On the variation of radio star and satellite scintillations with zenith angle

Briggs, B. H.; Parkin, I. A.

doi:10.1016/0021-9169(63)90150-8

Cited by 365 publications

(194 citation statements)

References 17 publications

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“…It is used to measure the ionospheric scintillations and slant total electron content (STEC). The amplitude scintillation index S4 related to density irregularities is defined as the standard deviation of signal intensity normalized to its average value (Briggs and Parkin, 1963) and is computed every 1 min based on a 50 Hz sampling rate. The GISTM computes S4T (the total scintillation index) and S4c (caused by ambient noise), so we get the S4 caused by irregularities in the form described in Van Dierendonck and …”

Section: Methodsmentioning

confidence: 99%

A comparative study of GPS ionospheric scintillations and ionogram spread F over Sanya

Zhang

Wan

et al. 2015

Ann. Geophys.

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Abstract. We analyze the data recorded during December 2011-November 2012 by a digital ionosonde and a GPS (Global Positioning System) scintillation and (total electron content) TEC receiver collocated at Sanya (109.6 • E, 18.3 • N; dip lat. 12.8 • N), a low-latitude station in the Chinese longitude sector, to carry out a comparative study of ionospheric scintillations and spread F. A good consistency between the temporal variations of GPS scintillation (represented by the S4 index) and of ionogram spread F (represented by the QF index) is found in the pre-midnight period during equinox. However in the post-midnight period during equinox and in the period from post-sunset to presunrise during June solstice, moderate spread F is seen without concurrent GPS scintillation. The possible cause responsible for the difference between post-midnight GPS scintillation and spread F during equinox could be due to the decaying of 400 m scale irregularities associated with equatorial spread F. Regarding the irregularities producing moderate QF and low S4 indices during June solstice, we suggest that the frequently observed sporadic E (Es) layer and the medium-scale traveling ionospheric disturbances (MSTIDs) over Sanya could play important roles in triggering the June solstitial spread-F events.

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Section: Methodsmentioning

confidence: 99%

A comparative study of GPS ionospheric scintillations and ionogram spread F over Sanya

Zhang

Wan

et al. 2015

Ann. Geophys.

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“…Of the various parameters, results pertaining to the S 4 and TEC only would be presented and discussed here. The amplitude scintillation index S 4 (Briggs and Parkins, 1963) is given by…”

Section: Methodsmentioning

confidence: 99%

Observations in equatorial anomaly region of total electron content enhancements and depletions

Dashora¹,

Pandey²

2005

Ann. Geophys.

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Abstract.A GSV 4004A GPS receiver has been operational near the crest of the equatorial anomaly at Udaipur, India for some time now. The receiver provides the line-of-sight total electron content (TEC), the phase and amplitude scintillation index, σ φ and S 4 , respectively. This paper presents the first results on the nighttime TEC depletions associated with the equatorial spread F in the Indian zone. The TEC depletions are found to be very well correlated with the increased S 4 index. A new feature of low-latitude TEC is also reported, concerning the observation of isolated and localized TEC enhancements in the nighttime low-latitude ionosphere. The TEC enhancements are not correlated with the S 4 index. The TEC enhancements have also been observed along with the TEC depletions. The TEC enhancements have been interpreted as the manifestation of the plasma density enhancements reported by Le et al. (2003).

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“…Amplitude scintillation is characterized through the S4 parameter (Briggs & Parkin, 1963) which is defined as the normalized standard deviation of the signal intensity: due to diffractive effects, the amplitude of the signals suffers deep fades (decreasing dramatically their C/N 0 ) which can end in a cycle slip of the carrier phase tracking or even a loss of lock. Whereas, phase scintillation is measured trough the s f parameter (Yeh & Chao-Han, 1982), which is the standard deviation of the high frequency fluctuation of the carrier phase.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of precise navigation in high and low latitude regions under scintillation conditions

Zornoza

Sanz

González-Casado

et al. 2018

J. Space Weather Space Clim.

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-Scintillation is one of the most challenging problems in Global Navigation Satellite Systems (GNSS) navigation. This phenomenon appears when the radio signal passes through ionospheric irregularities. These irregularities represent rapid changes on the refraction index and, depending on their size, they can produce also diffractive effects affecting the signal amplitude and, eventually producing cycle slips. In this work, we show that the scintillation effects on the GNSS signal are quite different in low and high latitudes. For low latitude receivers, the main effects, from the point of view of precise navigation, are the increase of the carrier phase noise (measured by s f ) and the fade on the signal intensity (measured by S4) that can produce cycle slips in the GNSS signal. With several examples, we show that the detection of these cycle slips is the most challenging problem for precise navigation, in such a way that, if these cycle slips are detected, precise navigation can be achieved in these regions under scintillation conditions. For high-latitude receivers the situation differs. In this region the size of the irregularities is typically larger than the Fresnel length, so the main effects are related with the fast change on the refractive index associated to the fast movement of the irregularities (which can reach velocities up to several km/s). Consequently, the main effect on the GNSS signals is a fast fluctuation of the carrier phase (large s f ), but with a moderate fade in the amplitude (moderate S4). Therefore, as shown through several examples, fluctuations at high-latitude usually do not produce cycle slips, being the effect quite limited on the ionosphere-free combination and, in general, precise navigation can be achieved also during strong scintillation conditions.

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On the variation of radio star and satellite scintillations with zenith angle

Cited by 365 publications

References 17 publications

A comparative study of GPS ionospheric scintillations and ionogram spread F over Sanya

A comparative study of GPS ionospheric scintillations and ionogram spread F over Sanya

Observations in equatorial anomaly region of total electron content enhancements and depletions

Feasibility of precise navigation in high and low latitude regions under scintillation conditions

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