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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Allen Telescope Array | 4/4 | https://en.wikipedia.org/wiki/Allen_Telescope_Array | reference | science, encyclopedia | 2026-05-05T13:15:32.906338+00:00 | kb-cron |
The ATA-42 configuration will provide a maximum baseline of 300 m (and ultimately for the ATA-350, 900 m). A cooled log-periodic feed on each antenna is designed to provide a system temperature of ~45K from 1–10 GHz, with reduced sensitivity in the ranges of 0.5–1.0 GHz and 10–11.2 GHz. Four separate frequency tunings (IFs) are available to produce 4 x 672 MHz intermediate frequency bands. Two IFs support correlators for imaging; two will support SETI observing. All tunings can produce four dual polarization phased array beams which can be independently pointed within the primary beam and can be used with a variety of detectors. The ATA can therefore synthesize up to 32 phased array beams. The wide field of view of the ATA gives it an unparalleled capability for large surveys. The time required for mapping a large area to a given sensitivity is proportional to (ND)2, where N is the number of elements and D is the diameter of the dish. This leads to the surprising result that a large array of small dishes can outperform an array with a smaller number of elements but considerably greater collecting area in the task of large surveys. As a consequence, even the ATA-42 is competitive with much larger telescopes in its capability for both brightness temperature and point source surveys. For point source surveys, the ATA-42 is comparable in speed to Arecibo and the Green Bank Telescope (GBT), but three times slower than the Very Large Array (VLA). The ATA-350, on the other hand, will be one order of magnitude faster than the Very Large Array for point source surveys, and is comparable to the Expanded Very Large Array (EVLA) in survey speed. For surveys up to a specified brightness temperature sensitivity, the ATA-98 will exceed the survey speed of even the VLA-D configuration. The ATA-206 should match the brightness temperature sensitivity of Arecibo and the GBT. The ATA, however, provides better resolution than either of these single-dish telescopes. The antennas for the ATA are 6.1 x 7.0 meters (20.0 ft x 23.0 ft) hydroformed offset Gregorian telescopes, each with a 2.4 meter sub-reflector with an effective focal length/diameter (f/D) ratio of 0.65. (See DeBoer, 2001). The offset geometry eliminates blockage, which increases efficiency and decreases the side lobes. It also allows for the large sub-reflector, providing good low frequency performance. The hydroforming technology used to make these surfaces is the same as that used by Andersen Manufacturing of Idaho Falls, Idaho to generate low-cost satellite reflectors. The unique interior frame rim-supported compact mount allows excellent performance at low cost. The drive system employs a spring-loaded passive anti-backlash azimuth drive train. Most components designed by Matthew Fleming and manufactured at Minex Engineering Corp. in Antioch, CA.
== Data management == As with other arrays, the huge amount of incoming sensory information requires real-time array processing capability in order to reduce data volume for storage. For ATA-256, the average data rates and total data volume for the correlator are estimated to be 100 Mbyte/s and 15 Pbytes for the five-year survey period. Experiments such as transient surveys will exceed this rate significantly. The beamformers produce data at a much higher rate (8 gigabytes per second (Gb/s)) but only a very small fraction of this data is archived. In 2009, the signal detection hardware and software was called Prelude, which was composed of rack-mounted PCs augmented by two custom accelerator cards based on digital signal processing (DSP) and field-programmable gate array (FPGA) chips. Each Programmable Detection Module (one of 28 PCs) can analyze 2 MHz of dual-polarization input data to generate spectra with spectral resolution of 0.7 Hz and time samples of 1.4 seconds. In 2009, the array had a 40 Mbit/s internet connection, adequate for remote access and transferring of data products for ATA-256. An upgrade to 40 Gbit/s was planned, which would enable direct distribution of raw data for offsite computing.
=== Computational complexity and requirement === Like other array systems the ATA has a computational complexity and cross-connect which scales as O(N2) with the number of antennas
N
{\displaystyle N}
. The computation requirement, for example, for correlating the full ATA bandwidth (
B
{\displaystyle B}
= 11 GHz) for the proposed
N
{\displaystyle N}
= 350 dual-polarization antenna build-out, using an efficient frequency-multiply (FX) architecture and a modest 500 kHz channel width (with number of channels
F
{\displaystyle F}
= 2200), is given by:
2
B
⟨
N
log
2
(
F
)
(
10
O
P
s
)
+
(
N
N
+
1
2
)
×
4
(
8
O
P
s
)
⟩
{\displaystyle 2B\langle N\log _{2}(F)(10OPs)+(N{\frac {N+1}{2}})\times 4(8OPs)\rangle }
= 44 Peta-OPs per second where
O
p
s
{\displaystyle Ops}
is an operation. Note that since each dish has a dual polarization antenna, each signal sample is actually a two data set, hence
2
B
{\displaystyle 2B}
.
== See also ==
Carl Sagan Institute – Institute for the search of habitable worlds Exoplanet – Planet outside of the Solar System List of radio telescopes SETI Institute – Not-for-profit research organization Search for extraterrestrial intelligence – Effort to find civilizations not from Earth setiQuest Deep Synoptic Array, a more recent radio telescope also based on an array of smaller antennas
== References ==
== External links == Official website "Radio Astronomy Laboratory's ATA site". Archived from the original on 2006-09-02. Retrieved 2015-11-16. The Search Continues with the Allen Telescope Array. Mountain View, CA: SETI Institute. March 25, 2004. Radio Astronomy Laboratory, University of California, Berkeley: NSF proposal, June 15, 2005. https://web.archive.org/web/20111006031806/https://setistars.org/ Minex Engineering Corporation in Antioch, CA