用户:ChenKB91/深空网络

坐标：34°12′3″N 118°10′18″W / 34.20083°N 118.17167°W / 34.20083; -118.17167
维基百科，自由的百科全书
深空网络
1988年NASA深空网络成立40周年纪念图章
组织NASA / JPL
座标34°12′3″N 118°10′18″W / 34.20083°N 118.17167°W / 34.20083; -118.17167
设立1958年十月一日
网址deepspace.jpl.nasa.gov
望远镜
金石深空联络设施
美国加州巴尔斯多
马德里深空联络设施
西班牙马德里自治区罗夫来多-德查韦拉
堪培拉深空联络设施
澳大利亚提德宾比拉自然保留区

美国国家航空航天局深空网络（英语：Deep Space Network）是NASA设置的一个用以联络航天器的全球网络设施，位于美国(加洲)、西班牙(马德里)和澳大利亚（堪培拉），用以为美国国家航空航天局的行星际航行太空船提供通讯，也被用来执行射电天文学和雷达天文学对于太阳系和宇宙的观测，并对地球轨道上的人造卫星提供支持，是NASA喷射推进实验室 （JPL）的一部分。欧洲、俄罗斯、中国、印度和日本也有类似的网络。

一般资讯[编辑]

喷射推进实验室内部的深空网络运作中心

DSN目前包含三个深空通信设施，以约120度的间隔围绕着地球。[1]分别为：

每个设施皆位于半山腰、碗状地形，以帮助阻挡无线电波干扰。[2] 考虑到地球的自转，三座设施的地点以约120度的间距为绕着地球，目的是为了当地球自转时，一座设施转到背对着目标的一侧，而无法进行观测，但同时另一座设施便转到了可进行观测的一侧，如此DSN便能24小时持续观测目标。

NASA倚赖DSN以进行太阳系内的科学调查：可以双向沟通，地面基地可以引导并控制各种NASA的太空探测器，让这些探测器可以传回他们所收集的照片和数据资料。所有DSN天线皆具备高增益、附带抛物面反射器的天线。这些天线盒数据传送系统，使其能够：

  • 自航天器获得遥测数据。
  • 向航天器发送指令。
  • 更新修改航天器内建软体。
  • 追踪航天器的位置和速度。
  • 执行特长基线干涉测量。
  • 测量无线电波的变化，以进行无线电波科学实验。
  • 收集科学数据。
  • 监测和控制整个系统的性能。

控制中心[编辑]

三座DSN设施的天线都直接连结到加州帕萨迪纳喷射推进实验室内部的深空控制中心（也称为深空网络操作控制中心）。

在早期，控制中心内并没有所谓的永久设施，只有一个临时搭建的，以好几张桌子与和电话拼装在一个大房间电脑旁边，以用来计算轨道。1961年七月，NASA开始建造永久设施：太空飞行操作设施（SFOF）。 该设施于1964年十月建造完成，并于1964年5月14日启用。 一开始共有31座主控台，100个闭路电视摄像机和200多台显示器，用以支持游骑兵6号到9号，以及水手4号任务。[3]

目前，控制中心的工作人员在SFOF内监测并主导行动，并监侧探测器的通讯品质，并掌管资料以提供给提供给通讯网络的使用者。此外，DSN的各个设施和操作中心，设有地面通讯设施，将三座设施的资料传送给JPL的控制中心，再传到世界各国的太空飞行控制中心，以及世界各地的科学家。

深空的定义[编辑]

从北极点上空向下看的示意图，显示DSN观测站的位置及视角。当一台探测器距离地球超过30,000公里，它便随时处于一个以上探测站的视野之中，并与之建立联系。

追踪太空深处的探测器相当不同于追踪低地球轨道上的探测器。深空飞行任务通常可见于大部分地球表面，并且可持续很长一段时间，因此只需要很少观测站便可达成长时间追踪的目的（DSN只有三个主要观测站）。然而，由于这些探测器距离地球相当遥远，这些观测站则需要巨大的天线、非常灵敏的接收器，以及强大的讯号发射器，才能与探测器联系。

