Preventing Mid-Air Collisions
I'm not too sure if I should post this because of recent tragic events, but perhaps now might be a good time to discuss it.
All the technology is there to make mid-air collisions a thing of the past but because of bureaucracy, the solution to this problem is years away.
Let's look at what's required to implement ADS-B for light aviation:-
1) A way of broadcasting information via radio - just a few miles should do, but a bit more would perhaps be useful. This is pretty straightforward especially if a lowish frequency (100-200 MHz) were used.
2) Accurate position and time information - easily available by GPS.
3) A bit of software to control everything. Not difficult.
4) A display to give information of other traffic. Easily available.
5) Some bits of paper from the authorities that say you're allowed to switch it on. This is the difficult and expensive bit!
The hardware costs for the above will be well under £100 (especially if a PDA or some such device was used for the display), and if everyone had one then collision would reduce substantially.
Sadly, due to the bureaucracy a very low risk of electronic interference with other equipment is used to justify the high risk of doing nothing.