GPS-R技术是一种全新概念的遥感方式,是人们在使用GPS时为了克服多路径效应问题而发现目标物对GPS的反射信号也可以被接收和利用,从而开辟了这个新的研究领域。人们把基于GPS-R反射信号的遥感技术,简称全球定位系统反射信号遥感技术(Glo...GPS-R技术是一种全新概念的遥感方式,是人们在使用GPS时为了克服多路径效应问题而发现目标物对GPS的反射信号也可以被接收和利用,从而开辟了这个新的研究领域。人们把基于GPS-R反射信号的遥感技术,简称全球定位系统反射信号遥感技术(Global Position System-Reflection,GPS-R)。本文主要研究GPS-R反射信号的反射点位置,为相关技术研究提供技术支持。展开更多
In order to realize the micromation of position sensors, and extend the application area into micro scale, this paper designs a novel micro position sensor, Mace SAW (Surface Acoustic Wave) position sensor, which can ...In order to realize the micromation of position sensors, and extend the application area into micro scale, this paper designs a novel micro position sensor, Mace SAW (Surface Acoustic Wave) position sensor, which can be fabricated with MEMS technology. Its key components are IDTs (Interdigital Transducers) and reflective grooves. The structure and working principles of the sensor are introduced theoretically, and the manufacture process is then put forward.展开更多
For the primary mirror of a large-scale telescope, an electro-hydraulic position control system(EHPCS) is used in the primary mirror support system. The EHPCS helps the telescope improve imaging quality and requires a...For the primary mirror of a large-scale telescope, an electro-hydraulic position control system(EHPCS) is used in the primary mirror support system. The EHPCS helps the telescope improve imaging quality and requires a micron-level position control capability with a high convergence rate, high tracking accuracy, and stability over a wide mirror cell rotation region. In addition, the EHPCS parameters vary across different working conditions, thus rendering the system nonlinear. In this paper, we propose a robust closed-loop design for the position control system in a primary hydraulic support system. The control system is synthesized based on quantitative feedback theory. The parameter bounds are defined by system modeling and identified using the frequency response method. The proposed controller design achieves robust stability and a reference tracking performance by loop shaping in the frequency domain. Experiment results are included from the test rig for the primary mirror support system, showing the effectiveness of the proposed control design.展开更多
文摘GPS-R技术是一种全新概念的遥感方式,是人们在使用GPS时为了克服多路径效应问题而发现目标物对GPS的反射信号也可以被接收和利用,从而开辟了这个新的研究领域。人们把基于GPS-R反射信号的遥感技术,简称全球定位系统反射信号遥感技术(Global Position System-Reflection,GPS-R)。本文主要研究GPS-R反射信号的反射点位置,为相关技术研究提供技术支持。
文摘In order to realize the micromation of position sensors, and extend the application area into micro scale, this paper designs a novel micro position sensor, Mace SAW (Surface Acoustic Wave) position sensor, which can be fabricated with MEMS technology. Its key components are IDTs (Interdigital Transducers) and reflective grooves. The structure and working principles of the sensor are introduced theoretically, and the manufacture process is then put forward.
基金supported by the National Basic Research Program(973)of China(No.2013CB035400)the National High-Tech R&D Program(863)of China(No.2012AA041803)the National Natural Science Foundation of China(No.51221004)
文摘For the primary mirror of a large-scale telescope, an electro-hydraulic position control system(EHPCS) is used in the primary mirror support system. The EHPCS helps the telescope improve imaging quality and requires a micron-level position control capability with a high convergence rate, high tracking accuracy, and stability over a wide mirror cell rotation region. In addition, the EHPCS parameters vary across different working conditions, thus rendering the system nonlinear. In this paper, we propose a robust closed-loop design for the position control system in a primary hydraulic support system. The control system is synthesized based on quantitative feedback theory. The parameter bounds are defined by system modeling and identified using the frequency response method. The proposed controller design achieves robust stability and a reference tracking performance by loop shaping in the frequency domain. Experiment results are included from the test rig for the primary mirror support system, showing the effectiveness of the proposed control design.
文摘在国外学者关于多焦点抛物面天线设计思想的基础上,针对多波束天线设计中各馈源位置已知的情况,提出了一种改进的多焦点抛物面天线设计方法。利用其对反射面进行赋形,设计了馈源位于±270 mm,±150 mm,0 mm的五焦点抛物面天线,通过优化基础抛物面加权系数,使得边缘波束与中心波束之间的增益差与标准反射面相比减少了0.76 d Bi和0.2 d Bi,使得覆盖区域内每个波束的增益趋于平均,并且满足低旁瓣的要求。
