TV signals could be used to locate aircraft as 5G plans take shape
February 13, 2013
Spectrum for 5G mobile networks could be freed up if a radical new system for air traffic control is approved.
Radar provider Thales
has been given government funding by the Technology Strategy Board to
investigate how existing TV signals could be used to locate and track
aircraft – using a system called “multi-static primary surveillance
radar”, or “passive radar“. The study also involves the UK’s air traffic control provider NATS and research organisation Roke Manor.
The government likes passive radar as it would allow it to sell off
the spectrum currently used by air traffic control, while Thales argues
that it would be much more reliable than the existing method, which has
been in place since the Second World War.
5G plans underway
“This
two year project will be a feasibility study which will set up
prototype systems that will use TV signals already being broadcast from
transmitters around the UK,” said a Thales spokesman. “Absolutely no
radar systems will be switched off during the study, which will report
to regulators and the air transport industry.”
The proposed system would use a new set of receivers to monitor TV
signals, as well as their reflections from objects such as aircraft. In
essence the system uses the phenomenon whereby passing aircraft can
produce “ghost” interference on older TVs, but turns it to good use by
detecting and measuring it more accurately.
By measuring the timing of TV signals reflected from aircraft, the
system will be able to locate them precisely, and measuring the Doppler
shift of the signal would also allow their speed and direction to be
measured. Such systems are called “bistatic” or “multistatic” because
they use different stations to send and receive the signals.
The principle is not new – passive radar was the basis of the very
first experiments that led up to the invention of radar during the World
War II. Robert Watson-Watt’s first demonstration of the principle of
radar in 1935 used the BBC shortwave transmitter at Daventry to detect
a Handley Page Heyford bomber at a distance of 12 km. Radar systems
moved to conventional radar enabled by antennas which could alternate
between transmit and receive.
The multistatic technique has had a renaissance recently, with the
arrival of powerful signal processing technology, and cheap directional
antennas, which has allowed systems that are as good as conventional
radar.
Thales argues that passive radar is actually more efficient than the
current system which relies on one radar transmitter per airport putting
enough signals in the sky, and which can be susceptible to confusing
echoes and interference from the increasing number of wind farms in the
UK. However the company acknowledges that it may encounter resistance to
change and that it must convince people of the advantages and safety of
the new system.
“This system should be more cost effective, as it uses signals which
are already being transmistted,” said the Thales spokesman. “Digital TV
is part of the critical national infrastructure, so it is already
safeguarded and will be reliable.” The system will also reduce power
consumption, making a small contribution to reducing the carbon
footprint of air travel.
No cost for the project has been revealed, but the TSB is funding
half of it, with the rest coming from the commercial partners Thales,
NATS and Roke Manor Research.
“The funding that we have secured today from the Technology Strategy
Board is a significant endorsement of the potential long-term benefits
of this research,” said Marion Broughton, head of Thales UK’s aerospace
business. “Although in its infancy, this innovative application of new
technology could reshape the way that air traffic is managed in the
future. This is a good example of how Government and industry can work
together, share expertise, and sustain innovation and high-technology
research within the UK”.
EE is currently the UK’s only 4G operator
but Ofcom has already started to plan for the next next-generation of
mobile networks. It has identified spectrum in the 700MHz bandwidth used
for digital terrestrial television that could be freed up in time for
2018 and used for 5G services.
Last year, TechWeekEurope revealed a trial of 5G services is set to go ahead in the UK in 2013, which should offer users speeds of up to 200Mbps. That will be delivered by the £35 million 5G Innovation Centre, based at the University of Surrey.
Peter Judge contributed to this story.
0 comments:
Post a Comment