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Publications of year 2021

Articles in journal or book chapters

  1. E. Casalini, J. Fagir, and D. Henke. Moving Target Refocusing With the FMCW SAR System MIRANDA-35. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 14:1283-1291, 2021. Keyword(s): SAR Processing, Moving Target, Airborne SAR, Synthetic aperture radar, Radar imaging, Earth, Signal processing algorithms, Remote sensing, Radar polarimetry, Motion compensation, Frequency-modulated continuous-wave (FMCW), inverse synthetic aperture radar (ISAR), MIRANDA-35, motion compensation (MoComp), radar imaging, synthetic aperture radar (SAR).
    Abstract: Inverse synthetic aperture radar is a commonly adopted technique for producing high-resolution images of moving targets. This article investigates the imaging capabilities of high-frequency and high-bandwidth systems by means of two distinct experiments. The deployed sensor is the Fraunhofer FHR MIRANDA-35, a millimeter-wave synthetic aperture radar airborne system, which transmits frequency-modulated continuous-wave signals at the Ka-band and is capable of achieving centimeter resolution. The performances are assessed by comparing the derived estimates (e.g., radial velocity and acceleration, and dimensions) with independent ground measurements. The resulting accuracy can be summarized as follows: the mean value of the percent error is 2.05% and 2.11% for radial velocity and acceleration, respectively, and 4.27% for the target dimensions.

    @Article{casaliniFagirHenke2021MovingTargetRefocusingFMCWSARSystemMIRANDA35,
    author = {E. {Casalini} and J. {Fagir} and D. {Henke}},
    journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
    title = {Moving Target Refocusing With the FMCW SAR System MIRANDA-35},
    year = {2021},
    issn = {2151-1535},
    pages = {1283-1291},
    volume = {14},
    abstract = {Inverse synthetic aperture radar is a commonly adopted technique for producing high-resolution images of moving targets. This article investigates the imaging capabilities of high-frequency and high-bandwidth systems by means of two distinct experiments. The deployed sensor is the Fraunhofer FHR MIRANDA-35, a millimeter-wave synthetic aperture radar airborne system, which transmits frequency-modulated continuous-wave signals at the Ka-band and is capable of achieving centimeter resolution. The performances are assessed by comparing the derived estimates (e.g., radial velocity and acceleration, and dimensions) with independent ground measurements. The resulting accuracy can be summarized as follows: the mean value of the percent error is 2.05% and 2.11% for radial velocity and acceleration, respectively, and 4.27% for the target dimensions.},
    doi = {10.1109/JSTARS.2020.3042601},
    file = {:casaliniFagirHenke2021MovingTargetRefocusingFMCWSARSystemMIRANDA35.pdf:PDF},
    keywords = {SAR Processing, Moving Target, Airborne SAR,Synthetic aperture radar;Radar imaging;Earth;Signal processing algorithms;Remote sensing;Radar polarimetry;Motion compensation;Frequency-modulated continuous-wave (FMCW);inverse synthetic aperture radar (ISAR);MIRANDA-35;motion compensation (MoComp);radar imaging;synthetic aperture radar (SAR)},
    owner = {ofrey},
    
    }
    


  2. Dyre Oliver Dammann, Mark A. Johnson, Emily R. Fedders, Andrew R. Mahoney, Charles L. Werner, Christopher M. Polashenski, Franz J. Meyer, and Jennifer K. Hutchings. Ground-Based Radar Interferometry of Sea Ice. Remote Sensing, 13(1), 2021.
    Abstract: In light of recent Arctic change, there is a need to better understand sea ice dynamic processes at the floe scale to evaluate sea ice stability, deformation, and fracturing. This work investigates the use of the Gamma portable radar interferometer (GPRI) to characterize sea ice displacement and surface topography. We find that the GPRI is best suited to derive lateral surface deformation due to mm-scale horizontal accuracy. We model interferometric phase signatures from sea ice displacement and evaluate possible errors related to noise and antenna motion. We compare the analysis with observations acquired during a drifting ice camp in the Beaufort Sea. We used repeat-scan and stare-mode interferometry to identify two-dimensional shear and to track continuous uni-directional convergence. This paper demonstrates the capacity of the GPRI to derive surface strain on the order of 10−7 and identify different dynamic regions based on sub-mm changes in displacement. The GPRI is thus a promising tool for sea ice applications due to its high accuracy that can potentially resolve pre- and post-fracture deformation relevant to sea ice stability and modeling.

