[XorNot]

Or put it another way: the GPS system is used to synchronize power phases, guide aircraft, cars, people, ships. It's built into emergency transponders, military drones and bombs.

Without that system, we're back to compasses, line of sight and dead reckoning. We lose the current insane advantage of realtime positioning anywhere on the planet.

That's 1 18 satellite system - and we absolutely can't run a modern civilization without it.

[contulluipeste]

Actually, nowadays a system of ground stations and high altitudes atmospheric floating balloons can be made to serve the very same purpose. The ground stations would serve for triangulation of balloon's position and those at their turn could serve the rest of the service-consumer base. As a bonus, the balloons would be obviously more manageable compared to satellites, the cost of taking them into operation would be of course much lower (no more atmospheric pollution), and be disposed cleanly without causing the problem discussed in the article.

[chroma]

I think your estimate is overly alarmist. Without GPS, we'd use ground-based stations. It wouldn't be as accurate or as available, but it would still be good enough for almost everything GPS does. In fact, we already have ground stations to augment GPS. And even without ground-based stations, modern accelerometers allow inertial navigation to be quite accurate.

Also, GPS satellites are in medium Earth orbit, which is rather sparsely occupied. In a Kessler syndrome scenario, GPS would likely survive.