Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：干涉仪利用通道间的相关运算进行测量，是干涉式成像的基本单元。太赫兹成像在安全检查、军事侦查等方面有着广泛的应用前景。将干涉成像测量引入太赫兹领域后，为解决相关运算中高速信号的相位同步问题，该文提出基于低速FPGA控制的交叉同步方案，用低硬件代价解决高速采样信号的相位同步问题，并完成了一套多通道高速数字相关系统。系统的最高采样速率为 5GHz，ADC有效位数大于等于6位，相关器积分时间可调。最后，利用该数字相关器和相应的太赫兹微波元器 件搭建了中心频率为 0.44THz的干涉仪，并得到了清晰的干涉条纹，其线性相位误差小于2°。该研究为今后设计太赫兹干涉成像仪提供了基本单元。
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：本文基于灵敏型地基相干高频雷达（AgileDARN）系统，回顾了空间电离层探测的研究背 景，简要介绍了 AgileDARN 雷达系统。对其数字信号处理系统进行了分析，阐述了系统发射信号产生 模块、回波信号处理模块的工作流程，设计数字系统的硬件结构，详细分析了系统发射信号多脉冲序 列产生的机制，回波信号处理的详细步骤，利用 FPGA 实现原始信号的产生，阵列天线信号波束合成 处理，以及系统中数字滤波器的设计，并通过仿真实验验证了 FPGA 设计的可行性和有效性，满足了 AgileDARN 雷达数字系统的设计要求。
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The space sience development strategy and plan of major space powers have evolved in several aspects, with the new progress in science and technology achieved in recent years. Committee on Science, Space and Technology in U.S. House was established in 2011. NASA created two new mission directorates named Human Exploration and Operation, and Space Technology. Space shuttles retired in 2011 after thirty-year service, and U.S. private space flight program and Mars robotic project have made great progress. The Global Exploration Roadmap and Decadal Survey in various disciplines of space science have been issued, with the priorities of space science missions planned to be implemented in next decade ranked. European Space Agency has signed Accession Agreement with Romania, Poland, Estonia, and Hungary, which made the number of its member states up to 22, and its space science missions of different classes (L, M, S and etc.) in Cosmic Vision 20152025 have been down-selected, with the selected ones successively put into implementation. Russian Federal Space Agency and Russian space industy have been under reform since 2011. Russian space activites carried out before 2020 were planned with its national plan issued in 2013, according to which Russian space budget will increase substaintially. As to Japan, Space Strategy Office was created in Japan Cabinet Office in 2012 to supervise overall space programs, which have continuously made breakthroughs. India has taken a rapid pace in Moon exploration and Mars program, and its space programs budget has increased continuously. Several features of internantional space science development strategy stand out and can be summarized as follows:investment in space science remains continuously stable, and major space powers have revised their space science plans or issued new ones;new space departments have been created or reformed to enhance efficiency;private sectors were encouraged to be involved in space flight activities to promote economic benefit;international cooperation has been further expanded. Space science plays a significant role in the whole national stategy. It is expected that Chinas space science plays a more and more important role in implementing our national innovation-driven development strategy.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The earth is the cradle of mankind, but human beings cannot live in the cradle forever. The launching of the first man-made satellite in 1957 by USSR indicates the kick-off of space era, which also brought up a new discipline of science Space Science. Though young as it is, space science mainly focuses on the old questions such as the origin and evolution of universe and life, the evolution of solar system and its planets, the laws of solar activity, and the evolution of the planet earth, the answers of which have been sought by human beings for thousands of years. The development of space era enables human beings to have access to space. With no disturbance and shielding of the earth atmosphere, the universe could be viewed and explored in a new way. Space science, usually taking satellites or spacecraft as platforms for observations and experiments, studies the phenomenon and laws of physics, astronomy, chemistry and life, etc. in the universe. In recently rough 60 years, through space scientific exploration and research, plenty of significant discoveries and breakthroughs had been made and our knowledge of universe had been transformed, so that the textbooks have been rewritten periodically. Meanwhile, the development of space science is close-related to the development of space technology. With the implementation of space science missions, the space and related technologies have been advanced greatly, many new fields have been opened up, and several generations of young people have been inspired to seek the dreams of new frontiers for science and technology. Space science, which has been in a race in developed countries, plays an important and strategic role in national development, and is remarked as the generator of wealth, driver of innovation, and the source of new theory and knowledge.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： After the half-a-century development, space science has not only explored and settled new frontiers, expanding humans understanding about nature and human itself, but also lead the rapid development of space and related technologies, and also brought about a number of innovative applications, which has been advancing national scientific, security, economic and social interest and human life quality. China has laid a certain foundation in space science research through 50 years of development. In 2011, the go-ahead of Strategic Priority Program (SPP) on Space Science marked that China's space science had entered a new stage. With an analysis of domestic space science status as the beginning, the paper poses the scientific questions to be addressed by Chinese space science community in 20162030, which is a) how did matter originate, how does it evolve and move? b) whats the relationship between the solar system and human beings? Besides, The Chinese space science strategic goal is proposed, i.e. to make great scientific discoveries and achieve innovative breakthroughs by a series of scientific satellite programs and missions in frontier scientific fields, such as the formation and evolution of the universe, the exploration of exoplanets and extraterrestrial life, the formation and evolution of the solar system, solar activities and their impact on the earths space environment, the development and evolution of the earths system, new physics beyond the current basic physics theories, the law of matter motion and the law of life activity in space environment, etc;and to drive the great-leap-forward of aerospace and related high technologies. In addition, the paper also proposes the space science programs and missions through 2030, and probes into the supporting technical capability. Through the implementation of a series of space science programs and missions, it is expected to make due contribution to Chinas economic and social development and humans civilization.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： A method using Simulink to build the simulation model of the microwave interferometric radiometer(MIR)system is introduced in this paper.Two-element interferometer is the basic unit of the MIR system. By the Simulink platform,a simulation model of the two-element interferometer was built and the measurement process of the random noise was simulated.Through the simulation of the full power measurement achieved interference measurement of single channel and two channels.Quantitative analysis of the radiometric accuracy and radiometric sensitivity were achieved in the time domain.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The inverse imaging is a key issue for microwave interferometric radiometers,but the inverse process is ill-posed and doesnt provide a unique and stable solution.For the problem that there exists a large reconstruction bias with G matrix model used generally in the inversion algorithm,an improved G matrix model applied in FPIR system was presented.The simulation results show that,compared with conventional G matrix model,the improved G matrix model can greatly reduce the reconstruction bias in the FPIR system.The improved G matrix model can obtain more accurately the brightness temperature distribution of the observed scene,so as to meet requirements of measuring wind field of the ocean surface and soil moisture for FPIR.
Peer Review Status:Awaiting Review
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