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针对一些小型试验场或舰船上的条件局限性,对授时、控制等参试设备提出了更高的要求,希望提供一种功能全面、携带方便的小型化设备,用以满足试验的多种需求.为解决这个问题,研制了新一代时统设备——卫星授时控制器.基于GPS(全球定位系统)/BDS-Ⅱ(“北斗”二代)卫星授时原理,采用功能较强的微控制器和可编程器件产生多种时频信号、控制信号和模拟导航信息,实现了定时、控制、接收和产生等多重功能,提高了设备的集成性、通用性和便携性;同时采用倍频、锁相、驯服等技术,使设备10 MHz频率源的准确度提高2个量级,卫星同步精度优于50 ns.该控制器已成功应用于移动测控站和舰船试验中,效果良好. 相似文献
713.
冯永胜 《民用飞机设计与研究》2013,(1):40-41,47
首先介绍了进行某民用飞机起落架地面舱门打开机构分析的背景和目的。然后从功能、组成、布置、工作原理、能源供给、安全装置和操作程序等方面对地面舱门打开机构进行详细分析。最后得出8个可供国内民用飞机起落架地面舱门打开机构设计参考的结论。 相似文献
714.
张陇东 《民用飞机设计与研究》2013,(4):6-9,63
世界上各个国家和地区的适航管理机构和体系,其工作内容和性质是一致的,但由于各国民用航空产业发展程度不一,研制民航产品的能力有别,以及各国的管理办法和习惯做法的差异,导致各国适航管理的体系和机构在名称、规模和工作方式上常常不一样,这其中,以美国和欧洲两套体系最具代表性。 相似文献
715.
主要介绍使用基于Ti Davinci架构的图像处理SDK软件系统设计.软件系统运行于基于TMS320DM6467的智能交通专用主机,支持智能交通领域的多种图像处理算法,算法运行于DSP核心,通过ARM与DSP核心间RPC机制,使ARM运行的应用软件可透明地调用相应算法.针对嵌入式系统的有限内存,系统分别在ARM和DSP核心端完成内存优化.针对DSP核心的硬件架构架构,实现相关算法的指令优化.系统可应用于智能交通领域多种系统的开发. 相似文献
716.
Zhouzheng Gao Tuan Li Hongping Zhang Maorong Ge Harald Schuh 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(9):2393-2405
Since China’s BeiDou satellite navigation system (BDS) began to provide regional navigation service for Asia-Pacific region after 2012, more new generation BDS satellites have been launched to further expand BDS’s coverage to be global. In this contribution, precise positioning models based on BDS and the corresponding mathematical algorithms are presented in detail. Then, an evaluation on BDS’s real-time dynamic positioning and navigation performance is presented in Precise Point Positioning (PPP), Real-time Kinematic (RTK), Inertial Navigation System (INS) tightly aided PPP and RTK modes by processing a set of land-borne vehicle experiment data. Results indicate that BDS positioning Root Mean Square (RMS) in north, east, and vertical components are 2.0, 2.7, and 7.6?cm in RTK mode and 7.8, 14.7, and 24.8?cm in PPP mode, which are close to GPS positioning accuracy. Meanwhile, with the help of INS, about 38.8%, 67.5%, and 66.5% improvements can be obtained by using PPP/INS tight-integration mode. Such enhancements in RTK/INS tight-integration mode are 14.1%, 34.0%, and 41.9%. Moreover, the accuracy of velocimetry and attitude determination can be improved to be better than 1?cm/s and 0.1°, respectively. Besides, the continuity and reliability of BDS in both PPP and RTK modes can also be ameliorated significantly by INS during satellite signal missing periods. 相似文献
717.
Min Chen Sufang DengYouquan Yang Yibing HuangChongchu Liu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
Azolla shows high growth and propagation rates, strong photosynthetic O2-releasing ability and high nutritional value. It is suitable as a salad vegetable and can be cultured on a multi-layered wet bed. Hence, it possesses potential as a fresh vegetable, and to release O2 and absorb CO2 in a Controlled Ecological Life Support System in space. In this study, we investigated the O2-providing characteristics of Azolla in a closed chamber under manned, controlled conditions to lay a foundation for use of Azolla as a biological component in ground simulation experiments for space applications. A closed test chamber, representing a Controlled Ecological Life Support System including an Azolla wet-culture device, was built to measure the changes in atmospheric O2 and CO2 concentrations inside the chamber in the presence of coexisting Azolla, fish and men. The amount of O2 consumed by fish was 0.0805–0.0831 L kg−1 h−1 and the level of CO2 emission was 0.0705–0.0736 L kg−1 h−1; O2 consumption by the two trial volunteers was 19.71 L h−1 and the volume of respiration-released CO2 was 18.90 L h−1. Under 7000–8000 Lx artificial light and Azolla wet-culture conditions, human and fish respiration and Azolla photosynthesis were complementary, thus the atmospheric O2 and CO2 concentrations inside chamber were maintained in equilibrium. The increase in atmospheric CO2 concentration in the closed chamber enhanced the net photosynthesis efficiency of the Azolla colony. This study showed that Azolla has strong photosynthetic O2-releasing ability, which equilibrates the O2 and CO2 concentrations inside the chamber in favor of human survival and verifies the potential of Azolla for space applications. 相似文献
718.
Xing Meng Hanxian Fang Libin Weng Zhendi Liu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(7):2118-2125
Through concurrently measurements by Communication/Navigation Outage Forecasting System (C/NOFS), Sanya VHF radar and GPS ionospheric scintillation receiver on 12 March 2010, five plasma bubbles were found and three of them were observed by all those instruments. Two well-developed plumes with strong backscatter echoes were measured by Sanya radar and their corresponding depletions were observed by C/NOFS in Orbit 10317, 10318 and 10319. Broad plasma depletions resulting from merging process were found in orbit of 10318. The occurrence time and geophysical positions of scintillations correlate well with observations implemented by Sanya VHF radar and C/NOFS. Observations from three types of instrument indicate that the spread F irregularities have distinct scale. There were longitudinal differences between Sanya VHF radar and C/NOFS as irregularities measured, and the eastward drift of developed bubbles are responsible for these differences. 相似文献
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