Theoretical Analysis and Verification of Time Variation of Background Ionosphere on Geosynchronous SAR Imaging

Tian, Ye; Hu, Cheng; Dong, Xichao; Zeng, Tao; Li, Teng; Lin, Kate Ching-Ju; Zhang, Xinyu

doi:10.1109/lgrs.2014.2360235

Cited by 42 publications

(21 citation statements)

References 9 publications

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“…Considering that the designed frequency bandwidth of GEO SAR is about 20 MHz under the moderate resolution of 20 m and the variation of TEC is generally smaller than 100 TECU in natural conditions, dispersion in range could be ignored [25]. Thus, after imaging processing in the time domain, we have…”

Section: Geo D-insar Signal Model In the Presence Of The Temporal-spamentioning

confidence: 99%

“…As the azimuth shift of each SAR image is proportional to the temporal first-order derivative of TEC with respect to the azimuth time [25], the relative azimuth shift of the InSAR pair ∆a can be expressed as:…”

Section: Relative Image Shift and The Decorrelation Of The Insar Pairmentioning

confidence: 99%

“…Therefore, the ionosphere temporal-spatial frozen model is invalid for the analysis of the impacts of background ionosphere variation on D-InSAR processing in a GEO SAR case. In addition, although some researches have applied the temporal-spatial background ionosphere variation model in previous studies, they mainly focus on the analysis of the impacts of the ionosphere on GEO SAR imaging [1,25,26]. Considering the above reasons, impacts of the temporal-spatial variant ionosphere on the deformation retrieval in GEO D-InSAR need to be specially considered.…”

Section: Introductionmentioning

confidence: 99%

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Impacts of Temporal-Spatial Variant Background Ionosphere on Repeat-Track GEO D-InSAR System

Dong

et al. 2016

Remote Sensing

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An L band geosynchronous synthetic aperture radar (GEO SAR) differential interferometry system (D-InSAR) will be obviously impacted by the background ionosphere, which will give rise to relative image shifts and decorrelations of the SAR interferometry (InSAR) pair, and induce the interferometric phase screen errors in interferograms. However, the background ionosphere varies within the long integration time (hundreds to thousands of seconds) and the extensive imaging scene (1000 km levels) of GEO SAR. As a result, the conventional temporal-spatial invariant background ionosphere model (i.e., frozen model) used in Low Earth Orbit (LEO) SAR is no longer valid. To address the issue, we firstly construct a temporal-spatial background ionosphere variation model, and then theoretically analyze its impacts, including relative image shifts and the decorrelation of the GEO InSAR pair, and the interferometric phase screen errors, on the repeat-track GEO D-InSAR processing. The related impacts highly depend on the background ionosphere parameters (constant total electron content (TEC) component, and the temporal first-order and the temporal second-order derivatives of TEC with respect to the azimuth time), signal bandwidth, and integration time. Finally, the background ionosphere data at Isla Guadalupe Island (29.02 • N, 118.27 • W) on 7-8 October 2013 is employed for validating the aforementioned analysis. Under the selected background ionosphere dataset, the temporal-spatial background ionosphere variation can give rise to a relative azimuth shift of dozens of meters at most, and even the complete decorrelation in the InSAR pair. Moreover, the produced interferometric phase screen error corresponds to a deformation measurement error of more than 0.2 m at most, even in a not severely impacted area.

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Section: Geo D-insar Signal Model In the Presence Of The Temporal-spamentioning

confidence: 99%

Section: Relative Image Shift and The Decorrelation Of The Insar Pairmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impacts of Temporal-Spatial Variant Background Ionosphere on Repeat-Track GEO D-InSAR System

Dong

et al. 2016

Remote Sensing

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“…It has been indicated that the presence of correlated Gaussian noise was employed to characterize the ionospheric temporaldecorrelation in GEO SAR system [8]. Polynomial approximation was applied to analyze the effect of temporal variations of the background ionosphere [9][10][11][12]. Based on this method, an in-depth analysis of the temporal variation of the background ionosphere on GEO SAR imaging was conducted [13].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Background Ionospheric Effects on Geosynchronous SAR Imaging

Zhang¹,

Ji²,

Dong³

et al. 2017

RADIOENGINEERING

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Background ionospheric propagation effects are adverse to the performance of Geosynchronous Synthetic Aperture Radar (GEO SAR) system. This paper focuses on the background ionospheric phase advance, which can be modelled as a function of slant total electron content (STEC). The dispersive feature of the phase advance caused by the background ionosphere could be able to distort the GEO SAR range-imaging. Furthermore, for GEO SAR, the integration time is ultra-long and the coverage is ultra-large, thus temporal and spatial distributions of the background ionosphere have to be taken into account. The resultant ionospheric phase variations might decorrelate the azimuth signal and then lead to azimuthimaging deteriorations. In this paper, the theoretical model of the background ionospheric effects on GEO SAR imaging is established and in-depth analyses are presented. Finally, theoretical analyses are validated by the signallevel simulation.

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“…According to the characteristics of ionosphere, its related disturbances are divided into background ionospheric disturbance and ionospheric scintillation disturbance [5]. Some research about background ionospheric disturbance on GEO SAR were done in [6], but the impacts of ionospheric scintillation on GEO SAR were rarely mentioned. In this paper, both phase and amplitude scintillation is considered to construct the GEO SAR signal model in presence of ionospheric scintillation.…”

Section: Introductionmentioning

confidence: 99%

Impacts of ionospheric scintillation on geosynchronous SAR

Dong

et al. 2015

2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

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Geosynchronous Synthetic Aperture Radar (GEO SAR) will be affected by ionosphere scintillation inevitably because it usually works at L band. In this paper, GEO SAR signal model in presence of ionospheric scintillation is proposed. The scintillation sampling model is employed to simulate ionospheric scintillation data. Several GEO SAR imaging simulations in different scintillation cases and a real ionospheric scintillation measurement in Zhuhai district of China are conducted to study the impacts of ionospheric scintillation on GEO SAR in azimuth. The results suggest that ionospheric scintillation will worsen the azimuth resolution, and rise azimuth peak sidelobe ratio (PSLR), and severely deteriorate azimuth integrated sidelobe ratio (ISLR).

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Theoretical Analysis and Verification of Time Variation of Background Ionosphere on Geosynchronous SAR Imaging

Cited by 42 publications

References 9 publications

Impacts of Temporal-Spatial Variant Background Ionosphere on Repeat-Track GEO D-InSAR System

Impacts of Temporal-Spatial Variant Background Ionosphere on Repeat-Track GEO D-InSAR System

Analysis of Background Ionospheric Effects on Geosynchronous SAR Imaging

Impacts of ionospheric scintillation on geosynchronous SAR

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