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L波段二次测风系统是气象探测的主力设备,对该系统而言接收的信噪比是改善测量精度的关键。为了达到这个目的,该文设计了一种全新体制的L波段二次测风雷达系统。其系统采用单脉冲和相扫技术,提高了测量精度。文中主要从信噪比角度出发对该系统的测量精度进行了分析,并得出了该系统性能符合指标要求的结论。 相似文献
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《中国无线电电子学文摘》2000,(6)
TN95 00061401监视雷达网效能评价研究(续)一一第二部分:监视雷达网抗干扰效能评估/丽阵能敬(空军第二所)11现代雷达一2000,22(2).一1一10图3参6(许)方向.图4表1(许)TN95 00061402L波段二次测风雷达的系统设计/黄增兴(南京电子技术研究所)11现代雷达.一2000,22(2).一11一24,22二测风雷达是大气探测的重要工具之一文中主要介绍二次测风雷达的主要技术要求、工作原理、系统方案设计与计算分析,同时简述与二次测风雷达配套的电子探空仪的工作原理和技术要求.图3参2(许)TN95 00061404实时多任务操作系统及其在机载相控阵雷达系统中的开发应用… 相似文献
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为分析在1668~1675 MHz频段引入卫星移动系统的可行性,对该频段卫星移动系统与无线电探空系统间的兼容共存问题进行了深入分析。介绍了两个无线系统的基本特征和主要参数,讨论了两系统间潜在的干扰链路。针对卫星移动业务终端对二次测风雷达的干扰以及二次测风雷达对卫星空间电台的干扰两条主要干扰链路,采用计算机静态建模和蒙特卡洛仿真方法,对干扰情况进行了计算仿真。仿真结果表明,在卫星终端密度在50个/km2时,二次测风雷达所需的保护距离为60~80 km,而单个二次测风雷达主瓣方向发射二次测风雷达的功率高于空间卫星国际保护标准达60 d B。该研究结果可为我国无线电管理部门对该频段的重新规划提供支撑。 相似文献
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二次测风雷达是大气探测的重要工具之一.本文主要介绍二次测风雷达的主要技术要求、工作原理、系统方案设计与计算分析,同时简述与二次测风雷达配套的电子探空仪的工作原理和技术要求. 相似文献
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风廓线雷达作为一种新型的大气风场探测设备,具有时间分辨率高、连续性和实时性好等特点,已广泛应用到各行业。文中首先分析了增程型L 波段风廓线雷达的探测能力,简要介绍了该雷达的系统设计;然后,利用中国气象局海口站业务运行一年的观测数据,从探测高度和数据准确率等方面对雷达探测性能进行了统计分析。结果表明:增程型L 波段风廓线雷达满足设计指标要求,可用于低对流层大气风场的观测。 相似文献
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1.概述
空管雷达系统是一种为确保飞机飞行安全和提高飞行效率而建立的雷达系统。它包括一次监视雷达(PSR)、二次监视雷达(SSR)、精密进场雷达(PAR)、场面监视雷达和气象雷达。一次监视雷达包括航路监视雷达和机场监视雷达。航路监视雷达(如美国雷声公司的ASR-23SS)是一种远程搜索雷达,一般工作在L波段,主要用于区域管制, 相似文献
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由于2m波段激光处于大气的窗口上,并且对人眼安全,因而在测风领域具有潜在的应用价值。该波段的激光器可以作为相干多普勒测风雷达和差分吸收雷达的光源。为了进行相干多普勒测风雷达光源的研究,报道了一种脉冲激光二级管(LD)单端抽运Tm:YAG调Q激光器。在实验中,采用L型平凹腔结构,利用声光Q开关实现大能量的激光输出。该激光器输出的激光中心波长为2 014.9 nm,在重复频率为100 Hz情况下,调Q后获得最大单脉冲能量为6.11 mJ,激光脉冲宽度为324.7 ns,斜率效率为13.56%的激光输出。输出的脉冲激光的光束质量M2在x方向上为1.31,y方向上为1.35。 相似文献
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Spaceborne single-polarization C-band synthetic aperture radar (SAR) imagery is widely used to gather information about the state of the sea ice cover in the polar regions. C-band is regarded as a reasonable choice for all-season monitoring capabilities. For specific mapping tasks, however, other frequency bands can be more suitable. In the first part of this paper, the summary of a literature study dealing with the utilization of L-band SAR imagery for sea ice monitoring is presented. Investigations reveal that if deformation features such as ice ridges, rubble fields, and brash ice are to be mapped, L-band radar is superior in a number of cases. The second part of this paper addresses the comparison of JERS-1 and ERS-1 SAR images that were acquired over sea ice east of Svalbard and along the east coast of Greenland. The effects of the different frequencies, polarizations, and incidence angles of the two SAR systems are discussed. It is demonstrated that the images of both sensors complement one another in the analysis of ice conditions, resulting in a more detailed view of the sea ice cover state. 相似文献
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L-带掺铒光纤放大器的研究与进展 总被引:6,自引:1,他引:5
通过理论计算,比较了C-带掺铒光纤放大器和L-带掺铒光纤放大器的增益特性,并较为全面地阐述了近几年来国内外对L-带掺铒光纤放大器的研究情况。通过对L-带掺铒光纤放大器工作原理的分析,总结出新的设计思路与方案,提出了一些新的研究点。 相似文献
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微波双栅FET混频器的分析与设计 总被引:1,自引:1,他引:0
蔡水银 《固体电子学研究与进展》1985,(2)
