| 1. |
- Aldenhoff, Wiebke, 1985, et al.
(författare)
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COMPARISON OF SENTINEL-1 SAR AND SENTINEL-3 ALTIMETRY DATA FOR SEA ICE TYPE DISCRIMINATION
- 2019
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Ingår i: IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium. - 9781538691540
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper near co-incidental Sentinel-1 C-band SAR imagery and Sentinel-3 SRAL Ku-band altimeter data are compared for their capabilities of sea ice type discrimination. Knowledge of sea ice type is important for climate research and safety in Arctic offshore operations. First-year ice is characterised by a low SAR backscatter intensity in both HH and HV polarisation compared to multi-year ice, while the altimeter waveform parameters show high pulse peakiness and peak power compared to multi-year ice. Thus SAR imagery and altimetry can principally discriminate different ice types. The complexity of the backscattered radar signal however impedes a clear separation of the two types for all cases. Cross comparison of the two sensors offers an opportunity of high resolution validation data, which is often lacking for sea ice studies.
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| 2. |
- Banda, Francesco, et al.
(författare)
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BIOMASS L2 Prototype Processor : Current Status
- 2019
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Ingår i: International Geoscience and Remote Sensing Symposium (IGARSS). - 9781538691540 ; , s. 5996-5999
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Konferensbidrag (refereegranskat)abstract
- The ESA BIOMASS mission will be the 7th Earth Explorer measuring the above-ground biomass (AGB) in the world's forests. The current ESA Level-2 (L2) implementation study focuses on defining and implementing the main algorithms for forest parameter retrieval from BIOMASS data. After the first year of L2 study innovative results were achieved: the development of ground cancellation, in particular, has proved to be huge value, since it removes from the data the effects of environmental variability and contributions unrelated to the forest carried in the ground scattering. In this paper the current processor implementation and validation activities of the L2 team will be described.
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| 3. |
- Elyouncha, Anis, 1978, et al.
(författare)
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Using Sentinel-1 Ocean Data for Mapping Sea Surface Currents Along the Southern Norwegian Coast
- 2019
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Ingår i: International Geoscience and Remote Sensing Symposium (IGARSS). - 9781538691540 ; , s. 8058-8061
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Konferensbidrag (refereegranskat)abstract
- In this paper, the capability of Sentinel-1 data to map ocean surface currents in the Skagerrak Sea, with a focus on the Norwegian Coastal Current (NCC), is investigated. Post-processing methods for removing artefacts in the data and improving of the geophysical interpretation are suggested. Scalloping is one major artefact, which significantly degrades the quality of the velocity maps. Two methods, in spatial and spectral domain, for correcting this effect are proposed. It is also found that the radial velocity provided in the Sentinel-1 ocean data is biased, hence land is used as a reference to correct for the absolute and inter-beam bias. Finally, the retrieved (corrected) velocity is compared to a regional ocean circulation model (ROMS). It is shown that there is a good agreement between the ocean model and the retrieved velocity with values of ≈ 0.8 m/s in the core of the NCC.
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| 4. |
- Haglund, Anders, et al.
(författare)
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Simulation of Effect of Periodically Missing Samples on Decoding in Passive Synthetic Aperture Radar System Using OFDM
- 2019
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Ingår i: International Geoscience and Remote Sensing Symposium (IGARSS). - 9781538691540 ; , s. 2949-2952
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Konferensbidrag (refereegranskat)abstract
- Passive synthetic aperture radar using transmitters of opportunity can be used for remote sensing, using frequency bands that are not normally allowed for transmitting radars. Passive radars do not transmit but instead use signals from other transmitting sources. Useful signal modulations for passive radar include OFDM (Orthogonal Frequency Division Multiplexing) signals for digital TV following the standard Digital Video Broadcasting Terrestrial (DVB-T) [1]. In this paper, we simulate the performance with an open software to decode the OFDM signal registered with the airborne synthetic aperture radar LORA. The LORA system does not register measured samples continuously but some percentage of consecutive samples are thrown away periodically. Moreover, the sampling rate of the LORA system gives a non-integer rational number of samples during the OFDM symbol time period. We conclude that the missing data samples can become deleterious for decoding the DVB-T signal and give guidelines to the maximum allowable data gaps.
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| 5. |
- Miura, Y., et al.
(författare)
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SOIL MOISTURE MONITORING OF AGRICULTURAL FIELDS IN BURKINA FASO USING DUAL POLARIZED SENTINEL-1A DATA
- 2019
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Ingår i: International Geoscience and Remote Sensing Symposium (IGARSS). - : IEEE. - 9781538691540 ; , s. 7045-7048
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Konferensbidrag (refereegranskat)abstract
- We investigated the correlation between backscatter and soil moisture considering precipitation and crop effects using dual polarized Sentinel-1A data. The analyzed data consist of a time-series of 38 Sentinel-1A GRD images acquired on a 12-days repeat cycle from July 2017 to October 2018 over Sapone in Burkina Faso. We show that the temporal change of backscatter corresponds to the soil moisture content rather than crops.
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| 6. |
- Molin, Ricardo D., Jr., et al.
