L-band geosynchronous SAR imaging degradations imposed by ionospheric irregularities

2017 ◽  
Vol 60 (6) ◽  
Author(s):  
Yifei Ji ◽  
Qilei Zhang ◽  
Yongsheng Zhang ◽  
Zhen Dong
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Soni Darmawan ◽  
Ita Carolita ◽  
Rika Hernawati ◽  
Dede Dirgahayu ◽  
Agustan ◽  
...  

Information about oil palm phenology is required for oil palm plantation management, but using spaceborne polarimetric radar imagery remains challenging. However, spaceborne polarimetric radar on X-, C-, and L-band is promising on structure vegetation and cloud area. This study investigates the scattering model of oil palm phenology based on spaceborne X-, C-, and L-band polarimetric Synthetic Aperture Radar (SAR) imaging. The X-, C-, and L-band polarimetric SAR are derived from spaceborne of TerraSAR-X, Sentinel-1A, and ALOS PALSAR 2. Study area is located in oil palm plantations, Asahan District, North Sumatra, Indonesia. The methodology includes data collection, preprocessing, radiometric calibration, speckle filtering, terrain correction, extraction of scattering value, and development of scattering model of oil palm phenology. The results showed different scattering characteristics for the X-, C-, and L-band polarimetric SAR of oil palm for age and found the potential of the scattering model for oil palm phenology based on the X-band on HH polarization that showed a nonlinear model with R 2 = 0.65 . The C-band on VH and VV polarization showed a nonlinear model with R 2 = 0.56 and R 2 = 0.89 . The L-band on HV and HH polarization showed a logarithmic model with R 2 = 0.50 and R 2 = 0.51 . In this case, the most potential of the scattering model of oil palm phenology based on R 2 is using C-band on VV polarization. However, the scattering model based on X-, C-, and L-band is potentially to be used and applied to identify the phenology of oil palm in Indonesia, which is the main parameter in yield estimation. For the future phenology model needs to improve accuracy by integrating multisensors, including different wavelengths on optical and microwave sensors and more in situ data.


2020 ◽  
Vol 58 (8) ◽  
pp. 5516-5526
Author(s):  
Yifei Ji ◽  
Qilei Zhang ◽  
Yongsheng Zhang ◽  
Zhen Dong ◽  
Baidong Yao

2013 ◽  
Vol 7 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Leilei Kou ◽  
Maosheng Xiang ◽  
Xiaoqing Wang ◽  
Minhui Zhu
Keyword(s):  

2017 ◽  
Vol 55 (1) ◽  
pp. 159-172 ◽  
Author(s):  
Cheng Hu ◽  
Yuanhao Li ◽  
Xichao Dong ◽  
Rui Wang ◽  
Dongyang Ao

2020 ◽  
Vol 58 (6) ◽  
pp. 3941-3954
Author(s):  
Yifei Ji ◽  
Yongsheng Zhang ◽  
Zhen Dong ◽  
Qilei Zhang ◽  
Dexin Li ◽  
...  

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Sharon Aol ◽  
Stephan Buchert ◽  
Edward Jurua

Abstract Ionospheric irregularities can affect satellite communication and navigation by causing scintillations of radio signals. The scintillations are routinely measured using ground-based networks of receivers. This study presents observations of ionospheric irregularities by Langmuir probes on the Swarm satellites. They are compared with amplitude scintillation events recorded by the Global Positioning System-Scintillation Network and Decision Aid (GPS-SCINDA) receiver installed in Mbarara (Lat: $$0.6^{\circ }\hbox {S}$$ 0 . 6 ∘ S , Lon: $$30.8^{\circ }\hbox {E}$$ 30 . 8 ∘ E , Mag. lat: $$10.2^{\circ }\hbox {S}$$ 10 . 2 ∘ S ). The study covers the years from 2014 to 2018 when both data sets were available. It was found that the ground-based amplitude scintillations were enhanced when Swarm registered ionospheric irregularities for a large number of passes. The number of matching observations was greater for Swarm A and C which orbited at lower altitudes compared to Swarm B. However, some counterexamples, i.e., cases when in situ electron density fluctuations were not associated with any observed L-band amplitude scintillation and vice versa, were also found. Therefore, mismatches between observed irregularity structures and scintillations can occur just over a few minutes and within distances of a few tens of kilometers. The amplitude scintillation strength, characterized by the S4 index was estimated from the electron density data using the well-known phase screen model for weak scattering. The derived amplitude scintillation was on average lower for Swarm B than for A and C and less in accordance with the observed range. Irregularities at an altitude of about 450 km contribute strongly to scintillations in the L-band, while irregularities at about 510-km altitude contribute significantly less. We infer that in situ density fluctuations observed on passes over or near Mbarara may be used to indicate the risk that ionospheric radio wave scintillations occur at that site.


2014 ◽  
Vol 62 (9) ◽  
pp. 4664-4673 ◽  
Author(s):  
Cheng Wang ◽  
Min Zhang ◽  
Zheng-Wen Xu ◽  
Chun Chen ◽  
Dong-Sheng Sheng

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