本文分析了双栅FET的混频机理,给出了双栅FET的三种非线性模型.介绍了采用三端口阻抗条件设计双栅FET混频器的方法.在S、L波段制作的两种双栅FET混频器,噪声系数略高于二极管混频器,而变频增益比二极管混频器高10dB.整机应用结果表明,它具有简化电路、降低成本和对前置中放噪声系数要求不高的优点. 相似文献
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Liou Y.-A. Chen K.-S. Wu T.-D. 《Geoscience and Remote Sensing, IEEE Transactions on》2001,39(1):129-135
L-band brightness predicted by the land surface process/radiobrightness (LSP/R) model for prairie grassland appears to be somewhat lower than expected. A crucial reason for the underestimate of the L-band brightness is that the soil surface was treated as smooth. In this paper, surface scattering of the soil determined by the IEM model is incorporated into the LSP/R model to examine its impact on the predicted L-band brightness. Eight sets of surface parameters, two correlation lengths (L) of 3 and 6 cm×4 root mean squared (RMS) heights (σ) of 0.3, 0.6, 0.8, and 1.0 cm, are utilized to characterize the emission of the soil surface. It is found that H-polarized, L-band brightness is expectedly increased by different levels for all of the eight rough surface cases compared to the smooth surface case. The increase in the average of the H-polarized, L-band brightness is by as much as 13.2 K for the case with L=3 cm and σ=1.0 cm. In addition, L-band's sensitivity to soil moisture is found to be approximately equal with and without the scattering effects. An increase in H-polarized, L-band brightness by about 12 K at the end of a 14-day simulation by the LSP/R model is in response to a decrease in soil moisture by 7% for all of the nine cases of concern (eight rough plus one smooth soil surfaces) 相似文献
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文章提出了一种基于三端口增益平坦滤波器、且在拓扑结构上不同于以往并行或串行结构的掺铒光纤放大器(EDFA)的新结构。理论模拟显示,同常规的并行结构EDFA相比,该新型结构在保证C波段EDFA性能的同时亦可将L波段掺铒光纤(EDF)用量减少48%以上,改善L波段泵浦效率55%以上。实验中,我们在C波段使用两只输出功率分别为106.9和109.6mW的980nm泵浦激光器,两段EDF的长度分别为8.5和9.6m,在L波段我们仅用1只80mW的1480nm泵浦激光器,EDF长度为19.8m。试验结果显示,在C+L波段内得到的信号增益〉23dB,增益平坦度〈0.6dB,噪声指数在C和L波段内分别〈4.4dB和5.6dB。 相似文献
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Improvement of Moisture Estimation Accuracy of Vegetation-Covered Soil by Combined Active/Passive Microwave Remote Sensing 总被引:1,自引:0,他引:1
Ulaby Fawwaz T. Dobson Myron C. Brunfeldt David R. 《Geoscience and Remote Sensing, IEEE Transactions on》1983,(3):300-307
The measured effects of vegetation canopies on radar and radiometric sensitivity to soil moisture are compared to first-order emission and scattering models. The models are found to predict the measured emission and backscattering with reasonable accuracy for various crop canopies at frequencies between 1.4 and 5.0 GHz, especially at angles of incidence less than 30°. The vegetation loss factor L (?) increases with frequency and is found to be dependent upon canopy type and water content. In addition, the effective radiometric power absorption coefficient of a mature corn canopy is roughly 1.75 times that calculated for the radar at the same frequency. Comparison of an L-band radiometer with a C-band radar shows the two systems to be complementary in terms of accurate soil moisture sensing over the extreme range of naturally occurring soil-moisture conditions. The combination of both an L-band radiometer and a C-band radar is expected to yield soil-moisture estimates that are accurate to better than +/-30 percent of true soil moisture, even for a soil under a lossy crop canopy such as mature corn. This is true even without any other ancillary information. 相似文献
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