Article
Engineering, Electrical & Electronic
Simon H. Yueh, Rashmi Shah, Xiaolan Xu, Bryan Stiles, Xavier Bosch-Lluis
Summary: The study analyzed the spaceborne aperture radar (SAR) technique based on a combination of signals from the United States Navy's Mobile User Objective System and P-hand signals of opportunity with a sparse array of receivers at low earth orbits. The design focused on forward-looking geometry near the specular direction to achieve high surface reflectivity and adequate signal-to-noise ratio. Utilizing a sparse array sharpened the resolution, reduced ambiguity, and showed promise for high-resolution remote sensing of land surfaces.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2021)
Article
Geochemistry & Geophysics
Hongyang An, Junjie Wu, Kah Chan Teh, Zhichao Sun, Zhongyu Li, Jianyu Yang
Summary: This article proposes an efficient video formation method for video SAR systems with reduced data, modeling the observed scene as a sum of low-rank and sparse tensors and using a tensor alternating direction method of multiplier. Compared to traditional imaging methods, the proposed approach greatly reduces the amount of data samples.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Engineering, Electrical & Electronic
Yuri Alvarez Lopez, Jaime Laviada, Ana Arboleya, Fernando Las-Heras
Summary: Synthetic aperture radar (SAR)-based microwave imaging systems are widely used in various applications. The scanning speed is a crucial factor in SAR imaging systems, and widening the distance between measurements can increase it. However, this causes the presence of grating lobes that degrade the quality of microwave SAR images. To address this issue, a novel methodology is proposed in this study, which incorporates the amplitude and phase of the field radiated by the transmitting and receiving antennas in the backpropagation imaging algorithm. This method exploits the directive pattern of the antennas to reduce the level of grating lobes in SAR images.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Geochemistry & Geophysics
Yijiang Nan, Xiaojing Huang, Y. Jay Guo
Summary: This article proposes a new panoramic SAR which combines linear and rotational SARs to reconstruct a large 360 degrees panoramic view of the observed scene. It introduces the system geometry, imaging process, resolution analysis, sampling criteria, and a novel dynamic piecewise compensation algorithm. A prototype of panoramic SAR is built based on an FMCW radar and a moving platform, and simulation and experimental results are provided to validate the proposed principle and algorithm.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Remote Sensing
Kai Zhao, Yan Zhou, Xin Chen, Bing Wang, Yong Zhang
Summary: Research on ship detection in Synthetic Aperture Radar (SAR) images has led to the development of a detector that does not require pre-training, using a unique network structure and feature handling strategy to successfully address the detection of small and multi-scale targets.
INTERNATIONAL JOURNAL OF REMOTE SENSING
(2021)
Article
Engineering, Electrical & Electronic
Chao Liu, Mohammad Tayeb Al Qaseer, Reza Zoughi
Summary: The proposed method extracts complex permittivity from SAR images of multilayered structures by compensating for various issues through calibration and optimization processes, showing potential for accurate nondestructive evaluation purposes.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Geosciences, Multidisciplinary
Jianjun Wang, Fei Wu, Jiali Shang, Qi Zhou, Irshad Ahmad, Guisheng Zhou
Summary: This study investigates the potential of using Sentinel-1A SAR imagery and Machine Learning Algorithms for soil moisture (SM) mapping in China's east coast. The newly developed SVR model provides more accurate SM estimation than the RFR and MLR models, and can effectively map SM even without information on soil surface roughness, soil salinity, and land cover types.
Article
Geochemistry & Geophysics
Marwan Younis, Felipe Queiroz de Almeida, Tobias Bollian, Michelangelo Villano, Gerhard Krieger, Alberto Moreira
Summary: This article describes the frequency scan for time-of-echo compression (f-STEC) imaging technique in synthetic aperture radar (SAR), providing detailed analysis of the technique and deriving analytic expressions for the f-STEC timing constraints for the first time. The performance and feasibility of the f-STEC technique are reported and compared to conventional and modern imaging modes, showing its specific advantages for SAR systems operating at higher carrier frequencies or as an attractive add-on for state-of-the-art SAR instruments.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Environmental Sciences
Pei Zhan, Wenquan Zhu, Nan Li
Summary: The researchers proposed an automated rice mapping method called ARM-SARFS based on Sentinel-1A data, which has high accuracy and is not sensitive to thresholds. Validation results show that ARM-SARFS exhibits high classification accuracy under different rice cropping systems and geographical-climatic conditions, with significant improvements compared to previous methods.