深空有数种不同的定义。根据一份1975年NASA的报告，DSN是设计来与“距离地球16000公里以上到太阳系中最远的行星之间” 建立通讯[4]。JPL声明，当一探测船位于距离地球30,000公里以上的高度，该探测船便总是位于至少一个观测站的视野之内。[5]

国际电信联盟保留了数个频段，提供给深空网络及近地空间作通讯使用，他们定义：“深空”是指距离地球两百万公里以上的空间。

这个定义代表着月球任务，以及地球-太阳拉格朗日点的L1 和L2，都被认为是近地空间，不能使用国际电联的深空保留频段。其他的拉格朗日点则不受到这条规则限制。

管理[编辑]

深空网络所属于NASA，由JPL对其进行管理和运行，而后者是加州理工学院的一部分。行星际网络理事会（IND）由JPL的研究开发及运作所支撑，并管理JPL的内部计划。The IND is considered to be JPL's focal point for all matters relating to telecommunications, interplanetary navigation, information systems, information technology, computing, software engineering, and other relevant technologies. While the IND is best known for its duties relating to the Deep Space Network, the organization also maintains the JPL Advanced Multi-Mission Operations System (AMMOS) and JPL's Institutional Computing and Information Services (ICIS).[6][7]

Harris Corporation is under a 5-year contract to JPL for the DSN's operations and maintenance. Harris has responsibility for managing the Goldstone complex, operating the DSOC, and for DSN operations, mission planning, operations engineering, and logistics.[8][9]

天线[编辑]

70 m antenna at Goldstone, California.

每座设施都包括至少四座深空终端机，装载高敏感讯号接收器，以及大抛物面发射天线。他们分别为：

  • 一座直径34米（112英尺）的高功效发射天线(HEF)
  • 两座以上的34米（112英尺）波导天线（英语：Beam waveguide antennas）（哥德斯通有三座运行中，马德里有两座，堪培拉设有三座。）
  • 一座直径26米（85英尺）发射天线
  • 一座直径70米（230英尺）发射天线

Five of the 34-米（112-英尺） beam waveguide antennas were added to the system in the late 1990s. Three were located at Goldstone, and one each at Canberra and Madrid. A second 34-米（112-英尺） beam waveguide antenna (the network's sixth) was completed at the Madrid complex in 2004.

一般能力的DSN没有基本改变，因为一开始的星际旅行者的任务在1990年代初期。 然而，许多进步数字信号处理、排列和错误的修正已经通过的DSN。

The ability to array several antennas was incorporated to improve the data returned from the Voyager 2 Neptune encounter, and extensively used for the Galileo spacecraft, when the high-gain antenna did not deploy correctly.[10]

The DSN array currently available since the Galileo mission can link the 70-米（230-英尺） dish antenna at the Deep Space Network complex in Goldstone, California, with an identical antenna located in Australia, in addition to two 34-米（112-英尺） antennas at the Canberra complex. The California and Australia sites were used concurrently to pick up communications with Galileo.

Arraying of antennas within the three DSN locations is also used. For example, a 70-米（230-英尺） dish antenna can be arrayed with a 34-meter dish. For especially vital missions, like Voyager 2, the Canberra 70-米（230-英尺） dish can be arrayed with the Parkes Radio Telescope in Australia; and the Goldstone 70-meter dish can be arrayed with the Very Large Array of antennas in New Mexico. Also, two or more 34-米（112-英尺） dishes at one DSN location are commonly arrayed together.

All the stations are remotely operated from a centralized Signal Processing Center at each complex. These Centers house the electronic subsystems that point and control the antennas, receive and process the telemetry data, transmit commands, and generate the spacecraft navigation data. Once the data is processed at the complexes, it is transmitted to JPL for further processing and for distribution to science teams over a modern communications network.

Network limitations and challenges[编辑]

70m antenna in Robledo de Chavela, Community of Madrid, Spain

There are a number of limitations to the current DSN, and a number of challenges going forward.

