In cars, in ships, in planes, in our phones, we'll be lost without sat nav. It's amazing - some might say alarming - just how rapidly it sent us off in a new direction, away from self-reliance towards technological dependence, which would be fine if GPS and its sister systems were all utterly dependable. But they're not, and that could have dangerous, potentially disastrous consequences. We'll get onto what those are in due course. But before we set off, it might help to get our bearings.

译文：

汽车里、轮船上、飞机上、手机中，如果没有卫星导航系统，我们就会迷失方向。它如此迅猛地将我们送往一个全新的方向，不再依靠自己，而是依赖于技术，这真是无比神奇，但也有人会说这令人警醒。如果GPS及其协同系统都完全可靠，这固然不错。但事实并非如此，而这也就可能带来危险、甚至可能是灾难性的后果。我们稍后会讨论这个。不过在此之前，先了解一些情况会有所帮助。