    @Article{dammannJohnsonFeddersMahoneyWernerPolashenskiMeyerHutchingsREMOTESENSING2021GroundBasedRadarInterferometryOfSeaIce,
    author = {Dammann, Dyre Oliver and Johnson, Mark A. and Fedders, Emily R. and Mahoney, Andrew R. and Werner, Charles L. and Polashenski, Christopher M. and Meyer, Franz J. and Hutchings, Jennifer K.},
    journal = {Remote Sensing},
    title = {Ground-Based Radar Interferometry of Sea Ice},
    year = {2021},
    issn = {2072-4292},
    number = {1},
    volume = {13},
    abstract = {In light of recent Arctic change, there is a need to better understand sea ice dynamic processes at the floe scale to evaluate sea ice stability, deformation, and fracturing. This work investigates the use of the Gamma portable radar interferometer (GPRI) to characterize sea ice displacement and surface topography. We find that the GPRI is best suited to derive lateral surface deformation due to mm-scale horizontal accuracy. We model interferometric phase signatures from sea ice displacement and evaluate possible errors related to noise and antenna motion. We compare the analysis with observations acquired during a drifting ice camp in the Beaufort Sea. We used repeat-scan and stare-mode interferometry to identify two-dimensional shear and to track continuous uni-directional convergence. This paper demonstrates the capacity of the GPRI to derive surface strain on the order of 10−7 and identify different dynamic regions based on sub-mm changes in displacement. The GPRI is thus a promising tool for sea ice applications due to its high accuracy that can potentially resolve pre- and post-fracture deformation relevant to sea ice stability and modeling.},
    article-number = {43},
    doi = {10.3390/rs13010043},
    file = {:dammannJohnsonFeddersMahoneyWernerPolashenskiMeyerHutchingsREMOTESENSING2021GroundBasedRadarInterferometryOfSeaIce.pdf:PDF},
    owner = {ofrey},
    url = {https://www.mdpi.com/2072-4292/13/1/43},
    
    }
    


  3. D. Feng, D. An, L. Chen, and X. Huang. Holographic SAR Tomography 3-D Reconstruction Based on Iterative Adaptive Approach and Generalized Likelihood Ratio Test. IEEE Transactions on Geoscience and Remote Sensing, 59(1):305-315, Jan. 2021. Keyword(s): Image resolution, Apertures, Image reconstruction, Signal resolution, Synthetic aperture radar, Tomography, Three-dimensional displays, 3-D imaging, generalized likelihood ratio test (GLRT), holographic synthetic aperture radar (HoloSAR) tomography, iterative adaptive approach (IAA).
    Abstract: Holographic synthetic aperture radar (HoloSAR) tomography is an attractive imaging mode that can retrieve the 3-D scattering information of the observed scene over 360 azimuth angle variation. To improve the resolution and reduce the sidelobes in elevation, the HoloSAR imaging mode requires many passes in elevation, thus decreasing its feasibility. In this article, an imaging method based on iterative adaptive approach (IAA) and generalized likelihood ratio test (GLRT) is proposed for the HoloSAR with limited elevation passes to achieve super-resolution reconstruction in elevation. For the elevation reconstruction in each range-azimuth cell, the proposed method first adopts the nonparametric IAA to retrieve the elevation profile with improved resolution and suppressed sidelobes. Then, to obtain sparse elevation estimates, the GLRT is used as a model order selection tool to automatically recognize the most likely number of scatterers and obtain the reflectivities of the detected scatterers inside one range-azimuth cell. The proposed method is a super-resolving method. It does not require averaging in range and azimuth, thus it can maintain the range-azimuth resolution. In addition, the proposed method is a user parameter-free method, so it does not need the fine-tuning of any hyperparameters. The super-resolution power and the estimation accuracy of the proposed method are evaluated using the simulated data, and the validity and feasibility of the proposed method are verified by the HoloSAR real data processing results.

