Analysis of the Regional Ionosphere at Low Latitudes in Support of the Biomass ESA Mission

Alfonsi, Lucilla; Povero, Gabriella; Spogli, Luca; Cesaroni, Claudio; Forte, Biagio; Mitchell, Cathryn N.; Burston, Robert; Veettil, Sreeja Vadakke; Aquino, Márcio; Klausner, Virginia; Muella, M. T. A. H.; Pezzopane, Michael; Giuntini, Alessandra; Hunstad, I.; Franceschi, Giorgiana De; Musicò, Elvira; Pini, Marco; Trung, Hieu Tran; Husin, Asnawi; Ekawati, Sri; Cruz-Cayapan, Charisma Victoria de la; Abdullah, Mardina; Daud, Noridawaty Mat; Minh, Lê Huy; Floury, Nicolas

doi:10.1109/tgrs.2018.2838321

Cited by 7 publications

(7 citation statements)

References 24 publications

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“…According to (15), the Doppler errors can induce an image shift in the azimuth direction, which is signified as (20) where is the ground velocity, defined by…”

Section: ) Geometric Distortion In Azimuth Direction (Azimuth Shift)mentioning

confidence: 99%

“…Eq. (20) states that the azimuth shift no longer follows the proportionality to the first-order gradient of the TEC as a result of the contribution from high order Doppler errors due to background ionospheric effects. Also, the definition of the ground velocity in (21) suggests the Earth's rotation can also impact the azimuth shift.…”

Section: ) Geometric Distortion In Azimuth Direction (Azimuth Shift)mentioning

confidence: 99%

“…Hence, the radio signal is inevitably affected by the ionosphere during the propagation, the extent depending on the radar frequency [7,8]. The ultra-high frequency (UHF), particularly, experiences more adverse effects from the ionosphere; and thus, the imaging performance of the spaceborne SAR operating at UHF is degraded due to the ionospheric effects [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Therefore, it is important to understand those potential effects on the P-band spaceborne SAR imaging before its data can be better used.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study of the Spatiotemporally-Varying Background Ionospheric Effects on P-Band Satellite SAR Imaging

Chen

2020

IEEE Access

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At the relatively low frequency of the P-band spaceborne SAR, the background ionosphere is no longer treated as time-invariant, together with the spatial variation in the background ionosphere, and complicates the spaceborne SAR imaging. In this paper, we systematically quantify the effects of the spatiotemporally varying background ionosphere on the imaging performance of the P-band spaceborne SAR. The signal model for a P-band spaceborne SAR is established in accordance with the range history taking account of the Earth's rotation, based on which the 2-dimensional (2-D) signal frequency spectrum under the influence of spatiotemporally varying background ionosphere is derived. Then, the geometric distortion and defocusing phenomenon in the range and azimuth directions are quantitatively evaluated. It is found that the range shift is mainly determined by the constant component of the background ionosphere, and the contribution from the spatiotemporally varying components of the background ionosphere is nonnegligible. In contrast, the azimuth shift has no dependency on the constant part of the background ionosphere, but both the spatially varying and temporally varying components of the background ionosphere could give rise to considerable azimuth shifts. Regarding the focusing quality, it is seldom impaired by the background ionosphere for the P-band spaceborne SAR with a coarse spatial resolution on a decameter scale. However, the high spatial resolution makes it difficult to maintain good focusing qualities, especially at the high solar activity. Finally, numerical simulations in terms of the single-point target responses confirm the theoretical analysis; simulations of responses of array-point targets, together with 2-D image shifts along the satellite's track, show the disparity of background ionosphere can further affect the imaging performance of the P-band spaceborne SAR. In this respect, effects of spatiotemporally varying background ionosphere deserve special care in the signal processing of a P-band spaceborne SAR. INDEX TERMS P-band spaceborne SAR, spatiotemporally varying, background ionospheric effects, geometric distortion, focusing quality, disparity of background ionosphere.

