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Sparse concentric ring arrays composed of aperiodic rings with elements equally spaced in each ring are capable of achieving circularly symmetric patterns with low sidelobe level (SLL) compared with the thinning concentric ring arrays. Here teaching learning based optimization (TLBO) algorithm which is based on stochastic optimization is first applied to synthesizing sparse concentric ring arrays...
The estimated radial velocity of moving target can be ambiguous in traditional two-channel synthetic aperture radar (SAR) system using along-track-interferometry (ATI) method. To mitigate radial velocity ambiguity of the moving target, we first establish the model of a two-channel SAR system and analyzed the basic principle of the dual-subband ATI (DS_ATI) approach. Then, we apply the model and the...
Water erosion is one of the major factors for performance degradation of cement asphalt mortar (CAM). In the paper, the strength variations of CAM exposed to water was investigated at various water temperatures (20°C, 40°C and 60°C) and pressures (0.0MPa, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa and 0.5MPa) and the microstructure evolution was analyzed by mercury intrusion porosimetry (MIP) and scan electronic...
The 3D imaging microwave altimeter is a proposed instrument for obtaining centimeter level accuracy of topography for ocean and meter-level accuracy of topography for land. In order to ensure the normal operation of the system and improve its performance, the EMI and EMC problems should be considered in design phase. In this paper, the architecture of altimeter system is shown and the main EMI sources...
Through introducing the entropy theory of thermodynamics, knowledge entropy is proposed, and the mathematic model of it is constructed to calculate uncertainty in organization knowledge content. The mechanism of knowledge transfer is analyzed, the mathematic model of knowledge transfer entropy is constructed which is used to evaluate the credible degree that organization knowledge acquires results...
As a production factor knowledge is becoming more and more important in today economy society, and knowledge has become the key for industry and the whole economy in the future. Each knowledge form about flowing, transfer and evolution, including knowledge flowing direction, has become hot and difficult problem in the manage science area. Based on studying about knowledge transfer, this paper discusses...
Ground moving target indication (GMTI) using spaceborne sparse array radar is attractive. To mitigate angle and Doppler ambiguities of the moving target detection for sparse array, the paper presented the model of a multi-carrier-frequency radar system and analyzed the basic principle of space time adaptive processing (STAP). Finally, the paper presented preliminary simulations to show that the angle...
In distributed satellites interferometric SAR (InSAR) system, short baselines usually make higher height ambiguity but the interferometric phase can be unwrapped much more easily, while the long baselines usually cause more complicated phase unwrapping problems but have less height ambiguity. It's of obvious significance if we can combine the data from baselines of different length. In this paper,...
In 3-D ISAR imaging, the separation of scatterers which have same Range-Doppler location is a key problem. In this paper, we propose to use a MIMO radar array, which is located in the z-axis direction, to measure the positions of scatterers of a synthesis scatterer. The x- and y-coordinates of scatters are obtained from ISAR image directly. The z-coordinates are reconstructed by the spatial frequencies...
Radar echo signal simulator is usually implemented based on a special kind of radar system, which makes radar simulation system single and be empty of flexibility. In terms of the above situation, a new kind of echo simulator has been prompted in this paper. Compared with traditional instruments, it is scalable, programmable and suitable for upgrade. It has been successfully used in the design of...
Compressive sensing technique has been shown capable of reducing the number of data samples beyond the Nyquist theorem, and achieving perfect reconstruction of the original signal. Because of its compressed sampling ability, compressive sensing has been found many applications in imaging, remote sensing conversion and many other fields. Although several kinds of radar imaging arithmetic were proposed,...
Radar altimeter echo simulation on ocean surface based upon Physical Optics (PO) method is implemented in this paper. PO method is a successful technique in the electromagnetic computation for targets whose dimensions are large compared with the wavelength of the incident wave. Using this method, we build the models to simulate the electromagnetic interaction occurring in ocean surface with an adaptive...
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