It's called differential GPS. However the new block of GPS sats have higher accuracy without the need for the (multiple) expensive receivers. However, I'd argu

It's called differential GPS. However the new block of GPS sats have higher accuracy without the need for the (multiple) expensive receivers. However, I'd argue the lanekeeping and "where am I" problems this stuff solves is dwarfed by the common sense and logical reasoning & recognition problems.