REMOTE SENSING OF ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Maxwell Nogueira Peixoto, Michelangelo Villano
Summary: Synthetic aperture radar (SAR) is a high-resolution imaging radar used in satellite remote sensing, with staggered SAR being a novel mode of operation under consideration for future SAR missions. Proposed processing techniques aim to mitigate the impact of nadir echoes in staggered SAR images and recover useful signals through interpolation, leading to improved image quality at a reasonable additional computational cost.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2022)
Article
Geochemistry & Geophysics
Xinhua Mao, Tianyue Shi, Ronghui Zhan, Yu-Dong Zhang, Daiyin Zhu
Summary: This article presents a new interpretation of the polar format algorithm for general bistatic spotlight synthetic aperture radar imaging, analyzing the roles of range and azimuth resampling on residual 2-D phase error and proposing a structure-aided 2-D autofocus approach to improve accuracy. Experimental results demonstrate the effectiveness of the proposed approach.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2021)
Article
Remote Sensing
Felipe M. Santos, Andre L. C. Santos, Nelson Violante-Carvalho, Luiz Mariano Carvalho, Yuri O. Brasil-Correa, Jesus Portilla-Yandun, Roland Romeiser
Summary: The study presents a method to simulate SAR image spectra of ocean swell waves, evaluating the impact of parameters settings and input information on the relationship between SAR image spectra and wave spectra. Useful information about the processes involved in the imaging of ocean swells can be derived from the SAR simulator.
INTERNATIONAL JOURNAL OF REMOTE SENSING
(2021)
Article
Engineering, Electrical & Electronic
Takuma Watanabe, Hiroyoshi Yamada
Summary: This study proposes a synthetic aperture imaging technique for near-field scatterers mutually coupled with an antenna array, aiming to reduce unwanted scattered and reradiated waves, and validate the antenna design using bistatic synthetic aperture radar measurement. A direct wave filter is applied as a preprocessing method to suppress artifacts caused by direct waves in image reconstruction.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2021)
Article
Geochemistry & Geophysics
Omkar Pradhan, Albin J. Gasiewski
Summary: This paper presents an endfire synthetic aperture radar (SAR) designed for a cylindrical ice-penetrating cryobot. The SAR is used to detect and map obstacles inside ice for subsurface exploration. The unique feature of this system is the use of paired antennas with fixed baselines to implement multiple coherent monostatic SARs for 3D target position estimation. Experimental validation of the SAR's performance is presented, including radar signal coherency tests and point target estimation.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Geochemistry & Geophysics
Wei Xu, Weida Xing, Chonghua Fang, Pingping Huang, Weixian Tan
Summary: The article proposes a modified two-step notch filtering approach combined with linear prediction to improve the SAR image quality. This method effectively mitigates narrowband RFI energy while recovering missing range spectral components.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2021)
Article
Remote Sensing
Ayoob Karami, Hamid Reza Moradi, Alijafar Mousivand, Albert I. J. M. van Dijk, Luigi Renzullo
Summary: This study presents a framework for disaggregating SMAP enhanced soil moisture using random forest regression and ancillary data. The downscaled soil moisture product overcame limitations in spatial resolution and cloudiness effects, showing improved local heterogeneity and tracking temporal changes in soil moisture. Validation results demonstrated the usefulness of the proposed methodology in downscaling the medium-resolution SMAP soil moisture product.
INTERNATIONAL JOURNAL OF REMOTE SENSING
(2022)
Article
Remote Sensing
Alena Dostalova, Claudio Navacchi, Isabella Greimeister-Pfeil, David Small, Wolfgang Wagner
Summary: This study quantified the influence of radiometric terrain flattening (RTF) on forest mapping and classification over Austria, and found that it improved the overall accuracy of mapping and classification, with stronger effects in regions with steep topography.
