So Jos, dos Campos, Brazil (23.2A degrees S, 45.9A degrees W, -17.5A degrees dip latitude) near the Equatorial Anomaly during high solar flux conditions. The variability of the decorrelation time (tau(0)) of scintillation patterns is presented as a function of scintillation severity index (S (4)). We found that the values of tau(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 tau(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 tau(0) in the GPS carrier loop performance for S (4) a parts per thousand yen 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 tau(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.

• 出版日期2012-9