Researchers have made GPS accurate to within a centimetre

“To fulfil both the automation and safety needs of driverless cars, some applications need to know not only which lane a car is in, but also where it is in that lane – and need to know it continuously at high rates and high bandwidth for the duration of the trip,” said lead research Jay Farrell, from the University of California, Riverside…
Farrell and his team developed a new technique that supplements existing GPS data with on-board inertial measurements from a sensor. The merging of those measurements in itself isn’t new, but in the past it’s required super-expensive computers to combine the two data sources, which meant it was never going to work in your car or smartphone, regardless of how accurate it was.