Britain Could Switch Off Airport Radar and Release 5G Spectrum 175
judgecorp writes "Britain is considering switching off air traffic control radar systems and using "passive radar" instead. A two year feasibility study will consider using a network of ground stations which monitor broadcast TV signals and measure echoes from aircraft to determine their location and velocity. The system is not a new idea — early radar experiments used BBC shortwave transmitters as a signal source before antenna technology produced a transceiver suitable for radar — but could now be better than conventional radar thanks to new antenna designs and signal processing techniques. It will also save money and energy by eliminating transmitters — and release spectrum for 5G services."
Good idea (Score:5, Informative)
It works for detecting stealth fighters over Iran, it should certainly work for non-stealth commercial aircraft.
Re:Infomercial Airlines (Score:4, Informative)
To everyone thinking that safety will depend on the TV transmitters being always on, this is likely to replace only *one* of the types of radar, primary radar (where you send out a signal and look for reflections). SSR (secondary surveillance radar) won't be going away. This type of radar sends out a signal and the aircraft actively replies.
Primary radar is used to paint targets that don't have transponders. What the CAA has been angling to do for a while now is make Mode-S transponders mandatory in controlled airspace (they did want everything, including hang gliders(!) to carry a Mode-S transponder at one point). Therefore the cost will just be transferred to the hand-to-mouth sector of aviation if they want to still have access to controlled airspace.
Re:What Could Possibly Go Wrong? (Score:2, Informative)
BA 5390 didn't need radar to guide it down. No maps got sucked out.
Re:Government control of private transmitters? (Score:5, Informative)
All of the BBC's transmitters were sold off to a private company years ago as part of the Broadcasting Act 1990.
Re:What Could Possibly Go Wrong? (Score:4, Informative)
Airliners can detect other aircraft. I believe there was an incident where an airliner's collision detection radar atually detected an F117 and had to temporarily abort a climb, due to a near miss.
The Traffic Collision Avoidance System uses transponders of a particular type: they communicate with one another to determine mutual range (from round-trip signal times), azimuth (by using directional antennas) and altitude (as reported by the transponders). TCAS is mandatory for all but small airliners in most of the world, and the military use it when they are not in combat.
http://www.ll.mit.edu/publications/journal/pdf/vol02_no3/2.3.7.TCAS.pdf [mit.edu]
Re:Already at 5G? (Score:4, Informative)
Not even remotely accurate. 1G to 2G was a transition from analogue to digital cellular. You still only had a basic WAP modem function at best, and were charged per minute. At this point I had 56kbps dial up at home.
It wasn't until GPRS was added to that we even had a dedicated data channel and that was limited to sub-dial-up speeds, on a good day, but at least you were charged for the data you used and not how long your phone was online, so you could have an always-active data connection. At this point I had 512kbps broadband.
3G took that up to about 300kbps at launch - at least a tenfold improvement - and went as high as 2Mbps, before the arrival of HSDPA and related technologies that can get you up to about 50Mbps on the same spectrum. My phone was now as fast as - and often faster than - my home broadband.
1G - 0
2G - 0.05 - 0.1
3G - 0.5 - 50
4G - 50 - ?
Doesn't look like decreasing returns to me.
Re:Good idea (Score:2, Informative)
The Stealth Fighter (F117) is getting to be fairly old technology these days - after all it has been in operational use for over 23 years.