共查询到18条相似文献,搜索用时 93 毫秒
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《中国无线电电子学文摘》2002,(1)
rl、P72,TN015 02011691信道互祸和不平衡度对综合孔径微波辐射计复相关千涉测量的影响分析及其校准/董晓龙,吴季,姜景山(中国科学院空间科学与应用研究中,。)11电子学报4一2 001,29(7)一947一949文中分析了信道互藕和不平衡庄织寸干涉式综合孔径微波辐射计复相关干涉测量的影响.分析表明干涉测量误差的主要来源是信道的相位不平衡度.实现信道中心频率的相位精度就可以保证干涉相位的精度,而通道内的残余相位差只会引起干涉相关度的降低.通过相干/不相干噪声校准,就可以对信道不平衡引起的干涉相关测量误差进行修正.参5(金)国内外在成象光… 相似文献
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干涉式辐射计通过多通道间的相关运算得到被动亮温图像。对于亚毫米波段(submillimeter-wave, SMMW)相关运算对硬件系统的精度与相位稳定性提出了很高的要求。本文中,通过特殊设计的高精度SMMW器件,实现了一套基于二单元干涉仪的干涉式辐射计系统。针对该系统的自身特点,作者提出了点源目标响应定标方法来降低系统误差。系统完成后,分别进行了干涉条纹实验和点源目标成像实验。经测试,系统的线性相位误差小于2°,角分辨率优于0.57°。系统实测性能和理论分析结果一致。以上研究为今后设计高分辨率亚毫米波干涉式成像辐射计提供了重要的参考价值。 相似文献
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《红外与毫米波学报》2016,(6)
通过特殊设计的高精度SMMW器件,实现了一套基于二单元干涉仪的干涉式辐射计系统.针对该系统的自身特点,作者提出了点源目标响应定标方法来降低系统误差.系统完成后,分别进行了干涉条纹实验和点源目标成像实验.经测试,系统的线性相位误差小于2°,角分辨率优于0.57°.系统实测性能和理论分析结果一致.以上研究为今后设计高分辨率亚毫米波干涉式成像辐射计提供了重要的参考价值. 相似文献
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分析了综合孔径微波辐射计光学实时信号处理系统的基本原理及关键技术,研制了一套X波段6单元综合孔径红外实时信号处理系统样机,并进行了系统测试及点辐射源的一维实时成像实验,获得了清晰的干涉条纹图像.初步的实验结果验证了综合孔径辐射计光学实时信号处理的可行性及系统设计的正确性. 相似文献
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华中科技大学电磁场与微波技术中心已经设计并研制出一套工作于Ka波段的16阵元一维毫米波综合孔径辐射成像系统HUST-ASR,样机采用了最小冗余稀疏直线阵列以及先进的数字相关技术。阵列幅相误差对综合孔径辐射计成像会产生严重影响,文中提出一种不增加系统硬件复杂度、易于实现的单外部辅助源校正方法,给出在辐射计低信噪比条件下的校正算法,并进行了成像试验验证。试验结果表明,该校正方法能够有效校正毫米波综合孔径辐射计的幅相误差,经过校正后的成像系统对自然场景实现了非常清晰的毫米波综合孔径亮温图像,空间分辨率达到0.64°,证明该系统具有良好的成像性能。 相似文献
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The Technical University of Denmark (TUD) Synthetic Aperture Radiometer (SARad) is a two-channel demonstration model that can simulate a two-dimensional (2D) thinned array radiometer having an unfilled aperture populated with several small antenna elements. Aperture synthesis obtained by interferometric measurements using the antenna elements in pairs, followed by an image reconstruction based on an inverse Fourier transform, results in an imaging instrument without the need of mechanical scan. The thinned aperture and the nonscanning feature make the technique attractive for spaceborne radiometer systems, especially at low frequencies. The TUD SARad demonstration model consists of a two-channel Ku-band correlation radiometer with two horn antennas and an antenna mounting structure enabling the horns to be mounted in relevant positions within a certain aperture. A total aperture synthesis is obtained by sequentially placing the two antenna elements in all required pairs of positions and measuring the corresponding samples of the visibility function. The system has been used to demonstrate 2D synthetic aperture imaging of complex targets in outdoor ground experiments, a special feature of the system is that it uses a focused antenna system, thus enabling a short distance to the target. Set still utilizing image reconstruction algorithms identical to those used in a normal far-field situation. The aperture synthesis theory is discussed, with special emphasis on focused systems; the radiometer system is described; and images suitable for demonstration of resolution and other imaging properties are presented and discussed 相似文献
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Guangfeng Zhang Zuyin Zhang Wei Guo 《Journal of Infrared, Millimeter and Terahertz Waves》2004,25(5):845-853
A synthetic aperture radiometer is a new type of passive remote sensing instrument that can reach high spatial resolution. Restricted by antenna element size and operating wavelength, however, the system design is difficult at MMW band. In this paper, main technical parameters optimization of a synthetic aperture radiometer is discussed. Based on low-redundancy linear arrays, a millimeter wave synthetic aperture radiometric imaging scheme is presented. The simulation experimental results show that the system imaging effect depends on the synthetic aperture antenna pattern. 相似文献
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Martin-Neira M. Suess M. Kainulainen J. Martin-Porqueras F. 《Geoscience and Remote Sensing, IEEE Transactions on》2008,46(3):613-620
This paper describes a practical method to calibrate the microwave imaging radiometer with aperture synthesis (MIRAS) in orbit using external targets. Together with the in-orbit validation of the antenna patterns, the method ensures the generation of valid and calibrated visibilities from raw measurements with minimum impact from instrument errors, particularly antenna errors. It has been possible to devise this strategy only after the derivation of the Corbella equation, which correctly describes how MIRAS works. The proposed in-orbit calibration and validation approach is fully based on this equation. In a markedly different way to the point target response method used to calibrate other imaging systems, the technique put forward is essentially based on measuring a ldquoflatrdquo target such as the cold sky near the Galactic poles. This is why it has been called the ldquoflat target transformationrdquo. 相似文献
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Ke Chen Yaoting Zhu XiChen Guo Wei Guo QingXia Li LiangQi Gui Wei Ni 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(6):724-734
An aperture synthetic radiometer (ASR) based on interferometric technology is a new type of passive microwave imaging instrument,
which has high spatial resolution. Restricted by devices performance and operating wavelength, however, the system design
is difficult at MMW band. In this paper, an 8mm-band aperture synthetic radiometric imaging system based on minimum-redundancy
linear array is described, the performance specification of the instrument is analyzed. The preliminary imaging experiment
result shows that the system has good passive MMW imaging (PMMWI) performance, indicating a bright outlook for the development
of this technique in the future. 相似文献
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微波成像辐射计用于大气微波遥感、海洋微波遥感和陆地微波遥感;是气象、海洋和灾害监测的重要遥感手段之一。微波
成像辐射计在轨运行时能否获取有价值的探测资料,得到定量化的应用和真正的业务使用,主要取决于微波成像仪能否进行精确定
标。本文主要介绍了星载微波成像辐射计目前国际上通常采用的两种定标方法,馈源口面定标方法和天线口面定标方法,并对这两
种方法进行了比较和研究。 相似文献