Stewart Penney/LONDON
Roke Manor, the UK research and development consultancy, is pursuing a method of detecting stealth aircraft using mobile telephone base station transmissions, and a development of commercial air traffic control equipment.
Peter Lloyd, Roke Manor project manager, says coded signals transmitted by the base stations would be scattered by passing aircraft. A modified version of the company's civil Height Monitoring Element (HME) civil equipment would detect these signals. A number of returns would then triangulate the target's position.
He says the system would act as a bistatic radar. Base stations continually transmit coded signals to allow the mobile phone network to operate and, says Lloyd, do not need modification to become part of a counterstealth radar.
Lloyd says Roke Manor's signals processing technology will allow the modified HME to detect aircraft returns. He adds that the HME's front end requires modification to reflect the non-co-operative nature of the target. HME measures a commercial aircraft's secondary surveillance radar transponder data and is in service with Eurocontrol and across the North Atlantic to monitor compliance with Reduced Vertical Separation Minima.
One difficulty is synchronising the receiver sites, says Lloyd. A solution is already incorporated in HME, which uses the GPS-satellite navigation time signal. Lloyd says HME can synchronise the stations to around 100pS.
As the detection system is similar to HME and the base stations already exist, Lloyd says an operational system is close to reality. The detection system is small enough for a mobile unit to be developed.
Lloyd says the US proposed a similar system using television transmissions. However, TV networks do not require large numbers of transmitters and can be easily targeted. Third generation mobile phone systems will provide thousands of transmitters.
Source: Flight International