    @Article{fengAnChenHuangTGRS2021HolographicSARTomography,
    author = {D. {Feng} and D. {An} and L. {Chen} and X. {Huang}},
    journal = {IEEE Transactions on Geoscience and Remote Sensing},
    title = {Holographic SAR Tomography 3-D Reconstruction Based on Iterative Adaptive Approach and Generalized Likelihood Ratio Test},
    year = {2021},
    issn = {1558-0644},
    month = {Jan.},
    number = {1},
    pages = {305-315},
    volume = {59},
    abstract = {Holographic synthetic aperture radar (HoloSAR) tomography is an attractive imaging mode that can retrieve the 3-D scattering information of the observed scene over 360 azimuth angle variation. To improve the resolution and reduce the sidelobes in elevation, the HoloSAR imaging mode requires many passes in elevation, thus decreasing its feasibility. In this article, an imaging method based on iterative adaptive approach (IAA) and generalized likelihood ratio test (GLRT) is proposed for the HoloSAR with limited elevation passes to achieve super-resolution reconstruction in elevation. For the elevation reconstruction in each range-azimuth cell, the proposed method first adopts the nonparametric IAA to retrieve the elevation profile with improved resolution and suppressed sidelobes. Then, to obtain sparse elevation estimates, the GLRT is used as a model order selection tool to automatically recognize the most likely number of scatterers and obtain the reflectivities of the detected scatterers inside one range-azimuth cell. The proposed method is a super-resolving method. It does not require averaging in range and azimuth, thus it can maintain the range-azimuth resolution. In addition, the proposed method is a user parameter-free method, so it does not need the fine-tuning of any hyperparameters. The super-resolution power and the estimation accuracy of the proposed method are evaluated using the simulated data, and the validity and feasibility of the proposed method are verified by the HoloSAR real data processing results.},
    doi = {10.1109/TGRS.2020.2994201},
    file = {:fengAnChenHuangTGRS2021HolographicSARTomography.pdf:PDF},
    keywords = {Image resolution;Apertures;Image reconstruction;Signal resolution;Synthetic aperture radar;Tomography;Three-dimensional displays;3-D imaging;generalized likelihood ratio test (GLRT);holographic synthetic aperture radar (HoloSAR) tomography;iterative adaptive approach (IAA)},
    owner = {ofrey},
    
    }
    


  4. D. -H. Jung, D. -H. Kim, M. T. Azim, J. Park, and S. -O. Park. A Novel Signal Processing Technique for Ku-Band Automobile FMCW Fully Polarimetric SAR System Using Triangular LFM. IEEE Transactions on Instrumentation and Measurement, 70:1-10, 2021. Keyword(s): SAR Processing, carborne SAR, Frequency modulation, Signal processing algorithms, Signal processing, Polarimetry, Automobiles, Doppler effect, Synthetic aperture radar, Automobile synthetic aperture radar (SAR), frequency modulated continuous wave (FMCW) radar, fully polarimetric SAR (PolSAR), linear frequency modulation (LFM), range Doppler algorithm (RDA), SAR, triangular waveform.
    Abstract: This article presents a novel signal technique for Ku-band automobile frequency-modulated continuous-wave fully polarimetric synthetic aperture radar (FMCW PolSAR) system using triangular linear frequency modulation (LFM). Our proposed system shows the first utilizations of triangular LFM for an FMCW PolSAR. The proposed signal processing algorithm is based on the range Doppler algorithm (RDA). We developed an FMCW PolSAR system that transmits triangular LFM signals, which are used less frequently than sawtooth LFM in an SAR sensor. Using a theoretical background, we describe its configuration and how it works. We propose the novel processing solution, which forms two kinds of single-polarization images from a raw data set and is suitable for our system. We obtained all four kinds of single-polarization images from two raw data sets while using the triangular LFM. In comparison, when using sawtooth LFM, we obtained the four images from four raw data sets by repeating the RDA four times. The proposed method simplifies the FMCW PolSAR system configuration and the processing algorithm. We collected FMCW PolSAR raw data from an experimentally equipped automobile while maintaining a constant speed on a highway. The proposed algorithm and system were validated by processing a high-resolution FMCW PolSAR image.

