- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Estimation and Removal of Strong Range Ambiguities in Multistatic Synthetic Aperture Radar With Multiple Elevation Beams
摘要： Bistatic and multistatic synthetic aperture radar (SAR) can greatly improve system performance in various aspects, especially in achieving high-resolution wide-swath (HRWS) images. However, the specific system structure may lead to a higher degree of range ambiguities. This letter studies the structure of multistatic multiple elevation beams (MMEB) system which achieves HRWS images with the drawback of more serious range ambiguities compared with the conventional SAR which must be suppressed to get an acceptable system performance. The character that the receivers form, a prospective distributed multichannel system in azimuth, can give a guide in estimating the strong range ambiguities and remove them. An innovative method in estimating and removing (not just smearing) the strong range ambiguities based on this character is proposed. Theoretical analysis and experimental results show the effectiveness of the method. The proposed method considerably improves the range ambiguous performance of the MMEB system without using digital beamforming or pulse coding and makes full use of the system character, and thus improves the applicability of the system.
关键词： multistatic multiple elevation beams (MMEB),high-resolution wide-swath (HRWS),range ambiguities,Bistatic and multistatic,synthetic aperture radar (SAR)
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Incorporating Incidence Angle Variation into Sar Image Segmentation
摘要： We present a new approach for incorporating incidence angle derived synthetic aperture radar (SAR) brightness variation directly into SAR image analysis. This approach is unique in that the incidence angle dependency is modeled explicitly into the probability density function rather than an image-wide pre-processing ‘correction’. It can then be used for supervised and unsupervised image analysis, and is notably able to account for a different dependency rate for each class. This has potential benefits for wide-swath SAR imagery over flat areas and ocean, wide angled airborne and UAV based SAR data, connecting narrow-beam SAR images at different acquisition angles, as well as land-based analysis with local topographic terrain angles. An initial example demonstrates unsupervised image segmentation applied to sea ice mapping for meteorological services and climate science, and is compared to the same algorithm without the incidence angle modeling.
关键词： Terrain Correction,Sentinel-1,Wide-swath imagery,Synthetic Aperture Radar,Incidence Angle Correction
更新于2025-09-23 15:21:21
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A High-Resolution 220-GHz Ultra-Wideband Fully Integrated ISAR Imaging System
摘要： In this paper, an ultra-wideband fully integrated imaging radar at sub-terahertz (sub-THz) frequencies is presented, which demonstrates a fine lateral resolution without using any focal lens/mirror. We have achieved a lateral resolution of 2 mm for an object at 23-cm distance as well as a range resolution of 2.7 mm. To achieve the decent range resolution, in a frequency modulation continuous wave radar configuration, a state-of-the-art chirp bandwidth (BW) of 62.4 GHz at a center frequency of 221.1 GHz is generated and efficiently radiated. We have presented a design technique for the optimal design of the passive embedding around the core transistor to maximize the tuning BW of the voltage controlled oscillator. At the receiver side, to maximize the intermediate frequency level, a subharmonic mixer is utilized, which is designed for the lowest conversion loss. Finally, to obtain the fine lateral resolution, we have implemented near-field beamforming algorithm based on the inverse synthetic aperture radar (ISAR) systems. The synthesized beamwidth is less than 0.5°; hence, high-resolution images are reconstructed. The system is fabricated in a 55-nm BiCMOS process. To the best of our knowledge, this is the first imaging radar at THz/sub-THz frequencies, which utilizes ISAR to achieve a high lateral resolution while the radar system is fully integrated.
关键词： ultra-wideband,Frequency modulation continuous wave (FMCW),remote sensing,THz,radar,sub-terahertz (sub-THz),oscillator,inverse synthetic aperture radar (ISAR),plane wave
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Ship Detection Based on Deep Convolutional Neural Networks for Polsar Images
摘要： In this paper, we proposed a ship detection method based on deep convolutional neural networks for PolSAR images. The proposed ship detector firstly segments PolSAR images into sub-samples using a sliding window of fixed size to effectively extract translational-invariant spatial features. Further, the modified faster region based convolutional neural network (Faster-RCNN) method is utilized to realize ship detection for ships with different sizes and fusion the detection result. Finally, the proposed method was validated using real measured NASA/JPL AIRSAR datasets by comparing the performance with the modified constant false alarm rate (CFAR) detector. The comparison results demonstrate the validity and generality of the proposed detection algorithm.
关键词： Deep convolutional neural networks,polarimetric synthetic aperture radar (PolSAR),ship detection
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Two-Dimensional Displacement Analysis with Sar Images Based on Persistent Scatterer Clustering
摘要： In this paper, we propose a two-dimensional displacement analysis method with persistent scatterer (PS) clustering technique for monitoring ground and buildings. PS interferometry (PSI) technique measures millimetric displacement of ground and buildings, by employing stable reflection points called PSs obtained by a time-series analysis of synthetic aperture radar images. In order to extend PSI technique to two-dimensional displacement analysis, alignment and integration analysis of PSs obtained by different observation directions are needed. The proposed method integrates the PSs aligned by PS clustering, which separates the PSs corresponding to the structures assuming that displacements of the PSs on a rigid structure are similar. The PS clustering leads to an easy alignment of the PSs before the integration of displacements from different observation directions. The resulting integrated displacement analysis avoids errors caused by inappropriate interpolation in the conventional alignment method. Experimental results demonstrate that the proposed method achieves accuracy comparable with benchmarks.
