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排序方式: 共有2198条查询结果,搜索用时 46 毫秒
971.
972.
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
973.
SAR卫星用能量功率兼顾型锂离子电池研究 总被引:3,自引:3,他引:0
未来大功率合成孔径雷达(SAR)卫星的发展对储能电池组提出了轻量化、倍率高及在轨寿命长等要求,而现有的SAR卫星用功率型锂离子电池产品已无法满足未来需求。通过优化正极材料和电池设计,加入功能电解液,在保证电池功率特性的同时,显著提升了电池的能量密度和循环稳定性。本文研制出的新一代能量功率兼顾型锂离子蓄电池,额定容量为25.0 Ah,初期放电比能量达到180.0 Wh·kg~(-1),2 C放电容量为0.2 C容量的91.0%,1 C-100%放电深度(DOD)和2 C-30%DOD循环性能优异,可以满足下一代大功率SAR卫星的供配电需求,且大幅降低了电源系统重量,提高了卫星储能系统的利用率和平台有效载荷能力。 相似文献
974.
975.
Antonella A. Albuja Daniel J. Scheeres Rita L. Cognion William Ryan Eileen V. Ryan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2018,61(1):122-144
The Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect is a proposed explanation for the observed rotation behavior of inactive satellites in Earth orbit. This paper further explores the YORP effect for highly asymmetric inactive satellites. Satellite models are developed to represent the GOES 8 and GOES 10 satellites, both of which are currently inactive in geosynchronous Earth orbit (GEO). A simple satellite model for the GOES 8 satellite is used to analyze the short period variations of the angular velocity and obliquity as a result of the YORP effect. A more complex model for the rotational dynamics of the GOES 8 and GOES 10 satellites are developed to probe their sensitivity and to match observed spin periods and states of these satellites. The simulated rotation periods are compared to observations for both satellites. The comparison between YORP theory and observed rotation rates for both satellites show that the YORP effect could be the cause for the observed rotational behavior. The YORP model also predicts a novel state for the GOES 8 satellite, namely that it could periodically fall into a tumbling rotation state. Recent observations of this satellite are consistent with this prediction. 相似文献
976.
C.J. Rodriguez-Solano U. HugentoblerP. Steigenberger 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
One of the major uncertainty sources affecting Global Positioning System (GPS) satellite orbits is the direct solar radiation pressure. In this paper a new model for the solar radiation pressure on GPS satellites is presented that is based on a box-wing satellite model, and assumes nominal attitude. The box-wing model is based on the physical interaction between solar radiation and satellite surfaces, and can be adjusted to fit the GPS tracking data. 相似文献
977.
为提高卫星系统整体性能与优化设计效率,本文采用多学科设计优化(MDO)方法进行全电推进卫星总体参数优化。主要考虑轨道转移、位置保持、空间环境、供配电、结构及质量六个学科,以整星质量最小为优化目标,考虑轨道转移时间等约束条件,建立了全电推进卫星MDO模型。提出一种基于增广拉格朗日乘子法的高效全局优化方法(ALM-EGO)以快速求解卫星MDO问题。标准数值算例对比研究表明,对于处理高耗时约束优化问题,ALM-EGO方法在全局收敛性与优化效率方面具有一定的优势。最后,采用ALM-EGO求解全电推进卫星MDO问题,优化后的全电推进卫星设计方案满足各类工程设计约束,实现整星减重161.09 kg,从而验证了本文所建立模型的合理性和ALM-EGO方法的有效性。 相似文献
978.
Spin rate and spin axis orientation of LARES spectrally determined from Satellite Laser Ranging data
D. Kucharski T. Otsubo G. Kirchner G. Bianco 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
Satellite Laser Ranging (SLR) is a powerful technique able to measure spin rate and spin axis orientation of the fully passive, geodetic satellites. This work presents results of the spin determination of LARES – a new satellite for testing General Relativity. 529 SLR passes measured between February 17 and June 9, 2012, were spectrally analyzed. Our results indicate that the initial spin frequency of LARES is f0 = 86.906 mHz (RMS = 0.539 mHz). A new method for spin axis determination, developed for this analysis, gives orientation of the axis at RA = 12h22m48s (RMS = 49m), Dec = −70.4° (RMS = 5.2°) (J2000.0 celestial reference frame), and the clockwise (CW) spin direction. The half-life period of the satellite’s spin is 214.924 days and indicates fast slowing down of the spacecraft. 相似文献
979.
连线端站干涉测量(connected element interferometry,CEI)是高精度测角技术,在中高轨卫星、月球及深空航天器定轨定位中有良好的应用前景。基于CEI技术特点,提出了一种新的测量方法,即在相干测距模式下利用测距音和载波信号作为信号源进行连线端站干涉测量。构建了CEI试验系统对北斗GEO卫星进行观测,利用相干测距模式下的下行信号解算群时延、相时延。利用北斗GEO卫星精密星历计算的时延理论值,对北斗GEO卫星CEI群时延和相时延结果进行评估。结果表明,相干测距模式下CEI群时延和相时延残差均值分别为0.47ns、0.08ns,标准差(3σ)分别4.2ns、0.13ns。该项研究验证了相干测距模式下CEI相时延解算的可行性,可为共位地球同步卫星精密相对定位、月球探测器CEI测量提供技术参考。 相似文献
980.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(10):2348-2359
On December 27, 2018, the Beidou-3 System (BDS-3) has completed the deployment of 18 Medium Earth Orbit (MEO) satellites combined as a space constellation. In addition to the augmentation information for the new system signals B1C and B2a, the BDS-3 is compatible with the three augmentation information broadcast by the BDS-2 system for B1I and B3I signals: equivalent clock error correction, User Differential Ranging Error (UDRE) and Grid Ionosphere Vertical Error (GIVE). In this paper, the observation data of Beidou monitoring network are used to analyze the pseudo-range observation quality of the smooth transition signals B1I and B3I of BDS-2 and BDS-3. At the same time, the relationship between the equivalent clock error correction and the prediction error of the satellite clock is analyzed by using the Two-Way Satellite Time and Frequency Transfer (TWSTFT) data. The results show that the correlation between the equivalent clock error correction and the monitored clock error by using the TWSTFT data is greater than 60%. We calculate the UDRE by using the equivalent clock error correction. The results show that the satellite equivalent clock error correction can improve the accuracy of User Equivalent Range Error (UERE) by about 50%. This paper also compares the positioning accuracy of the BDS-2 satellites with the BDS-2 satellites combined BDS-3 satellites. The results show that the three-dimensional positioning accuracy is improved by about 30% after the BDS-3 satellites are added. 相似文献