(författare)
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A CHANGE DETECTION ALGORITHM FOR SAR IMAGES BASED ON LOGISTIC REGRESSION
- 2019
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Ingår i: 2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019). - : IEEE. - 9781538691540 ; , s. 1514-1517
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Konferensbidrag (refereegranskat)abstract
- This paper presents an incoherent change detection algorithm (CDA) for synthetic aperture radar (SAR) images based on logistic regression. The input data consists of a set of 24 SAR images acquired in a test site in northern Sweden [1]. Subsets of these images are trained based on pixel amplitude, flight heading and neighboring features such as local mean, standard deviation and skewness. The proposed method intends to explore the advantadges from both pixel- and object-based approaches, while evaluating multiple features in amplitude only SAR images. Preliminary results based on K-fold cross validation have shown that the proposed CDA achieves good performance when compared to the results presented in [1].
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| 7. |
- Vu, Viet Thuy, et al.
(författare)
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A MEASUREMENT CAMPAIGN IN HARBOR TO DETECT CHANGES OF ACTIVITIES
- 2019
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Ingår i: 2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019). - : IEEE. - 9781538691540 ; , s. 1494-1497
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Konferensbidrag (refereegranskat)abstract
- The typical activities in a harbor mainly concern logistics, traffic and transportation that need to be monitored or optimized. This paper reports a measurement campaign whose goal is to evaluate the performance of activity surveillance in a harbor using satellite SAR systems. The measurements were conducted in the southern Baltic sea, around the Verko harbor in Karlskrona, Sweden in the middle of 2018. The SAR data acquisition was with TerraSAR-X/TanDEM-X operating in staring spotlight mode as high resolution was desired. For an accurate evaluation, all activities in the Verko harbor were video recorded by a drone during the satellite measurement time. Some radar corner reflectors were also deployed on the ground that are available for co-registration. The data associated with two measurements in the end of August and in the beginning of September is presented in this paper. The SAR change detection processing and the initial analysis show the possibility to monitor activities concerning logistics, traffic and transportation using satellite SAR.
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| 8. |
- Vu, Viet Thuy, et al.
(författare)
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Stability in Sar Change Detection Results Using Bivariate Rayleigh Distribution for Statistical Hypothesis Test
- 2019
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Ingår i: International Geoscience and Remote Sensing Symposium (IGARSS). - : Institute of Electrical and Electronics Engineers Inc.. - 9781538691540 ; , s. 37-40
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Konferensbidrag (refereegranskat)abstract
- A statistical hypothesis test for wavelength-resolution SAR change detection can be derived with the bivariate distributions such as Rayleigh, Gamma and K. The paper investigates the stability of change detection results obtained with a statistical hypothesis test using bivariate Rayleigh distribution. Some practical issues concerning the implementation of the statistical hypothesis test such as scale parameter estimation, target magnitude assumptions and Bessel function calculation are also addressed. The statistical hypothesis test using bi-variate Rayleigh distribution are experimented with the data set containing 24 CARABAS II images. It is shown that beside the simplicity and efficiency, a statistical hypothesis test using bivariate Rayleigh distribution can provide very stable change detection results. © 2019 IEEE.
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| 9. |
- Zhang, Tao, et al.
(författare)
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Ship detection using the surface scattering similarity and scattering power
- 2019
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Ingår i: 2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019). - : IEEE. - 9781538691540 ; , s. 1264-1267
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Konferensbidrag (refereegranskat)abstract
- Sea surface and ship have different backscattering mechanisms, in which surface scattering is predominant for sea surface in the low sea state case. Based on this fact, many ship detectors have been developed by suppressing the surface scattering resulted from sea surface. Actually, small ship may also have strong surface scattering sometimes. In such a case, the methods of avoiding using surface scattering features may easily miss the detection of small ships. To verify this point, in this paper, we first analyze the shortcomings of An's method which is based on surface scattering similarity and the power maximization synthesis detector (PMS), and then improve it for detecting small ships more effectively. In order to demonstrate the performance of the proposed method, AIRSAR L-Band Polarimetric SAR dataset is exploited. Comparing to other methods, the new method shows a better ship detection performance.
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| 10. |
- Zhang, Yongchao, et al.
(författare)
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Online High Resolution Stochastic Radiation Radar Imaging using Sparse Covariance Fitting
- 2019
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Ingår i: IGARSS 2019 : 2019 IEEE International Geoscience and Remote Sensing Symposium - 2019 IEEE International Geoscience and Remote Sensing Symposium. - 9781538691557 - 9781538691540 ; , s. 8562-8565
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Konferensbidrag (refereegranskat)abstract
- Stochastic radiation radar (SRR) systems allow for the forming of radar images by transmitting stochastic signals to form the stochastic radiation field and thereby increase the target observation information to achieve high resolution imaging. In this paper, we examine the use of the online SParse Iterative Covariance-based Estimation (SPICE) algorithm to suppress the noise and improve the operational efficiency. The SPICE algorithm is based on a weighted covariance fitting criterion, and has recently been generalized to allow for an improved reconstruction performance. The used online extension can take advantage of echoes non-correlation along time, allowing for updating the imaging result through successive echo sequences. The simulation results verify the superior performance of the resulting estimator as compared to other recent SRR imaging methods.
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