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“…According to (15), the Doppler errors can induce an image shift in the azimuth direction, which is signified as (20) where is the ground velocity, defined by…”

Section: ) Geometric Distortion In Azimuth Direction (Azimuth Shift)mentioning

confidence: 99%

Section: ) Geometric Distortion In Azimuth Direction (Azimuth Shift)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical Study of the Spatiotemporally-Varying Background Ionospheric Effects on P-Band Satellite SAR Imaging

Chen

2020

IEEE Access

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“…Many different scintillation monitors with multi‐frequency and multi‐constellation possibilities have been developed in the last decade. Devices from different manufacturers have been used in different studies and sometimes data analysis involves using data from different equipments (Alfonsi et al., 2018; de Paula et al., 2019; Fortes et al., 2015). A question that arises is how closely the result of these equipments can agree.…”

Section: Introductionmentioning

confidence: 99%

Performance of 6 Different Global Navigation Satellite System Receivers at Low Latitude Under Moderate and Strong Scintillation

Paula

Martinon

Moraes

et al. 2021

Earth and Space Science

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After sunset, in the equatorial regions ionospheric plasma irregularities are generated due to the generalized Rayleigh‐Taylor instability. Under favorable conditions these irregularities develop in the equatorial region while mapping along the magnetic field lines giving rise to large plasma depletion structures called Equatorial Plasma Bubbles with embedded smaller structures on their walls. The global navigation satellite system (GNSS) L1 band frequency is sensitive to irregularities of the size of 300–400 m in the first Fresnel zone, which cause scattering and diffraction of the signal and produce amplitude and/or phase scintillation. Severe scintillation of GNSS signals can in turn cause loss of lock of the receiver code and/or carrier loops. As a result, GNSS navigation and positioning solution can be adversely affected by the ionospheric scintillation. There are multiple GNSS receivers designed to monitor scintillations. These receivers are based on different hardware designs and use different methodologies to process the raw data. When using simultaneous data from different GNSS scintillation monitors it is important to evaluate and compare their performances under similar scintillation conditions. The scintillation monitoring techniques may be useful for many applications that use GNSS signal. The aim of this work is to evaluate the performance of six different GNSS receivers located at São José dos Campos (23.1°S, 45.8°W, dip latitude 17.3°S) during moderate and strong scintillation activity. The amplitude (S4) and phase (σϕ) scintillation indexes from these receivers were analyzed and compared for the nights February 20–21 and November 27–28, 2013.

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“…time period, horizontal drift velocity and horizontal wavelength. Details of this algorithm are presented in Alfonsi et al (2018).…”

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confidence: 99%

The ionosphere prediction service prototype for GNSS users

Veettil

Cesaroni

Aquino

et al. 2019

J. Space Weather Space Clim.

Self Cite

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The effect of the Earth’s ionosphere represents the single largest contribution to the Global Navigation Satellite System (GNSS) error budget and abnormal ionospheric conditions can impose serious degradation on GNSS system functionality, including integrity, accuracy and availability. With the growing reliance on GNSS for many modern life applications, actionable ionospheric forecasts can contribute to the understanding and mitigation of the impact of the ionosphere on our technology based society. In this context, the Ionosphere Prediction Service (IPS) project was set up to design and develop a prototype platform to translate the forecast of the ionospheric effects into a service customized for specific GNSS user communities. To achieve this overarching aim, four different product groups dealing with solar activity, ionospheric activity, GNSS receiver performance and service performance have been developed and integrated into a service chain, which is made available through a web based platform. This paper provides an overview of the IPS project describing its overall architecture, products and web based platform.

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Analysis of the Regional Ionosphere at Low Latitudes in Support of the Biomass ESA Mission

Cited by 7 publications

References 24 publications

Numerical Study of the Spatiotemporally-Varying Background Ionospheric Effects on P-Band Satellite SAR Imaging

Numerical Study of the Spatiotemporally-Varying Background Ionospheric Effects on P-Band Satellite SAR Imaging

Performance of 6 Different Global Navigation Satellite System Receivers at Low Latitude Under Moderate and Strong Scintillation

The ionosphere prediction service prototype for GNSS users

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