I think the future will rather be based on onboard-systems like ADS-B. Terrestrial TV transmissions are a thing of the past (there are broadband cables in urban regions and satellite TV everywhere else) and they should rather free the part of the EM-spectrum that is currenty occupied by TV rather than that assigned to air traffic control.
IMHO this is a joke.
The chance of a risk analysis (TV transmitter downtime, etc) on this getting through NATS is zero. They even do a risk analysis on a potted plant.
Technically, it appears to work.
I dont know enough about this technically (though I did begin to study it once, and gave up to do business management instead (how exciting)), but I just wouldnt feel comfortable knowing I or other aircraft are being tracked based on TV signals. I know Radar is no new technology but you generally know it works. TV aerials / transmitters, give me the confidence I would have in an NDB, though I accept that is probably technically unfounded, but thats just how I feel.
On the other hand, this development would provide the UK with a radar system capable of tracking stealth aircraft, and which would probably be more robust than the present system which has large gaps in its coverage at low-level. It sounds as if it should be quite fault-tolerant so it may not matter too much if a few transmitters go down. Even if the civil aviation authorities aren't keen, I imagine that the RAF might push for such a system and this might smooth out (or perhaps bulldozer) any natural reluctance to change.
It wouldn't be without precedent - Radio 4 long-wave apparently provides a timing reference that was used - and may still be used - for military navigation - and this may be the only reason the station is still broadcasting on this frequency. I imagine terrestrial broadcasting has some life in it yet - it'll be a while before they turn off radio, and the digital channels are broadcast on the same frequencies as the television signals.
