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1.
大气臭氧地基遥感反演的退卷积方法   总被引:1,自引:0,他引:1  
本文提出了一种大气臭氧地基遥感信息处理的新方法,它利用非线性退卷积方法和等效仪器函数提高光谱分辨率,利用非线性最小二法进行大气臭氧反演计算,可以显著提高大气臭氧遥感的可探测高度和精度。  相似文献   

2.
本文讨论了总辐照度、大气透过率和程辐射亮度对遥感数据的影响。导出了不同高度的程辐射亮度表达式。给出了三个不同地区上述三参数在可见和近红外光谱区不同波段的观测结果。用相应的大气模式计算了不同高度的大气透过率及程辐射亮度。预计了0.4—0.5,0.5—0.6,0.6—0.7,0.7—1.1微米波段在不同大气条件和不同高度遥感器接收到的总辐射亮度、目标物本征辐射亮度和程辐射亮度。给出了总辐射亮度随程辐射亮度和目标物反射率的变化关系。分析了这些数据与大气条件的关系。  相似文献   

3.
太阳活动与热层大气密度的相关性研究   总被引:1,自引:2,他引:1  
为分析太阳活动对热层大气的影响,使用250 km,400 km,550 km高度处热层大气密度与太阳F_(10.7)指数数据,研究了二者的周期变化及相关关系.结果表明,热层大气密度的变化与太阳活动呈现相似的变化趋势;两者均具有显著的27天及11年周期变化特征,热层大气密度还存在7~11天及0.5年和1年的变化特征,且高度越高越明显;热层大气密度对太阳活动的最佳响应滞后为3天,无论何种地磁活动水平下,400 km高度处相关性高于250 km,550 km处相关性最小,且太阳活动下降相期间高于上升相;250 km,400 km和550 km高度处热层大气密度和太阳活动的统计结果分别为饱和,线性和放大关系;高度越高的热层大气密度对太阳活动响应越敏感.  相似文献   

4.
根据火星大气数据库,建立了以高度和经纬度为输入的火星三维解析大气密度模型;在竖直方向上,采用分层指数模型;在水平方向上,将指数模型中的参考密度和参考高度视为经纬度的多项式函数,并通过最小二乘曲面拟合得到了多项式系数。相比传统的指数模型,三维指数模型不仅反映了火星大气密度随高度的变化规律,而且能够体现出大气密度在水平方向上的变化。与大气数据库相比,三维密度模型具有解析形式,计算速度快,仿真过程中只需存储简单的多项式系数即可实现密度的实时计算和调用,适用于地面实时仿真。  相似文献   

5.
为了更加准确地进行异源遥感图像的变化检测任务,提出了一种基于混合网络的异源遥感图像变化检测算法。利用伪孪生网络提取异源遥感图像块间空间维度的变化特征,利用早期融合网络提取异源遥感图像块间光谱维度的变化特征,将2支网络提取的特征进行融合,并将融合后的变化特征输入到sigmoid层进行二分类检测。同时,在伪孪生网络中加入对比损失函数,通过优化对比损失函数,使得在特征空间中,未变化图像对的空间特征差异更小,变化图像对的空间特征差异更大,以提升网络的区分能力和收敛速度。   相似文献   

6.
日本宇宙开发事业团欲在1994年用H2火箭发射先进地球观测卫星(AD:EOS)后,于1997年再发射新的极轨道平台型卫星(JPOPS),旨在用各种遥感器观测地球环境。后者从1990年开始进入概念确定研究。新的地球观测卫星重5吨,在800公里高度的极轨道上运行,周期100分钟。平台型卫星将保留卫星公用舱的主要功能,其中有温控系统和电源系统。该先进地球观测卫星除保留原来的2种遥感器外,还选定了6种星上用的遥感器。这6种遥感器是:  相似文献   

7.
“快鸟”:高分辨率商业遥感卫星中的一颗新星   总被引:2,自引:0,他引:2  
遥感卫星或称地球观测卫星围绕地球运转,传回有科学和商业用途的图片,如今已不算什么新鲜事了。然而,高分辨率商业遥感卫星的出现,有可能给卫星遥感市场带来革命性的变化。因为在未来的岁月中,人们的生活将深受其影响。到2010年末,人们很可能都离不开商业遥感卫...  相似文献   

