GPS is a godsend when it works. Problem is, there are plenty of places it doesn't work—tall skyscrapers, concrete overpasses, and other huge structures all block the satellite signal. Luckily, Swiss company u-blox devised a chip that keeps you on course when the satellites drop out, using the most old-fashioned of navigation techniques: dead reckoning.
The u-blox 3D Dead Reckoning chip uses a mix of accelerometers, gyroscopes, and speed sensors to calculate a car's exact location, no GPS signal needed. By measuring the direction, speed and distance the car has travelled since the last GPS check-in, the chip can tell if the car's still on the intended route, or if it's veered off into lost-land. U-blox's demonstration video, narrated by a charming Walter Cronkite imitator, explains in more detail:
The 3D Dead Reckoning chip isn't packed in to any currently-available GPS systems, and it's not really clear whether the company intends to sell these things to equipment manufacturers or directly to consumers—though the press release indicates it shouldn't be too hard to install yourself. [u-blox via MotorAuthority]