    @Article{jungKimAzimParkParkIEEETIM2021KuBandAutomobileFMCWFulPolSARSystem,
    author = {D. -H. {Jung} and D. -H. {Kim} and M. T. {Azim} and J. {Park} and S. -O. {Park}},
    journal = {IEEE Transactions on Instrumentation and Measurement},
    title = {A Novel Signal Processing Technique for {Ku}-Band Automobile {FMCW} Fully Polarimetric {SAR} System Using Triangular {LFM}},
    year = {2021},
    issn = {1557-9662},
    pages = {1-10},
    volume = {70},
    abstract = {This article presents a novel signal technique for Ku-band automobile frequency-modulated continuous-wave fully polarimetric synthetic aperture radar (FMCW PolSAR) system using triangular linear frequency modulation (LFM). Our proposed system shows the first utilizations of triangular LFM for an FMCW PolSAR. The proposed signal processing algorithm is based on the range Doppler algorithm (RDA). We developed an FMCW PolSAR system that transmits triangular LFM signals, which are used less frequently than sawtooth LFM in an SAR sensor. Using a theoretical background, we describe its configuration and how it works. We propose the novel processing solution, which forms two kinds of single-polarization images from a raw data set and is suitable for our system. We obtained all four kinds of single-polarization images from two raw data sets while using the triangular LFM. In comparison, when using sawtooth LFM, we obtained the four images from four raw data sets by repeating the RDA four times. The proposed method simplifies the FMCW PolSAR system configuration and the processing algorithm. We collected FMCW PolSAR raw data from an experimentally equipped automobile while maintaining a constant speed on a highway. The proposed algorithm and system were validated by processing a high-resolution FMCW PolSAR image.},
    doi = {10.1109/TIM.2020.3011601},
    file = {:jungKimAzimParkParkIEEETIM2021KuBandAutomobileFMCWFulPolSARSystem.pdf:PDF},
    keywords = {SAR Processing, carborne SAR,Frequency modulation;Signal processing algorithms;Signal processing;Polarimetry;Automobiles;Doppler effect;Synthetic aperture radar;Automobile synthetic aperture radar (SAR);frequency modulated continuous wave (FMCW) radar;fully polarimetric SAR (PolSAR);linear frequency modulation (LFM);range Doppler algorithm (RDA);SAR;triangular waveform},
    owner = {ofrey},
    