REMOTE SENSING LETTERS
(2022)
Article
Environmental Sciences
Bernhard Bauer-Marschallinger, Senmao Cao, Mark Edwin Tupas, Florian Roth, Claudio Navacchi, Thomas Melzer, Vahid Freeman, Wolfgang Wagner
Summary: By utilizing the systematic monitoring schedule and global land coverage of the Copernicus Sentinel-1 SAR mission, along with a priori generated probability parameters, we developed a datacube-based flood mapping algorithm to enhance the accuracy and robustness of fully automated flood monitoring and classification.
Article
Remote Sensing
Keith Morrison, Wolfgang Wagner
Summary: This study explores a remote sensing method for measuring soil moisture and depth in low-moisture environments. By analyzing the phase changes of radar waves propagating through the soil, a Phase Scaled Dielectric (PSD) model is developed to estimate the volumetric moisture fraction of the soil. Experimental validation demonstrates the feasibility of this method, offering a new avenue for radar remote sensing applications.
CANADIAN JOURNAL OF REMOTE SENSING
(2022)
Article
Geography, Physical
Claudio Navacchi, Senmao Cao, Bernhard Bauer-Marschallinger, Paul Snoeij, David Small, Wolfgang Wagner
Summary: This paper discusses the methods of generating backscatter datacubes using the Sentinel-1 mission, introduces a simplified workflow relying on its orbital stability, and proposes some improvements to speed up processing and reduce computational costs.
ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
(2022)
Article
Environmental Sciences
Xu Shan, Susan Steele-Dunne, Manuel Huber, Sebastian Hahn, Wolfgang Wagner, Bertrand Bonan, Clement Albergel, Jean-Christophe Calvet, Ou Ku, Sonja Georgievska
Summary: In this study, a deep neural network model was used to estimate the parameters of ASCAT C-band microwave scattering, and the model was trained and validated in France. The sensitivity of ASCAT observables to land surface variables was also investigated. The results showed that the DNN model performed well in predicting and reproducing the scattering characteristics of ASCAT, and indicated that soil moisture, vegetation index, and land cover type had significant impacts on ASCAT observations.
REMOTE SENSING OF ENVIRONMENT
(2022)
Article
Environmental Sciences
Paolo Filippucci, Luca Brocca, Stefania Bonafoni, Carla Saltalippi, Wolfgang Wagner, Angelica Tarpanelli
Summary: River monitoring is a challenging issue, but the use of satellite sensors, such as those from Sentinel-2, has greatly improved river discharge estimation. This study investigates the potential of Sentinel-2 NIR reflectances in improving river discharge estimation and evaluates its accuracy using in-situ observations from Italian rivers. The results demonstrate the effectiveness of high-resolution images in estimating river discharges.
REMOTE SENSING OF ENVIRONMENT
(2022)
Article
Environmental Sciences
Kai Wu, Dongryeol Ryu, Wolfgang Wagner, Zhongmin Hu
Summary: This study aims to advance the use of Triple Collocation Analysis (TCA) for characterizing errors in remotely sensed soil moisture data, particularly focusing on the impact of rescaling techniques and the validation of TCA-based time-variant errors. The findings suggest that different selection of rescaling techniques significantly affects the accuracy of TCA error estimates. The optimal combination strategy is to apply TCA to soil moisture anomalies and rescale errors using coefficients derived from the TCA model. The study highlights the importance of accurate characterization of errors for hydrometeorological applications.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Environmental Sciences
Mark Edwin Tupas, Florian Roth, Bernhard Bauer-Marschallinger, Wolfgang Wagner
Summary: With the help of Sentinel-1 mission, the study compared four change detection models and found that the Bayes change detection model performed the best in terms of mapping accuracy due to its scalable classification rules and least sensitivity to parameter choices.
Article
Chemistry, Analytical
Claudio Navacchi, Senmao Cao, Bernhard Bauer-Marschallinger, Paul Snoeij, David Small, Wolfgang Wagner
Summary: Radiometric Terrain Corrected (RTC) gamma nought backscatter has become the standard for analysis-ready SAR data. However, processing large SAR datasets requires substantial computing resources.
