Cruising across the wilds of central Nevada the other day, my thoughts turned to GPS and the frequent outage NOTAMs we get when the military decides to play games with the signals. Its not uncommon for wide swaths of the western deserts to have warnings that GPS might be unreliable for significant portions of time. Now don't get me wrong - I am the very understanding of the potential military issues of having or not having GPS available (by the military and everybody else), as well as the need to train for use without it. We have to remember that initially, GPS was designed as a military asset - the fact that it has now been incorporated as key technology in everything more advanced than a toaster is simply a testament to its universal acceptance.
I am also a fan of the concept of NextGen - the ultimate air traffic control system that is the end goal of all this ADS-B work we're doing. Basically everything in the air puts out its position so everyone else knows it is there, and you do away with all of the ground radars. Elegant, fast, works without a wide distribution of ground equipment of different vintages and pedigrees. But getting there is tricky, That is a whole lot of change that has to occur.
And one of those changes is that if everyone from us lowly GA pilots up through the airlines and military is dependent on GPS to keep traffic separated, then you absolutely, positively can not let that signal go away - not with tens of thousands of unsuspecting commercial passengers unknowingly depending on it to prevent a reoccurrence of the bad old days of the early 1950s, when several airliners collided before the age of modern air traffic control.
What really has me thinking about this is that nowhere am I seeing a hue and cry from people who recognize this as a problem. I have yet to read a single article that says that the military has promised not to do this spoofing starting in 2020. But if they really did pull out all the radars (won't happen), and the airliners all equip (they aren't going to be anywhere near close to being equipped by 2020), then the only way to separate traffic with all those blissfully ignorant general public travelers on board will be by GPS. Why aren't we all talking about this?! It would scare the crap out of the average passenger (who worries about fan disks coming apart) if they knew about it.
I am not really into conspiracy theories, but don't you think the airlines will be happy when half the GA fleet is grounded, and they haven't had to spend any money on equipping because they have a deferral? Is there any real intent to make GPS the sole source of traffic separation in anything like the early 2020s?
Now I'll be honest, I really like having traffic and weather in the cockpit. I have gotten weather through satellite for years, but it is nice to have it free. But the ATC part of the system is just flat broken unless EVERYONE is playing, including the military - and they don't appear to be. I'd love to have NextGen completely up and running - but there are key blocks that aren't being put in place to keep it from falling down.
Fortunately, the other day, no one was playing games, and the IFR navigator that feeds my ADS-B, along with the three VFR GPS receivers in my EFIS, the GPS in my iPad, and the extra receiver in my iPhone all kept tracking and telling me that yes indeed, I really did have a headwind that was going to make me late and put me in the height of the afternoon bumps across the mountains. But that's another story.