8.
1992年陆地遥感政策法令表明,美国目前对遥感技术的价值有了成熟的理解。长期以来,遥感政策已成为国家决策的焦点。利用国家遥感资产作为未来投资的时代业已开始。陆地卫星计划在过去10年里成为争论的主题。为美国遥感卫星商业化所做的绝大部分努力均告失败,然而这项新法律却正是正确导向最终全力利用陆地卫星及其数据的一个行动。新法律体现出一种新的姿态和新的观点: 承认遥感在全球环境变化研究中的价值;  相似文献   

9.
卫星遥感技术在发现、监测、识别、定位和分析地下核试验中具有不可替代的独特作用,且使得事先阻止核爆炸试验成为可能.地下核试验的卫星核查与遥感监测是一个高度复杂的综合决策过程.本文结合几个具体实例,介绍了其中一些有效的遥感分析识别技术,如图像序列分析、图像融合、变化检测、K-L变换、D-InSAR、数字三维地形、GIS数据库等.卫星遥感的局限性在于,其难以从物理上确认地下核爆炸事件且不可避免地存在虚警和漏警.  相似文献   

10.
介绍了地球表面上任意一点重力加速度的计算方法,得出了考虑地球、太阳和月球引力,海平面一定高度范围内的点位在一年和一昼夜中,不同的时间点重力加速度的计算公式。其中太阳引力和地球围绕太阳旋转相关的加速度分量在一昼夜时间内影响的方向会有变化,月球引力的影响较小,但影响的方向在昼夜间也是变化的,最终确定了地球表面上加速度的最大最小值。  相似文献   

11.
一种区域性中轨道卫星移动通信星座   总被引:1,自引:0,他引:1  
提出一种中轨道卫星移动通信星座 ,它可以提供包括中国在内的亚洲及太平洋地区的通信服务 ,最小观测仰角按 30°设计。该星座由 6颗周期为 12 h、倾角为 2 8.5°的圆轨道卫星组成 ,轨道高度为 2 0 183km,6颗卫星均布在同一条地面轨迹上。  相似文献   

12.
Dosimeter data taken on the APEX (1994–1996), CRRES (1990–1991) and DMSP (1984–1987) satellites have been used to study the low altitude (down to 350 km) radiation environment. Of special concern has been the inner edge of the inner radiation belt due to its steep gradient. We have constructed dose models of the inner edge of the belt from all three spacecraft and put them into a personal computer utility, called APEXRAD, that calculates dose for user-selected orbits. The variation of dose for low altitude, circular orbits is given as a function of altitude, inclination and particle type. Dose-depth curves show that shielding greater than 1/4 in Al is largely ineffectual for low altitude orbits. The contribution of outer zone electrons to low altitude dose is shown to be important only for thin shields and to have significant variation with magnetic activity and solar cycle.  相似文献   

13.
Since 1963 approximately 300 satellites have been launched into the geostationary orbit, followed possibly by another additional 200 satellites up to the year 2000. Ground surveillance with radar and optical sensors able to detect objects of 1 m minimum size in the geostationary ring indicates a total population of several hundred which includes active and defunct satellites and spent upper stages. In addition, a population of untrackable objects is conjectured, whose size can only be estimated, possibly several thousand of smaller objects.

The purpose of this paper is to review the long-term evolution of orbits in the geostationary ring and at higher altitude, the collision probabilities and disposition options.

The major perturbations are considered including attitude-orbit cross-coupling effects which could cause secular orbit perturbations.

Collision probabilities for current and projected populations are reviewed considering different approaches, such as a deterministic treatment of the uncontrolled population and a stochastic modeling for the controlled satellites. Also, colocation, that is sharing of the same longitude slot by several operational satellites, is a potential source for collision, if no preventive measures are taken.