关键词： clustering,persistent scatterer interferometry,synthetic aperture radar,Displacement analysis
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Annular Array 3-D Sar: Resolution Analysis and Data Processing
摘要： Array synthetic aperture radar (SAR) is one of the hot areas in radar imaging field because of its three-dimensional (3-D) imaging ability. Combining the advantages of linear array SAR in aspect of side-lobe suppression and circular SAR in aspect of high resolution, a new kind of annular array synthetic aperture radar (AASAR) mode is employed for 3-D microwave imaging. Based on the mathematical derivation of AASAR model, the sparse layout of the annular array in the cross-track direction can acquire 3-D high resolution and effective side-lobe suppression ability. Then on this basis, a proto-type AASAR experiment system is built, and some 3-D AASAR imaging outdoor experiments are conducted. Through the experiment result, the validity of 3-D AASAR imaging can be demonstrated.
关键词： 3-D imaging,annular array,high resolution,side-lobe suppression,Synthetic aperture radar
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Pr-Based Sar Reconstruction Autofocus Algorithm for Persistent Surveillance Change Detection
摘要： Random phase noises arising from frequency jitter of transmit signal and atmospheric turbulence result in corrupted synthetic aperture radar (SAR) imagery, which in turn degrades change detection (CD) performance. In this paper, a phase retrieval (PR) based SAR reconstruction autofocus framework by exploiting the hidden convexity is proposed with the goal of achieving reliable persistent surveillance CD. Firstly the original non-convex quartic SAR reconstruction is reformulated as a convex quadratic program. Under the minimum phase assumption, the auto-correlation retrieval-Kolmogorov factorization (CoRK) algorithm is then utilized to optimally and efficiently retrieve the underlying SAR reflectivity. The devised scheme possesses effective capabilities of phase noise mitigation, thus has a superior CD performance. Experimental results are provided to verify the effectiveness of the proposed method.
关键词： Synthetic aperture radar (SAR),hidden convexity,change detection (CD),phase retrieval (PR),random phase noises
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - FAST DECEPTIVE JAMMING AGAINST TOPSAR
摘要： Terrain observation by progressive scans synthetic aperture radar (TOPSAR) is a novel two dimensional imaging mode with wide swath coverage. However, it will cause problems when our regions of interest are being detected by hostile TOPSAR. To prevent this threaten from TOPSAR, this paper presents a corresponding deceptive jamming method by taken the effect of changing relative position between jammer and TOPSAR platform into consideration. Meanwhile, our approach decomposes the jamming problem against TOPSAR into simpler sub-problems of the same type. Therefore, a parallel processing scheme could be carried out to implement effectively jamming against TOPSAR.
关键词： electronic countermeasure (ECM),deceptive jamming,Terrain observation by progressive scans synthetic aperture radar (TOPSAR),partitioned deceptive template
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - An Asymmetric Split-Spectrum Method for Estimating the Ionospheric Artifacts in Insar Data
摘要： The last two decades have witnessed a dramatic development of the satellite interferometric synthetic aperture radar (InSAR) technology in both the theoretical methods and operational platforms. The propagation errors of SAR signal in the ionosphere is one of the problematic issues for the low-frequency SAR systems, such as L-band and P-band, and can also seriously degrade the accuracy of InSAR. Recently, there has been renewed interest in the range split-spectrum method for the ionopheric correction after some critical issues are resolved. In this study, we used the ultra-fine observation mode (80 MHz) of the Advanced Land Observation Satellite-2 (ALOS-2) phased array-type L-band synthetic aperture radar-2 (PALSAR-2) data over the 2016 Kumamoto earthquake to evaluate the performance of an asymmetric split-spectrum method for the ionospheric correction. The presented works demonstrate the effectiveness of two types of the asymmetric split-spectrum method for mitigating the ionospheric artifact in InSAR, as compared with the conventional split-spectrum method. Additionally, this study provides practical insight into the ionospheric correction strategies of the scheduled NASA-ISRO synthetic aperture radar (NISAR) mission.
关键词： 2016 Kumamoto earthquake,ionospheric artifact correction,Interferometric synthetic aperture radar (InSAR),NISAR,ALOS-2 PALSAR-2
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - The 2-Looks Tops Mode: Enhanced Sensitivity To Ground Displacement In Azimuth Direction with Burst-Mode Sar Systems. Demonstration With Terrasar-X
摘要： The Terrain Observation by Progressive Scans (TOPS) SAR acquisition mode achieves wide coverage area by employing subapertures. This way multiple subswaths can be acquired. It overcomes the problems of scalloping and azimuth-varying ambiguities inherent to the ScanSAR mode by introducing a steering of the beam in the along-track direction. The draw-back is that, due to the burst operation mode, the azimuth resolution is strongly worsened with respect to the conventional StripMap mode. This reduces the performance on the retrieval of the ground displacement in the azimuth direction. In this contribution we provide an update on the last developments with our proposed 2-looks TOPS mode. This mode has been devised to mitigate the degraded sensitivity on the retrieval of ground deformation azimuth shifts of 1-look TOPS acquisitions. We will present the last improvements to the mode as well as updated results with time-series of experimental TerraSAR-X data.
关键词： 2-looks TOPS,SAR Interferometry,North-South deformation,TerraSAR-X,Synthetic Aperture Radar (SAR)
更新于2025-09-23 15:21:21