Geosynchronous synthetic aperture radar (GEO SAR) has great potentials in synthetic aperture radar ground moving target indication (SAR-GMTI) due to its high time resolution and wide swath coverage. But the signal-to-...
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Geosynchronous synthetic aperture radar (GEO SAR) has great potentials in synthetic aperture radar ground moving target indication (SAR-GMTI) due to its high time resolution and wide swath coverage. But the signal-to-noise ratio (SNR) of echo is too low and multichannel configuration cannot be realize in GEO monostatic SAR. Therefore, geosynchronous spaceborne-airborne bistatic multichannel synthetic aperture radar (GEO-SABM SAR) can realize enhanced SNR and multichannel configuration. In this paper, we establish the slant range model for GEO-SABM SAR and give the VSAR processing flowchart. Finally, the numerical experiments is given to verify the effectiveness of proposed method.
Geosynchronous Spaceborne-Airborne Bistatic multichannel SAR (GEO-SABM SAR) maintains the fine temporal sampling and wide coverage characteristics of monostatic GEO SAR. But due to the PRF of GEO platform is very low,...
ISBN:
(数字)9781728123455
ISBN:
(纸本)9781728123462
Geosynchronous Spaceborne-Airborne Bistatic multichannel SAR (GEO-SABM SAR) maintains the fine temporal sampling and wide coverage characteristics of monostatic GEO SAR. But due to the PRF of GEO platform is very low, azimuth spectrum aliasing (ASA) will occur in GEO-SABM SAR which will make a moving target divided into several sub-targets. In this paper, a location method for ground moving target with ASA has given. From the simulation results, the moving target can be discriminated and located.
Sentence semantic matching requires understanding the semantic relationship between two sentences, which is widely used in various natural language tasks such as paraphrase identification, natural language inference a...
Sentence semantic matching requires understanding the semantic relationship between two sentences, which is widely used in various natural language tasks such as paraphrase identification, natural language inference and question answering. Usually, the underlying structure of sentence is not strictly sequential, this structure is hierarchical. This paper studies how to better model the hierarchical structure of sentence for semantic matching. Recent research suggests that BERT implicitly captures classical, tree-like structures. Based on this, this paper proposes to further enhance the strength of modeling hierarchical structure of language with an advanced variant of LSTM – Ordered Neurons LSTM(ON-LSTM), which introduces a syntax-oriented inductive bias to perform the composition of classical tree structure. Experimental results demonstrate that the proposed approach, which enhances hierarchical structure of language, significantly improves the performance of sentence semantic matching.
With the development and growing applications of information technology, the coupling and dependency of space information network are becoming more and more intense. In this paper, the vulnerability of space informati...
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In view of the actual decentralized development of the satellite service constellation and the trend of space-ground integrated information network, based on the idea of clustering, methodology of complex network comm...
In view of the actual decentralized development of the satellite service constellation and the trend of space-ground integrated information network, based on the idea of clustering, methodology of complex network community structure, a business scenario-oriented satellite network structure is designed. On the one hand, it reflects the different separation and integration of satellite constellations in business scenarios. On the other hand, the 'head node' mechanism is introduced to be responsible for the interaction between constellation in different business scenarios. The satellite network structure is modeled using the growth and priority connection mechanism, and through computational derivation and simulation validation, the scale-free characteristics of the satellite network are revealed. Finally, through the simulation experiments on different satellite network parameters, the effect of different parameters on the static geometry, network efficiency, etc., are obtained. The influence of the law of the network will provide theoretical and methodological reference for the design of satellite network structure.
Main lobe interferences usually cause the distortion and peak offset of main lobe and the heighten of side lobe level in adaptive beamformers. The block matrix algorithm utilized the direction vector which was determi...
Main lobe interferences usually cause the distortion and peak offset of main lobe and the heighten of side lobe level in adaptive beamformers. The block matrix algorithm utilized the direction vector which was determined by both the antenna arrays and the direction of interference to eliminate the main lobe interference. But this algorithms is sensitive to the error occurred in the interference arrive angle and would consume the array of degrees of freedom. In this paper a new algorithm is proposed which projects the receive signal into a space which is orthogonal to the signal subspace to achieve the goal. The space can get by three steps. Frist we obtain eigenvalues by the decomposition of the covariance matrix of the snapshots to evaluate the noise power. Then we get a new matrix by removing the noise from the covariance matrix of the snapshots. At last we get the target space by conducting the singular value decomposition to the new matrix. Performance is mainly assessed in terms of the beamforming gain and the signal to interference and noise (SINR) ratio. The computer simulation shows the effective of this method.
The hyperspectral image(HSI) generated by most imaging spectrometer systems is constantly disturbed by noise. In this research, we introduced an HSI denoising method based on the theory of sparse coding extended to th...
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With rapid development of machine learning, supervised learning and reinforcement learning have witnessed a considerable success. However, some problems like the absence of supervising signal in supervised learning ar...
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In order to effectively combine the spectral information of the multispectral (MS) image with the spatial details of the panchromatic (PAN) image and improve the fusion quality, a fusion method based on morphological ...
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