    }
    


  5. S. T. Peters, D. M. Schroeder, M. S. Haynes, D. Castelletti, and A. Romero-Wolf. Passive Synthetic Aperture Radar Imaging Using Radio-Astronomical Sources. IEEE Trans. Geosci. Remote Sens., pp 1-16, 2021. Keyword(s): Synthetic aperture radar, Passive radar, Sun, Radar, Focusing, Signal to noise ratio, Mathematical model, Passive radar, passive radio sounding, passive synthetic aperture radar (SAR), radio echo sounding, Back-Projection, Time-Domain Back-Projection, TDBP.
    Abstract: Recent work has demonstrated a passive radio sounding approach that uses the Sun as a source for echo detection and ranging. As the Sun is a moving source with a position that is known a priori, we evaluate this technique's capabilities to measure the echo's phase history, map topography, and perform synthetic aperture radar (SAR) focusing. Here, we present our approach to implementing passive SAR using a compact, temporally incoherent radio-astronomical source as a signal of opportunity. We first evaluate the passive system's capabilities to obtain an echo from a rough surface by determining the critical signal-to-noise ratio (SNR) for reliably observing the Sun's echo reflection with our passive instrument. We then demonstrate that our technique can detect the necessary changes in range, phase, and reflectivity of an echo from the Sun. We next present the experimental results of our passive radar testing using the Sun at Dante's View, Death Valley, to highlight this technique's ability to perform 2-D imaging. Finally, with synthetic data, we demonstrate that we can use time-domain backprojection to focus a planar white noise signal, perform passive SAR imaging, and improve the measurement's SNR and azimuth resolution. The results of passive SAR focusing on white noise highlight the potential for the Sun and Jupiter's radio emissions to perform surface and subsurface imaging for planetary and terrestrial observations.

    @Article{petersSchroederHaynesCastellettiRomeroWolfTGRS2021PassiveTDBPSARImagingUsingRadioAstronomicalSources,
    author = {S. T. {Peters} and D. M. {Schroeder} and M. S. {Haynes} and D. {Castelletti} and A. {Romero-Wolf}},
    journal = {IEEE Trans. Geosci. Remote Sens.},
    title = {Passive Synthetic Aperture Radar Imaging Using Radio-Astronomical Sources},
    year = {2021},
    issn = {1558-0644},
    pages = {1-16},
    abstract = {Recent work has demonstrated a passive radio sounding approach that uses the Sun as a source for echo detection and ranging. As the Sun is a moving source with a position that is known a priori, we evaluate this technique's capabilities to measure the echo's phase history, map topography, and perform synthetic aperture radar (SAR) focusing. Here, we present our approach to implementing passive SAR using a compact, temporally incoherent radio-astronomical source as a signal of opportunity. We first evaluate the passive system's capabilities to obtain an echo from a rough surface by determining the critical signal-to-noise ratio (SNR) for reliably observing the Sun's echo reflection with our passive instrument. We then demonstrate that our technique can detect the necessary changes in range, phase, and reflectivity of an echo from the Sun. We next present the experimental results of our passive radar testing using the Sun at Dante's View, Death Valley, to highlight this technique's ability to perform 2-D imaging. Finally, with synthetic data, we demonstrate that we can use time-domain backprojection to focus a planar white noise signal, perform passive SAR imaging, and improve the measurement's SNR and azimuth resolution. The results of passive SAR focusing on white noise highlight the potential for the Sun and Jupiter's radio emissions to perform surface and subsurface imaging for planetary and terrestrial observations.},
    doi = {10.1109/TGRS.2021.3050429},
    file = {:petersSchroederHaynesCastellettiRomeroWolfTGRS2021PassiveTDBPSARImagingUsingRadioAstronomicalSources.pdf:PDF},
    keywords = {Synthetic aperture radar;Passive radar;Sun;Radar;Focusing;Signal to noise ratio;Mathematical model;Passive radar;passive radio sounding;passive synthetic aperture radar (SAR);radio echo sounding, Back-Projection, Time-Domain Back-Projection, TDBP},
    owner = {ofrey},
    
    }
    


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This collection of SAR literature is far from being complete.
It is rather a collection of papers which I store in my literature data base. Hence, the list of publications under PUBLICATIONS OF AUTHOR'S NAME should NOT be mistaken for a complete bibliography of that author.




Last modified: Mon Feb 1 16:39:00 2021
Author: Othmar Frey, Earth Observation and Remote Sensing, Institute of Environmental Engineering, Swiss Federal Institute of Technology - ETH Zurich .


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