Analysis of ionospheric contributions to the Doppler shift of CW signals from artificial Earth satellites

Tucker, A. J.; Fannin, B. M.

doi:10.1029/ja073i013p04325

Cited by 15 publications

(4 citation statements)

References 16 publications

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“…Brunner and Gu [1991] retain the first four terms by order of magnitude considerations. Tucker and Fannin [1968] additionally retain the cosine terms by making a quasi‐longitudinal approximation (i.e. θ = 0).…”

Section: Introductionmentioning

confidence: 99%

Bounding higher‐order ionosphere errors for the dual‐frequency GPS user

et al. 2008

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[1] Civil signals at L2 and L5 frequencies herald a new phase of Global Positioning System (GPS) performance. Dual-frequency users typically assume a first-order approximation of the ionosphere index of refraction, combining the GPS observables to eliminate most of the ranging delay, on the order of meters, introduced into the pseudoranges. This paper estimates the higher-order group and phase errors that occur from assuming the ordinary first-order dual-frequency ionosphere model using data from the Federal Aviation Administration's Wide Area Augmentation System (WAAS) network on a solar maximum quiet day and an extremely stormy day postsolar maximum. We find that during active periods, when ionospheric storms may introduce slant range delays at L1 as high as 100 m, the higher-order group errors in the L1-L2 or L1-L5 dual-frequency combination can be tens of centimeters. The group and phase errors are no longer equal and opposite, so these errors accumulate in carrier smoothing of the dualfrequency code observable. We show the errors in the carrier-smoothed code are due to higher-order group errors and, to a lesser extent, to higher-order phase rate errors. For many applications, this residual error is sufficiently small as to be neglected. However, such errors can impact geodetic applications as well as the error budgets of GPS Augmentation Systems providing Category III precision approach.

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Section: Introductionmentioning

confidence: 99%

Bounding higher‐order ionosphere errors for the dual‐frequency GPS user

et al. 2008

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“…[4] Even though several authors have considered the effects of higher-order ionospheric terms on radio signals [e.g., Tucker and Fannin, 1968;Clynch and Renfro, 1982;Ajayi et al, 1980;Brunner and Gu, 1991;Bassiri and Hajj, 1993], none have considered the implication of higher-order ionospheric terms on ground station position accuracies. In this study we investigate the effects of the 2nd-order ionospheric term on GPS inferred station position by implementing a correction suggested by Bassiri and Hajj [1993].…”

Section: Introductionmentioning

confidence: 99%

The effect of the second order GPS ionospheric correction on receiver positions

Kedar

Hajj

Wilson

et al. 2003

Geophysical Research Letters

211

199

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[1] The Global Positioning System (GPS) transmits two frequencies, allowing users to correct for the first-order ionospheric signal group delay (or phase advance) of 1 -50 m. The second-order ionospheric term, caused by the Faraday rotation effect induced by the Earth magnetic field, is about 1000 times smaller and usually ignored. In this study, we implement the 2nd-order correction suggested by Bassiri and Hajj [1993] and investigate its effect on GPSinferred station positions. The correction causes a latitude dependent $0.1-0.5 cm southward shift to the position which is roughly proportional to the integrated electron density above the receiver, and has strong diurnal, seasonal and decadal signatures. By analyzing a three-year time series of equatorial station positions obtained without the 2nd-order correction, a strong semi-annual north-south oscillation is observed, the origin of which has not been hitherto explained. We verify that this apparent oscillation can be largely removed once the 2nd-order correction is applied.

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“…-1 A stability of 1 p a r t in lo1' in the oscillator is equivalent t o 3 c m s e c and t h e r e is abundant evidence that the Doppler data can be acquired to an a c c u r a c y of 1 to 2 cm s e c ionospheric effects (Willman and Tucker, 1968;Tucker and Fannin, 1968; B e r b e r t , Applied Physics Laboratory, 1968).…”

Section: Introductionmentioning

confidence: 99%