Article
Multidisciplinary Sciences
Hylke E. Beck, Tim R. Mcvicar, Noemi Vergopolan, Alexis Berg, Nicholas J. Lutsko, Ambroise Dufour, Zhenzhong Zeng, Xin Jiang, Albert I. J. M. van Dijk, Diego G. Miralles
Summary: This study introduces Version 2 of the widely used 1-km Koppen-Geiger climate classification maps, which include historical and future climate conditions. The maps are based on high-resolution observation data and climate projections. The results show that approximately 5% of the global land surface has transitioned to a different major climate class in the past, and this proportion is projected to increase in the future under different emissions scenarios.
Article
Environmental Sciences
Hyunglok Kim, Wade Crow, Xiaojun Li, Wolfgang Wagner, Sebastian Hahn, Venkataraman Lakshmi
Summary: This article discusses the importance of quantifying the accuracy of satellite-based soil moisture data and the limitations of existing statistical methods. It then fills the spatial gaps in TCA results using machine learning and provides spatially complete error maps for satellite-based soil moisture data products. Additionally, SHAP values are used to examine the impact of various environmental conditions on the quality of satellite-based soil moisture retrievals.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Forestry
Sami Ullah Shah, Marta Yebra, Albert I. J. M. Van Dijk, Geoffrey J. Cary
Summary: The study found a positive correlation between fire danger classes and burned area in Australia's inland regions, but elevated fire danger classes did not contribute to this trend. In coastal regions, there was no relationship between fire danger classes and burned area.
INTERNATIONAL JOURNAL OF WILDLAND FIRE
(2023)
Proceedings Paper
Geosciences, Multidisciplinary
Isabella Greimeister-Pfeil, Mariette Vreugdenhil, Wolfgang Preimesberger, Luca Brocca, Stefania Camici, Markus Enenkel, Antoine Bavandi, Wolfgang Wagner
Summary: This study analyzes the potential of using satellite-based datasets to track rainfall deficits through the water cycle, showing that satellite-derived soil moisture can bridge the gap between rainfall deficits and negative impacts on vegetation, allowing for early warning of developing food crises.
2022 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2022)
(2022)
Article
Geosciences, Multidisciplinary
Jiawei Hou, Albert I. J. M. van Dijk, Hylke E. Beck, Luigi J. Renzullo, Yoshihide Wada
Summary: Large dam reservoirs have been constructed worldwide to increase water supplies and support economic growth. Using remote sensing technology, the monthly water storage of 6695 reservoirs between 1984 and 2015 was reconstructed. It was found that 23% of reservoirs experienced significant decreases in storage, while 21% experienced increases. These changes were primarily influenced by precipitation and river inflow, highlighting the importance of long-term precipitation changes for reservoir water storage.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2022)
Article
Environmental Sciences
Ruonan Chen, Liangyun Liu, Xinjie Liu, Zhunqiao Liu, Lianhong Gu, Uwe Rascher
Summary: This study presents methods to accurately estimate sub-daily GPP from SIF in evergreen needleleaf forests and demonstrates that the interactions among light, canopy structure, and leaf physiology regulate the SIF-GPP relationship at the canopy scale.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Daniel L. Goldberg, Madankui Tao, Gaige Hunter Kerr, Siqi Ma, Daniel Q. Tong, Arlene M. Fiore, Angela F. Dickens, Zachariah E. Adelman, Susan C. Anenberg
Summary: A novel method is applied in this study to directly use satellite data to evaluate the spatial patterns of urban NOx emissions inventories. The results show that the 108 spatial surrogates used by NEMO are generally appropriate, but there may be underestimation in areas with dense intermodal facilities and overestimation in wealthy communities.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Zhuoyue Hu, Xiaoyan Li, Liyuan Li, Xiaofeng Su, Lin Yang, Yong Zhang, Xingjian Hu, Chun Lin, Yujun Tang, Jian Hao, Xiaojin Sun, Fansheng Chen
Summary: This paper proposes a whisk-broom imaging method using a long-linear-array detector and high-precision scanning mirror to achieve high-resolution and wide-swath thermal infrared data. The method has been implemented in the SDGs satellite and has shown promising test results.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Dandan Wang, Leiqiu Hu, James A. Voogt, Yunhao Chen, Ji Zhou, Gaijing Chang, Jinling Quan, Wenfeng Zhan, Zhizhong Kang
