GPS (Global Positioning System) - Facts for Kids

History & Development

GPS was invented by the United States Department of Defense in 1973 to help military ships and aircraft know exactly where they were in the world!

The first GPS satellite (called Navstar 1) was launched into space on February 22, 1978, beginning a new era of navigation technology!

Dr. Bradford Parkinson is often called the Father of GPS because he directed key parts of the GPS system — from the design of the satellites and control stations to pushing through the idea when it was just a plan.

The GPS system’s full operational capability (with 24 active satellites in their assigned orbits) was declared on April 27, 1995 — after more than 20 years of development.

Before GPS, sailors used to navigate by looking at the stars, using maps (charts), and special instruments like sextants to find their way!

In May 2000, President Bill Clinton let everyone stop using the weaker GPS signal — ending something called Selective Availability. From then on, civilians got GPS that was nearly as accurate as the military’s!

The original GPS satellites were expected to last only 7.5 years, but many have worked for over 20 years!

Scientists and engineers worked on GPS for more than two decades before it was ready for everyone to use!

The first handheld GPS device for regular people came out in 1989 and weighed 1.5 pounds — as heavy as a large bottle of water!

Early GPS receivers could take several minutes to figure out their location — way slower than today’s super-fast devices!

How It Works

GPS satellites orbit Earth at about 12,550 miles (20,200 km) up in the sky, and the system is built around a “constellation” of 24 main satellites. (Earth’s tallest mountain, Mount Everest, is about 5.5 miles high — so that’s like stacking nearly 2,280 Everests!

Each GPS satellite circles Earth about twice a day (one orbit ≈ 11 hours 58 minutes). They travel at about 8,700 miles per hour (≈ 14,000 km/h) relative to Earth.

GPS satellites are powered by solar panels, which collect sunlight to make electricity. They also carry backup batteries to keep working when they’re in Earth’s shadow (during eclipse periods).

Your GPS device usually needs signals from at least four satellites to pinpoint exactly where you are. Three satellites help find your position in space, and the fourth fixes any tiny clock errors in the device, so the answer is precise.

GPS satellites carry super-accurate atomic clocks that are so precise, they usually gain or lose about one second every 3,000 years!

GPS signals travel at the speed of light — about 186,000 miles per second. At that speed, light could zoom around Earth nearly 7.5 times in one second!

GPS works by measuring how long it takes radio signals to travel from satellites to your device — like playing a giant game of cosmic ping-pong!

Some older GPS satellites weigh around 2,000 pounds (about 900 kg) in orbit — lighter than a small SUV. But newer ones can be much heavier, up to 4,800–10,000 pounds (2,200–4,500 kg), depending on how big and powerful they are!

GPS can find your location almost anywhere on Earth within about 10 meters — that’s roughly the length of a school bus!

GPS signals can pass through clouds, glass, and plastic, but they have trouble going through solid objects like buildings or mountains!

GPS signals can pass through clouds, glass, and plastic, but they have trouble going through solid objects like buildings or mountains!

Cool Capabilities

GPS can help track the migration patterns of animals like whales, birds, and sea turtles!

GPS can detect movements in Earth’s crust as small as a fraction of an inch, helping scientists study earthquakes!

GPS systems can calculate your speed without using any special sensors — just by tracking how quickly your position changes!

GPS works everywhere on Earth, from the North Pole to the South Pole, and even in airplanes high in the sky!

GPS can help farmers plant crops in perfectly straight lines using special tractors that drive themselves!

GPS time is so accurate that banks and computer networks around the world use it to keep their systems synchronized!

GPS radio signals pass through clouds, rain, day or night. What matters is whether there is a clear line-of-sight to enough satellites.

Smartphones often use assisted GPS and combine signals (e.g. from cell towers or WiFi) to speed up location fixes.

Real-World Uses

When someone is in trouble, GPS can tell exactly where they are — even if they can’t speak or don’t know nearby roads — so rescue teams can zoom in and help fast!

Pizza delivery drivers often use GPS so they can find your house, avoid getting lost, and make sure your pizza arrives quickly — while it’s still hot!

Planes use GPS to help fly safely from one airport to another — they get help from extra systems so they can even land precisely when the weather is bad or in places without big navigation beacons!

Geocaching is a fun treasure hunting game where people use GPS to find hidden containers all over the world!

Construction workers use GPS to make sure tall buildings are built perfectly straight!

GPS helps ship captains navigate safely through oceans and avoid running into dangerous rocks or shallow water!

When hiking in the wild, GPS can help you know exactly where you are, find your way to your campsite again, and stay safe if trails get confusing — as long as your device is charged, maps are loaded, and you’ve got a backup plan!

Phone apps use GPS to help you find nearby restaurants, stores, and fun places to visit!

Fun Tech Facts

There are over 6 billion GPS devices in use around the world — that’s almost one for every person on Earth!

The oldest working GPS satellite still in orbit has been operating for over 25 years!

Even at the top of Mount Everest (over 29,000 feet high), GPS devices can work — people have used them to measure the mountain and help climbers stay safe!

One of the early GPS satellites (Navstar-7) failed during its launch and fell into the ocean — but scientists kept going, and GPS still became a success!

GPS satellites are arranged in six orbital planes around Earth — you can think of them like six invisible “highways” in space.

A GPS signal takes about 0.067 seconds to reach your device from a satellite — less than the blink of an eye!

GPS satellites carry special sensors that can detect nuclear explosions anywhere on Earth to help keep everyone safe!

Everyday Applications

Pokémon Go and other AR games use GPS to figure out where you are in the real world — then they “place” virtual creatures or objects on your screen so it looks like they’re part of your surroundings.

Parents can use GPS watches or trackers to help see when their children arrive at school — but it depends on the watch’s accuracy, signal, and setup.

Many pets wear GPS collars so they can be found quickly if they get lost!

Lots of buses use GPS to track their position in real time — then they use that to guess when the bus will arrive at each stop, so passengers don’t have to wait too long.

Sports watches use GPS to measure how far you run, bike, or swim (especially in open water), and to help you see your speed, time, and path.

Wildlife photographers use GPS to remember exactly where they took their best animal pictures!