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Square Kilometer Array Radio Telescope Proposed

September 09, 2004

Discovering a new star, planet, or galaxy in our vast universe may become a more common occurrence in the next decade thanks to a radical new approach to the design of radio telescopes. Seven international teams of astronomers and engineers are each developing concepts for “Square Kilometer Array” (SKA), a massive telescope capable of receiving even the faintest signals, which will hopefully make the process of probing deeper into space an easier task. If fully constructed, the SKA would be one of the most powerful radio telescopes ever built. One of these teams, Dominion Radio Astronomical Observatory (DRAO), is proposing an innovative large adaptive reflector (LAR) design, which will use giant ground-based reflectors and balloon-mounted antenna feeds. To ensure that the balloons (or aerostats) are precisely positioned, the DRAO team turned to the C100 compass engine from KVH Industries (Nasdaq: KVHI).

The SKA design proposed by DRAO will consist of an array of 32 individual antenna stations, which will produce an aperture with a diameter of several thousand kilometers. Each antenna station will consist of a giant reflector composed of 1,500 triangular panels to accept incoming radio waves. Floating above each reflector will be a tethered, helium-filled aerostat, beneath which will be suspended an antenna feed. The antenna feed will be precisely positioned using six tethers attached to computer-controlled winches on the ground. The antenna feeds will collect the deep space radio signals as they are redirected by the reflectors on the ground. The signals from all 32 reflectors will then be combined to provide a unique look at the universe.

Both the aerostat and the antenna feed will have to be precisely positioned for this to work properly. To maintain the necessary precision positioning, the DRAO team is using GPS, tilt sensors, and an inertial measurement unit along with KVH C100 compasses to monitor and control the entire system. One C100 compass is mounted on the aerostat to record its heading. The other C100 is mounted on the receiver/feed platform along with an ultrasonic wind speed and direction sensor, allowing the computers to record platform orientation and wind direction. Together, these components provide a precise picture of the antenna array’s position in 3-D space and enable the computer-controlled winches to make the adjustments necessary to keep the aerostat and antenna feed within 1 centimeter of their target position at all times.

“The C100 has met our requirements very well, not only providing us with reliable data but also proving to be very robust in surviving the rough environment of our field testing,” said Dean Chalmers, mechanical engineer at DRAO. “The main reason we chose the C100 is that it has both analog and RS232 output. We need analog since that was what we planned on using, but wanted the option to transition to digital in the future.”

The KVH C100 compass engine is a stand-alone sensor subsystem that outputs extremely accurate heading data in six user selectable digital or analog formats. Compact and affordable, the C100 was designed with flexibility in mind, making it simple to integrate into any system. Additional details regarding the C100 compass engine are available at www.kvh.com/digicomp.

Testing for the prototype will continue this fall and final proposals for the SKA telescope are due in 2007. Selection of the final design of the SKA telescope will take place in 2008 and final construction is expected to begin in 2012. More information on DRAO and its approach to the SKA challenge is available at www.drao-ofr.hia-iha.nrc-cnrc.gc.ca/science/ska/.

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