  • The Deep Space Network is something of a misnomer, as there are no current plans, nor future plans, for exclusive communication satellites anywhere in space to handle multiparty, multi-mission use. All the transmitting and receiving equipment are Earth-based. Therefore, data transmission rates from/to any and all spacecrafts and space probes are severely constrained due to the distances from Earth.
  • The need to support "legacy" missions that have remained operational beyond their original lifetimes but are still returning scientific data. Programs such as Voyager have been operating long past their original mission termination date. They also need some of the largest antennas.
  • Replacing major components can cause problems as it can leave an antenna out of service for months at a time.
  • The older 70M & HEF antennas are reaching the end of their lives. At some point these will need to be replaced. The leading candidate for 70M replacement had been an array of smaller dishes,[11][12] but more recently the decision was taken to expand the provision of 34-meter (112 ft) BWG antennas at each complex to a total of 4.[13]
  • New spacecraft intended for missions beyond geocentric orbits are being equipped to use the beacon mode service, which allows such missions to operate without the DSN most of the time.

DSN and radio science[编辑]

Illustration of Juno and Jupiter. Juno is in a polar orbit that takes it close to Jupiter as it passes from north to south, getting a view of both poles. During the GS experiment it must point its antenna at the Deep Space Network on Earth to pick up a special signal sent from DSN.

The DSN forms one portion of the radio sciences experiment included on most deep space missions, where radio links between spacecraft and Earth are used to investigate planetary science, space physics and fundamental physics. The experiments include radio occultations, gravity field determination and celestial mechanics, bistatic scattering, doppler wind experiments, solar corona characterization, and tests of fundamental physics.[14]

For example, the Deep Space Network forms one component of the gravity science experiment on Juno. This includes special communication hardware on Juno and uses its communication system.[15] The DSN radiates a Ka-band uplink, which is picked up by Juno's Ka-Band communication system and then processed by a special communication box called KaTS, and then this new signal is sent back the DSN.[15] This allows the velocity of the spacecraft over time to be determined with a level of precision that allows a more accurate determination of the gravity field at planet Jupiter.[15][16]

See also[编辑]

参考文献[编辑]

  1. ^ Haynes, Robert. How We Get Pictures From Space (PDF). NASA Facts Revised (Washington, D.C.: U.S. Government Printing Office). 1987 [2013-09-19]. 
  2. ^ DSN:antennas. JPL, NASA. （原始内容存档于2011-04-11）. 
  3. ^ Deep Space Network Operations Control Center at the Jet Propulsion Laboratory, Pasadena, California. Picture Album of the DEEP SPACE NETWORK. NASA/JPL. [26 January 2014]. （原始内容存档于17 February 2013）. 
  4. ^ N. Renzetti. DSN Functions and Facilities (PDF). May 1975. 
  5. ^ Dr. Les Deutsch. NASA’s Deep Space Network: Big Antennas with a Big Job (PDF).  p. 25
  6. ^ IND Technology Program Overview. JPL. 
  7. ^ Weber, William J. Interplanetary Network Directorate. JPL. May 27, 2004. hdl:2014/40704.  Missing or empty |url= (help)
  8. ^ ITT Exelis selected for NASA Deep Space Network subcontract by Jet Propulsion Laboratory (新闻稿). ITT Exelis. 23 May 2013 [5 July 2016]. 
  9. ^ Gelles, David. Harris Corporation to Buy Defense Contractor Exelis for $4.7 Billion. DealBook. [2016-10-31]. 
  10. ^ Uplink-Downlink, Chapter 5, The Galileo Era – 1986–1996.
  11. ^ The Future Deep Space Network: An Array of Many Small Antennas. JPL. （原始内容存档于July 14, 2009）. 
  12. ^ Durgadas S. Bagri; Joseph I. Statman & Mark S. Gatti. Proposed Array-Based Deep Space Network for NASA (PDF). IEEE. 
  13. ^ DSN Aperature Enhancement Project. 
  14. ^ Radio Science. JPL. 
  15. ^ 15.0 15.1 15.2 [1]
  16. ^ [2]

[[Category:噴射推進實驗室]] [[Category:射电天文学]]

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