Roke Manor Research, part of Siemens Corp., has demonstrated a passive radar that exploits signals from GSM mobile phone base stations.
"Base station signals go further than you think--several kilometers. We could develop a ground-based sensor for aircraft or an aircraft-mounted sensor," said Program Manager Peter Lloyd. "Base stations cover almost all of the British coast, so Celldar could be used to detect boats or periscopes offshore."
Celldar, its name derived from "cell phone radar" is completely covert, and systems could be built for a fraction of the cost of conventional military radar, Lloyd said.
Roke Manor's technology demonstrator uses two conventional Yagi aerials, two mobile phones as receivers and a PC with 200KHz A to D converters to digitize signals from the phones.
The parts cost $3,076 (2,000 British pounds), according to Lloyd, and this simple set-up can detect vehicles through foliage at a range of several hundred meters as well as people moving in a parking lot. To locate an object on the ground, two base stations would be needed, or three to locate a flying object.
"The more the merrier," Lloyd said. "There are plenty in Britain; it is likely to be 10 or more."
BAE Systems just signed up to fund the project with cash and additional know-how.
Eventually Celldar will use phased array antennas, a technology that Roke Manor specializes in. Each of the hundred-or-so antenna elements will have a separate receiver and ADC, all feeding some form of processor. "A phased array radar for less than $150,000 (100,000 pounds)," Lloyd said.
Cross-correlation of direct and reflected signals is the method being used to detect time differences in the development system. Roke Manor hopes to add mobile phone knowledge from parent company Siemens to extract more information, but Lloyd is reluctant to say exactly what.
Range and accuracy are also not being discussed, although Lloyd did tell Electronics Weekly that Roke Manor has a height-measuring system that works at similar frequencies and is accurate to about 10 meters.
The result of cooperation with BAE Systems should be a phased array multimode Celldar demonstrator within two years, Lloyd said.
The MoD is also putting in cash through its Radar Tower of Excellence program and Louisiana State University. A specialist in aviation is also involved, Lloyd said.
Roke Manor and BAE Systems have previously collaborated on the development of Sampson phased array, multifunction radar, which has been selected for the Type 45 destroyers and HALO artillery location system now in service with the British Army.
Steve Bush is an editor at Electronics Weekly, a sister publication to Electronic News.
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