As regards spacecraft disposition options, the conclusion is that reorbiting is currently the only practical measure to safeguard the geostationary orbit. In this recommended procedure the defunct satellites are inserted into a so-called graveyard orbit, located suffieciently high above the geostationary orbit.  相似文献   


14.
Preliminary results of the EU INTAS Project 00810, which aims to improve the methods of safeguarding satellites in the Earth’s magnetosphere from the negative effects of the space environment, are presented. Anomaly data from the “Kosmos” series satellites in the period 1971–1999 are combined in one database, together with similar information on other spacecraft. This database contains, beyond the anomaly information, various characteristics of the space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluences of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried out for the total number of anomalies (about 6000 events), and separately for high (5000 events) and low (about 800 events) altitude orbit satellites. No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and low (<1500 km) altitude orbits revealed a big difference in a behavior. Satellites were divided on several groups according to the orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found to be different for various orbits that should be taken into account under developing of the anomaly frequency models.  相似文献   

15.
16.
碎片清除飞行器异面变轨需要消耗大量燃料.从气动辅助异面变轨优化设计及被清除碎片轨道高度差值、倾角差值等参数对变轨性能的影响出发,比较分析了优化气动辅助异面变轨与双脉冲霍曼轨道转移的燃料节约量,研究了不同轨道高度差对于实施气动辅助变轨燃料节约量的影响.当地球静止轨道(GEO)与低地轨道(LEO)间气动辅助变轨优化速度增量约为1.55km·s-1、质量面积比172kg·m-2、比冲310s、轨道倾角变化16°时,燃料节约率约为45%.对比研究了不同轨道高度差LEO轨道间实施气动辅助变轨的燃料节约情况.结果表明:随着轨道高度的增加,气动辅助优化效率逐渐降低;在相同高度轨道间实施异面变轨,随着轨道倾角的增加,气动辅助变轨燃料节约率先增大后减小,倾角改变量约为20°时,燃料节约率最大;当轨道倾角为5°时,采用气动辅助变轨和双脉冲变轨的燃料消耗量相同.   相似文献   

17.
一种新的GPS星座选择算法   总被引:1,自引:0,他引:1  
在分析星座高度角和方位角对GPS定位误差影响的基础上,提出了一种新的最佳选星算法。理论分析和仿真结果表明:采用该方法选星作导航定位计算的误差和速度均优于以搜索4颗卫星组合的最小几何误差因子为计算准则的常规选星方法,且具有简单实用、工程易实现等优点,具有较强的适应性。  相似文献   

18.
The population of cataloged orbital debris increased by approximately 40% in just a couple of years, from January 2007 to February 2009. This was due to two collisions in space, which involved the catastrophic destruction of three intact satellites (Fengyun 1C, Cosmos 2251 and Iridium 33) in high inclination orbits. Both events occurred in the altitude range already most affected by previous launch activity and breakup events, thus boosting the cataloged population in low Earth orbit by more than 60%.  相似文献   

19.
The evolution of objects in geostationary transfer orbit (GTO) is determined by a complex interplay of atmospheric drag and luni-solar gravity. These orbits are highly eccentric (eccentricity >0.7) and have large variations in velocity and perturbations during a revolution. The periodic changes in the perigee altitudes of these orbits are mainly due to the gravitational perturbations of the Sun and the Moon. The re-entry time of the objects in such orbits is sensitive to the initial conditions. The aim of this paper is to study the re-entry time of the cryogenic stage of the Indian geo-synchronous launch vehicle, GSLV-F04/CS, which has been decaying since 2 September 2007 from initial orbit with eccentricity equal to 0.706. Two parameters, initial eccentricity and ballistic coefficient, are chosen for optimal estimation. It is known that the errors are more in eccentricity for the observations based on two line elements (TLEs). These two parameters are computed with response surface method using a genetic algorithm for the selected eight different zones, based on rough linear variation of the mean apogee altitude during 200 days orbit evolution. The study shows that the GSLV-F04/CS will re-enter between 5 December 2010 and 7 January 2011. The methodology is also applied to study the re-entry of six decayed objects (cryogenic stages of GSLV and Molniya satellites). Good agreement is noticed between the actual and the predicted re-entry times. The absolute percentage error in re-entry prediction time for all the six objects is found to be less than 7%. The present methodology is being adopted at Vikram Sarabhai Space Centre (VSSC) to predict the re-entry time of GSLV-F04/CS.  相似文献   

20.
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