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The UK-based company is currently working with defence industry giant BAE Systems to further investigate the potential that mobile phone networks offer in terms of their ability to track objects. This concept of cell phone radar, dubbed Celldar, could provide a "totally covert and innovative approach to the detection of moving air, land and sea-based objects," Roke Manor said.
All types of radar detect objects by discharging radio waves, some of which are reflected to a receiver, which after analysis reveals the distance, speed and sometimes the size of objects. Celldar adheres to these basic principles.
But Celldar, unlike most common types of radar, is a multi-static radar system, which means that the transmission device (mobile phone base stations) and the receiving device are not in the same location. "In its simplest form, the advantage of Celldar is that you don't have to transmit from a single location," explained Celldar Program Manager Peter Lloyd. "A lot of people, in wartime, go to great lengths to blow up mono-static radar stations."
Roke's work in the area is not the first use of multi-static radar. Indeed a multi-static radar was used in the defence of Britain during World War II utilising the BBC's broadcast network. And in the US, Lockheed Martin developed a radar system in the late 1990's called Silent Sentry, which uses television and FM radio signals to detect objects. Celldar is the first use of mobile phone networks as a radar system, Lloyd said.
The covert nature of these systems is surely a bonus, but the cost of such a system is equally appealing. Since most of Europe is already covered with mobile phone transmitters, the bulk of the cost of roll out has been completed. In a test of the technology developed by Roke, the company attached two mobile phones, which acted as receivers, to a computer with 200KHz A to D converters to digitise signals from the phones.
The parts cost a mere STG2,000, Lloyd said, and the system was able to detect vehicles through foliage at a range of several hundred meters as well as people moving in a parking lot. Lloyd declined to say what the operational range of Celldar is, nor would give details about its accuracy, but he did say that "any aircraft flying anywhere over a continent would be detectable."
For now BAE and Roke have signed an agreement to fund the development of the technology. But after more research and development is complete, Lloyd envisions more than just military applications for the technology that the firms claim is sophisticated enough to detect small maritime objects, such as periscopes, and even aircraft that use stealth technology. Police forces and security personnel could also use the technology to monitor ground sites and the system could potentially be utilised for commercial aircraft detection, Lloyd said.
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