How Does Your Car's GPS Work?

Stephen Fogel
March 8, 2019

GPS navigation

Using GPS in your car for directions and navigation is routine these days. Whether it’s built into the vehicle, a freestanding unit, or on your smartphone, GPS is a reliable, easy-to-use system that makes driving less stressful and keeps you from getting lost.

Before GPS, drivers had to make do with printed paper maps, which were not practical to use while driving. Typing in an address or landmark and pressing “Go” is much more convenient (just make sure to do it safely). 

Let’s take a look at the history of GPS, how it works, additional benefits and the future of GPS.

The history of GPS

As with many technological advances of the 20th century, GPS was originally conceived of and developed for the U.S. military. The system is based on the concept that satellites can be used to determine the exact positions of things on Earth. 

Using 32 satellites that orbit the planet, the system is still owned by the government but is publicly available. The first built-in GPS in a car appeared in the late 1990s, in the BMW 7 Series. The use of the system as an aid to navigation quickly spread. 

How does GPS work?

The GPS satellites orbit the Earth twice each day at an altitude of 12,540 miles. These satellites travel west to east at a speed of 8,000 miles per hour. An atomic clock on each satellite provides the most precise timekeeping possible.

As you drive your car, your GPS receiver connects to the microwave signals sent out by at least four of the nearest GPS satellites. By finding exact distance from each satellite, the system can identify the exact spot where your car or phone is located at any given moment. 

When combined with the interactive mapping software in your GPS receiver, the satellite signals can guide you to your destination. Traffic patterns can also be monitored, allowing you to avoid congestion and accidents and arrive sooner and more relaxed.

» MORE: Find a certified mechanic near you

Other benefits of having GPS

GPS technology has other car-related uses besides mapping a route for you. These include:

Notifying first responders if you crash: Telematics systems like OnStar and others can use GPS to pinpoint your location if you have an accident. They’re alerted by a signal that your airbags have gone off or your car has rolled over, and can also tell if there are people in the car by whether the seat belts are buckled. Armed with this information, their call centers can dispatch rescue services directly to the scene.

Integrated smartphone apps: Many carmakers offer a phone app that can be used to remotely start your car, lock and unlock it, and locate it — using GPS — in case you lose it in a large parking lot.

The future of GPS

As we get closer to the time when self-driving cars become part of the traffic on our roads, GPS will be play a key role in the mapping systems that make them safe.

Self-driving cars will need to know exactly where they are at all times, with much greater accuracy than is currently provided by GPS. Tomorrow’s system will have to work flawlessly with the cameras, radars, sensors and software that will take the human driver out of the equation.

These cars will also need to talk to each other and the traffic system infrastructure so that they can all work together to provide an efficient and accident-free transportation future. 

Stephen Fogel

About the Author

Stephen has been an automotive enthusiast since childhood, owning some of his vehicles for as long as 40 years, and has raced open-wheel formula cars. He follows and writes about the global automotive industry, with an eye on the latest vehicle technologies.