How Do GPS Systems Work?

They have become the must-have automotive accessory of the 2000s. Helping motorists get to their destinations without the need for a bulky map and even guiding them past traffic snarls with ease,GPS systems are now almost as indispensable as car radios. But just how do these devices work and what makes them so valuable are questions that make those who have not taken the plunge wonder if they are worth the price of admission.