Mitigation of higher order ionospheric effects on GNSS users in Europe

Hoque, Mohammed Mainul; Jakowski, N.

doi:10.1007/s10291-007-0069-5

Cited by 49 publications

(49 citation statements)

References 23 publications

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“…Inside the ray tracing program, the IGRF model has been used to compute cos B Θ along ray paths. For details and values of the polynomial coefficients we refer to Hoque & Jakowski (2007). Using such a correction formula and knowing the TEC value, the second order term can be corrected to the 2-3 millimeter accuracy level for a vertical TEC level of 100 TEC units.…”

Section: Second Order Term Correctionmentioning

confidence: 99%

Ionospheric Propagation Effects on GNSS Signals and New Correction Approaches

Hoque¹,

Jakowski²

2012

Global Navigation Satellite Systems: Signal, Theory and Applications

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Section: Second Order Term Correctionmentioning

confidence: 99%

Ionospheric Propagation Effects on GNSS Signals and New Correction Approaches

Hoque¹,

Jakowski²

2012

Global Navigation Satellite Systems: Signal, Theory and Applications

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“…To study the impact of second-order ionospheric delay in a quantitative way, Hoque and Jakowski [10] amended the integration equation (2) as follows:…”

Section: Modified Hoque Modelmentioning

confidence: 99%

“…So the simplified model cannot meet requirements for second-order correction in high accuracy applications. To quantitatively analyze second-order correction of ionospheric delay, Mainul Hoque and Jakowski et al [9,10] studied distribution characteristics of ionospheric second-order corrections with respect to different elevation and azimuth values in different areas around the globe. Furthermore, a correction equation for calculating the average value of geomagnetic field's radial component in signal propagation direction, and an ionospheric second-order correction equation applicable to GNSS users in European region (German in particular) were proposed in 2007 and 2008.…”

Section: Introductionmentioning

confidence: 99%

Global modeling 2nd-order ionospheric delay and its effects on GNSS precise positioning

Zhang

et al. 2011

Sci. China Phys. Mech. Astron.

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Ionospheric delay is one of the major error sources in GNSS navigation and positioning. Nowadays, the dual-frequency technique is the most widely used in ionospheric refraction correction. However, dual-frequency measurements can only eliminate the first-order term of ionospheric delay, while the effect of the second-order term on GNSS observations may be several centimeters. In this paper, two models, the International Reference Ionosphere (IRI) 2007 and International Geomagnetic Reference Field (IGRF) 11 are used to estimate the second-order term through the integral calculation method. Besides, the simplified single layer ionosphere model in a dipole moment approximation for the earth magnetic field is used. Since the traditional integral calculation method requires large calculation load and takes much time, it is not convenient for practical use. Additionally, although the simplified single layer ionosphere model is simple to implement, it results in larger errors. In this study, second-order term ionospheric correction formula proposed by Hoque (2007) is improved for estimating the second-order term at a global scale. Thus, it is more practicable to estimate the second-order term. More importantly, its results have a higher precision of the sub-millimeter level for a global scale in normal conditions. Compared with Hoque's original regional correction model, which calculates coefficients through polynomial fitting of elevation and latitudes, this study proposes a piece-wise look-up table and interpolation technique to modify Hoque model. Through utilizing a table file, the modified Hoque model can be conveniently implemented in an engineering software package, like as PANDA in this study. Through applying the proposed scheme for the second-order ionospheric correction into GNSS precise positioning in both PPP daily and epoch solutions, the results have shown south-shift characteristics in daily solution at a global scale and periodic change with VTEC daily variation in epoch positioning solution.ionospheric delay, second-order ionospheric correction, GNSS precise positioning PACS:

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“…However, for the I 2 -induced deviations of station coordinate estimates under the influence of the Earth's magnetic field, if there exits certain regularity? In order to further investigate the effect of the Earth's magnetic filed on I 2 , it is assumed that the vertical total electron content of all PPP is 100 TECU [8] and the zenith angle is set to 16 values from 0°−75° at a 5° interval. Figure 4 illustrates the variation of I 2 over Wuhan area on April 9, 2003, in which only Earth's magnetic field is concerned.…”

Section: Variations Of I 2 Over Wuhan Area and Its Effect On Gps Posimentioning

confidence: 99%

Model analysis method (MAM) on the effect of the second-order ionospheric delay on GPS positioning solution

et al. 2010

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In this paper, we develop an approach to study the effect of second-order ionospheric delay on GPS positioning based on the ionosphere-free combination (abbreviated to Lc) of GPS dual-frequency carrier phase observables, in which the first-order ionospheric delay has been eliminated. GPS data from IGS WUHN tracking station during April 9−23, 2003 is used to perform the above approach, and results show that the second-order ionospheric delay in GPS so-called ionosphere-free observables will result in the regular southward shift of GPS positioning solution. Additionally, the influence of the Earth's magnetic field on second-order ionospheric delay over the Wuhan area is discussed, and it indicates that the Earth's magnetic field is one of the main factors why second-order ionospheric delay results in the regular southward shift of GPS positioning solution over Wuhan area. Global Positioning System (GPS), second-order ionospheric delay (I 2 ), total electron content (TEC), GPS positioning, international geomagnetic reference field 10 (IGRF10) Citation:Liu X F, Yuan Y B, Huo X L, et al. Model analysis method (MAM) on the effect of the second-order ionospheric delay on GPS positioning solution. .g. modernized GPS), GNSS has been widely used in various applications in the past few decades. However, the ionosphere is still one of the major error resources for GNSS. Although the ionosphere-free combinations of GPS observables have been used to weaken the effects of ionosphere, this method only eliminates the effects of first-order ionospheric delay in GPS signal. As multi-frequency GNSS technology develops quickly, the linear combinations of tri-frequency GNSS data can be used to directly eliminate the first-order and second-order ionospheric terms in theory, but the noise of tri-frequency combination will be accordingly magnified several tens of times more than undifferenced GPS observable noise and is larger than the order of second-order ionospheric delay. It is therefore unfeasible in practice [1−4]. In recent years, the effects of higher-order ionospheric delay (mainly second-order) on precise GNSS positioning solution had been paid more attention in high-precision GNSS geodetic areas [5−10], such as crust deformation monitoring, earthquake disaster forecasting, plate movement and other related research and application areas. Researches show that the effect of I 2 on GPS positioning could be of the order of few centimeters. Thereafter, how to effectively weaken or even eliminate the effect of I 2 is one of the key issues in achieving higher than either cm-level absolute positioning or mm-level relative positioning in high-precision applications. Up to now, many efforts have been made to estimate the effect of I 2 on GPS positioning through a lot of GPS data processing, and the results showed that I 2 would result in a regular shift of GPS positioning solution [7−10]. But nobody gives a reasonable interpretation for this phenomenon. In China, there are still few relevant investigation reports currently.In this contri...

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Mitigation of higher order ionospheric effects on GNSS users in Europe

Cited by 49 publications

References 23 publications

Ionospheric Propagation Effects on GNSS Signals and New Correction Approaches

Ionospheric Propagation Effects on GNSS Signals and New Correction Approaches

Global modeling 2nd-order ionospheric delay and its effects on GNSS precise positioning

Model analysis method (MAM) on the effect of the second-order ionospheric delay on GPS positioning solution

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