OSU To Build Revolutionary
New Radio Telescope
By Bob Dixon and Steve Ellingson
OSU has begun development of a revolutionary new radio telescope, known as Argus. Whereas traditional radio telescopes use large parabolic dishes to capture weak astronomical signals from a tiny section of the sky, Argus will use a planar array of antennas to observe the entire sky continuously. Argus is being designed and built at the OSU ElectroScience Laboratory (ESL) with financial support from the SETI Institute. The goals of the project are to demonstrate the use of large adaptive arrays for radio astronomy and the scientific Search for Extraterrestrial Intelligence (SETI). Both disciplines need radio telescopes which can observe the entire sky continuously, in order to more easily detect transient events. Also, array technology makes it easier to observe in the presence of man-made radio frequency interference (RFI), which currently plagues radio astronomy and threatens to close off Man's ability to observe the universe at radio frequencies. Array systems such as Argus are being developed to satisfy these requirements in a way that conventional dish antennas never will.
Argus will be constructed at the ESL facility on Kinnear Road, and is expected to be completed in mid-2000. It will consist of 64 omnidirectional antennas forming a planar array. The tuning range of the system will be 200 MHz to 2 GHz, with an instantaneous bandwidth of 1.5 MHz. The signal from each antenna will be downconverted in frequency and digitized. The digitized signals will then be processed to remove RFI, and then will be used to form a map of the sky at radio frequencies. Thus, within a few seconds, Argus will be able to complete a survey of the sky that would normally take months to complete with a traditional radio telescope. A major challenge in developing Argus is mustering the tremendous computational power required to operate the system. This problem is so difficult, in fact, that Argus will initially be no more sensitive than a small home satellite dish. Nevertheless, advanced signal processing techniques will allow it to resolve key astronomical features such as Cassiopeia A (a prominent supernova remnant), Sagittarius A (the black hole at center of our galaxy), and measure the redshift of galactic hydrogen, which signals the shape and motion of our galaxy. Thus, Argus will be an important proof-of-concept for array-based radio astronomy.
The OSU Argus project is just one facet of an international effort to build the supreme radio astronomical instrument of all time: the Square Kilometer Array (SKA). SKA's name refers to it's total collecting area (effective aperture) - one square kilometer - making it the world's most sensitive radio telescope by at least two orders of magnitude. SKA is envisioned as the means to answer some of the most difficult and important questions in modern science, such as the nature of the early (high redshift) universe, the detection of gravity waves, and possibility of life outside our solar system. In addition to OSU and the SETI Institute, key institutions involved in SKA include MIT, U.C. Berkeley, Colorado State, and the national radio observatories of Australia, Canada, and the Netherlands. It is believed that SKA can be built sometime between 2005 and 2015. Argus is one of three systems currently being developed as precursors to SKA. The others are the One-Hectare Array (1hT), an array of small dishes being built by U.C. Berkeley at the Hat Creek Radio Observatory site in California; and the Thousand Element Array (THEA), being built at the Netherlands national facility at Dwingeloo. These projects were conceived to test various concepts and design options for SKA, and a close collaboration exists among project teams.
OSU has a rich history of contributions to Radio Astronomy and SETI, primarily through the activities at OSU's ``Big Ear'' Radio Telescope, built in the early 1960's by the legendary OSU radio astronomer, physicist, and engineer John Kraus and his students. OSU suffered a tremendous loss of prestige in the radio astronomy community with the demolition of Big Ear in 1997 to make way for the expansion of a nearby golf course. The kickoff of the Argus project represents OSU's reentry into this community. It is being financed completely by grants from private organizations, with no funding from the university, or local, state, or federal governments. Nevertheless, Argus will be a tremendous boon to OSU, giving researchers and students the opportunity to develop advanced technology that is currently in high demand in the commercial and government sectors. Key technology areas include antennas and antenna arrays, ultra-wideband RF systems, wideband digital receivers, high-speed parallelized digital signal processing, and RFI detection, monitoring, and suppression techniques.
For more information, contact Bob Dixon of the OSU Radio Observatory or Steve Ellingson of ESL.