Summary: This study evaluates different schemes for determining model coefficients to quantify and correct the anisotropic impact from remote sensing LST for urban applications. The schemes have consistent results and accurately estimate parameter values, facilitating the broadening of parametric models.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Jamie Tolan, Hung - Yang, Benjamin Nosarzewski, Guillaume Couairon, Huy V. Vo, John Brandt, Justine Spore, Sayantan Majumdar, Daniel Haziza, Janaki Vamaraju, Theo Moutakanni, Piotr Bojanowski, Tracy Johns, Brian White, Tobias Tiecke, Camille Couprie
Summary: Vegetation structure mapping is crucial for understanding the global carbon cycle and monitoring nature-based approaches to climate adaptation and mitigation. This study presents the first high-resolution canopy height maps for California and Sao Paulo, achieved through the use of very high resolution satellite imagery and aerial lidar data. The maps provide valuable tools for forest structure assessment and land use monitoring.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Regina Eckert, Steffen Mauceri, David R. Thompson, Jay E. Fahlen, Philip G. Brodrick
Summary: In this paper, a mathematical framework is proposed to improve the retrieval of surface reflectance and atmospheric parameters by leveraging the expected spatial smoothness of the atmosphere. Experimental results show that this framework can reduce the surface reflectance retrieval error and surface-related biases.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Chongya Jiang, Kaiyu Guan, Yizhi Huang, Maxwell Jong
Summary: This study presents the Field Rover method, which uses vehicle-mounted cameras to collect ground truth data on crop harvesting status. The machine learning approach and remote sensing technology are employed to upscale the results to a regional scale. The accuracy of the remote sensing method in predicting crop harvesting dates is validated through comparison with satellite data.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Oksana V. Lunina, Anton A. Gladkov, Alexey V. Bochalgin
Summary: In this study, an unmanned aerial vehicle (UAV) was used to detect and map surface discontinuities with displacements of a few centimeters, indicating the presence of initial geological deformations. The study found that sediments of alluvial fans are susceptible to various tectonic and exogenous deformational processes, and the interpretation of ultra-high resolution UAV images can help recognize low-amplitude brittle deformations at an early stage. UAV surveys are critical for discerning neotectonic activity and its related hazards over short observation periods.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Feng Zhao, Weiwei Ma, Jun Zhao, Yiqing Guo, Mateen Tariq, Juan Li
Summary: This study presents a data-driven approach to reconstruct the terrestrial SIF spectrum using measurements from the TROPOMI instrument on Sentinel-5 precursor mission. The reconstructed SIF spectrum shows improved spatiotemporal distributions and demonstrates consistency with other datasets, indicating its potential for better understanding of the ecosystem function.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Stephen Stehman, John E. Wagner
Summary: This article investigates optimal sample allocation in stratified random sampling for estimation of accuracy and proportion of area in applications where the target class is rare. The study finds that precision of estimated accuracy has a stronger impact on sample allocation than estimation of proportion of area, and the trade-offs among these estimates become more pronounced as the target class becomes rarer. The results provide quantitative evidence to guide sample allocation decisions in specific applications.
REMOTE SENSING OF ENVIRONMENT
(2024)
Article
Environmental Sciences
Jingyao Zheng, Tianjie Zhao, Haishen Lu, Defu Zou, Nemesio Rodriguez-Fernandez, Arnaud Mialon, Philippe Richaume, Jianshe Xiao, Jun Ma, Lei Fan, Peilin Song, Yonghua Zhu, Rui Li, Panpan Yao, Qingqing Yang, Shaojie Du, Zhen Wang, Zhiqing Peng, Yuyang Xiong, Zanpin Xing, Lin Zhao, Yann Kerr, Jiancheng Shi
Summary: Soil moisture and freeze/thaw (F/T) play a crucial role in water and heat exchanges at the land-atmosphere interface. This study reports the establishment of a wireless sensor network for soil moisture and temperature over the permafrost region of Tibetan Plateau. Satellite-based surface soil moisture (SSM) and F/T products were evaluated using ground-based measurements. The results show the reliability of L-band passive microwave SSM and F/T products, while existing F/T products display earlier freezing and later thawing, leading to unsatisfactory accuracy.
REMOTE SENSING OF ENVIRONMENT
(2024)