Seems you've missed the news Check_Thrust. The prediction has near come true.
Flying Binghi,
I never said that terrorist groups can't or wouldn't use GNSS to their own means, it is quite a logical conclusion that they would try, just as groups have utilised mobile phone technology to detonate explosive devices, but are you suggesting that the world should shutdown every mobile phone network as well?
To note as well, I did not bring up the topic about 'Bingy's Buzz Bombs' nor did I criticise your previous opinions on the possibility that they may be made or used. I do not believe though that they would be used extensively enough to warrant a full scale implementation of Selective Availability or even for the system to be turned off (but who knows, I may be be proved wrong in the future as the future is a long stretch of time).
At the present point in time there are two fully functional worldwide GNSS networks, GPS (USA) and GLONASS (Russia). By 2020 it is expected that in addition to GPS and GLONASS that there will be additional two worldwide navigation systems, Compass (China) and Galileo (EU). It is expected that in the future GNSS devices will be able to utilise signals from multiple satellite networks to derive a position, not just the GPS network. It is already happening with the Garmin GLO as one example that can utilise both GPS and GLONASS to derive a position fix. (I have seen it stated that some believe that Garmin have only done this to avoid Russian tariffs that are imposed on GNSS products that do not utilise the GLONASS network, and I don't blame Russia for imposing such tariffs given the obvious cost behind setting up GLONASS, but it at the end of it all one would expect that future GNSS units will use all available networks for their own benefit and reliability).
Now, come 2020 with four fully functional GNSS networks, run by four different governments it is unlikely (note I have said unlikely, not won't) that a situation would occur that would result in any or all of the networks to be either switched off or have Selective Availability imposed. What benefit would doing either have? If any major country was to cause aggression with another, there would be no benefit in making their network unavailable to the other because the opposing side will have their own network to utilise anyway.
Quote:
via Check_Thrust #56:
...I think we will have other things on our mind apart from ADS-B not working."
You've obviously given the matter much thought and research, please do enlighten us
Check_Thrust...
I think you already know the logic behind my comment but since you have asked I will provide it anyway.
If there is enough aggression towards a nation that controls a GNSS network that then results in that nation to either turn off their network or to impose Selective Availability do you not think that the first thing on your mind would be, "Heck, the world is in a seriously screwed situation if there is going to be a war" and "although I can't do anything to stop it, how will this affect me and my family".
Now apart from that dramatised scenario above, if GNSS was switched off, we would not be the only industry affected by it. Marine, rail (believe it or not), road transport (not talking Joe Blogs that uses his car satnav to go to the corner shop), mining and law enforcement agencies (and no doubt many other groups as well) across the globe would all be affected. Although these industries have operated in the past without GNSS and they can do so again if need be, it would obviously be a large inconvenience for it to happen and not necessarily in a governing states best interest for it to happen.
CDMA phone networks (although no longer used in Australia there are still over 50 countries including the USA that have and utilise CDMA networks) rely on the timing provided (not position fixing) by the GPS network in regards to how it encodes, sends and decodes telephone transmissions, so if GPS was turned off it would have major effects on telecommunications as well. (If you were one of the many Australians that owned a CDMA phone did you live in fear that your phone call would cut out and your phone rendered useless if the US decided to make GPS unavailable?)
In addition to all this from an aviation perspective for the USA alone there are over 3000 LPV approaches of which over 1500 serve airports without an ILS, so again, if the USA was to tinker with their GPS network it would have big effects on themselves as well.
Again, I will restate that although it is possible that each GNSS network could be tinkered with to prevent civilian use of the systems but I believe that it is extremely unlikely that it would happen given all the implications that would occur. Also given that there will be four networks available, for something to happen that would affect all four networks it would have to be a very major global event (and yes, I am aware that there have been major worldwide confrontations before), however with each major government power having their own network it wouldn't really provide a strategic advantage to make their own network unavailable (I know I am repeating this point).
So to say that Australia and other nations (including the US, although not mandatory until 2020) should not implement the use of ADS-B on the bases of "What happens to ADS-B when the civy GPS gets turned off
?" is in my opinion, silly (and you are entitled to your own opinion that conflicts with mine). If ADS-B was to fail due to the GPS network being turned off in current times, or multiple GNSS networks being turned off in future times, air traffic controllers the world over will still be able to revert to procedural based separation where there is no SSR coverage (although I am sure it would cause many headaches in areas of crowded airspace). To prevent making air transport easier and more efficient for everyone involved on the bases of what might happen due to a very remote possibility is again just silly.