LOFAR 简介

LOFAR started as a new and innovative effort to force a breakthrough in sensitivity for astronomical observations at radio-frequencies below 250 MHz. The basic technology of radio telescopes had not changed since the 1960's: large mechanical dish antennas collect signals before a receiver detects and analyses them. Half the cost of these telescopes lies in the steel and moving  structure. A telescope 100x larger than existing instruments would therefore be unaffordable. New technology was required  to make the next step in sensitivity needed to unravel the secrets of the early universe and the physical processes in the centers of active galactic nuclei.

LOFAR的启动是一个创新性的努力, 目的是为了在低于250MHz的射电天文观测的灵敏度方面有所突破.自20世纪60年代以来,射电天文的基本技术就没怎么变过:用一个大的有机械结构的碟状天线来收集信号,然后传给接收器,然后再分析这些信号.这些望远镜一半的造价都花在了钢架和可动结构上面.因此,要造一个比现有的设备大100倍的望远镜的话谁也负担不起.为了揭示早期宇宙的秘密和活动星系核中心的物理过程,在灵敏度方面人们需要再进一步,这就需要新的技术.


LOFAR is the first telescope of this new sort, using an array of simple omni-directional antennas instead of mechanical signal processing with a dish antenna. The electronic signals from the antennas are digitised,  transported to a central digital processor, and combined in software to emulate a conventional antenna. The cost is dominated  by the cost of electronics and will follow Moore's law, becoming cheaper with time and allowing increasingly large telescopes to be built. So LOFAR is an IT-telescope. The antennas are  simple enough but there are a lot of them - 25000 in the full LOFAR design. To make radio pictures of the sky with adequate sharpness, these antennas are to be arranged in clusters that  are spread out over an area of ultimately 350 km in diameter. (In phase 1 that is currently funded 15000 antenna's and maximum baselines of 100 km will be built). Data transport requirements are in the range of many Tera-bits/sec and the processing power needed is tens of Tera-FLOPS.

LOFAR是第一个这种新型的望远镜,它采用了一个简单的全向天线阵列来代替碟状天线的机械信号处理.LOFAR从天线采集到的电信号是数字化的,它被传给中央信号处理器,通过软件叠加起来以模仿传统的天线.这种天线的主要成本是电子设备,因此遵从摩尔定律,其价钱会随着时间越来越便宜,从而允许造更大的天线.所以,LOFAR是一个IT望远镜.天线非常简单,但是数量却非常巨大--整个计划要25000个.为了在射电波段绘制天空的图像是达到足够的锐度,这些天线被安置在一个集群里,其最终覆盖范围的直径达350公里(目前一期工程已经建造了15000个天线,最长基线将达100公里). 数据传输要求达到数个T-bits每秒,而数据处理的能力则要求达到几十个T-FLOPS.

It was soon realised that LOFAR could be turned into a more generic Wide Area Sensor Network. Sensors for geophysical research and studies in precision agriculture have been incorporated in LOFAR already. Several more applications are being considered, given the increasing interest in sensor networks that “bring the environment on-line.”

人们很快就意识到了LOFAR可以放到一个更一般的大面积传感网络(Wide Area Sensor Network)里面去.用作地球物理研究和精细农业的传感器已经开始跟LOFAR合作了.人们正在考虑更多的应用,对把传感网络用作”把环境带上网”的兴趣与日俱增.

原文出自LOFAR主页:

http://www.lofar.org/p/geninfo.htm

不错不错~~~谢谢LZ的翻译~~我还是第一次听到LOFAR了~~呵呵

me too...