### ... like I'm 5 years old

GPS, which stands for Global Positioning System, is a tool that helps you know where you are. Imagine you're in a new city, unsure of where to go. You whip out your phone, open a map application, and it pinpoints your exact location. The magic behind this process is GPS.

GPS relies on a network of satellites orbiting the Earth. When your device needs to find out where it is, it sends a message into space. This message is picked up by the satellites, which send back their own messages to your device. Your device then calculates the time it took for the messages to travel from the satellites to your device, and this allows it to determine your exact location.

Think of the GPS as a game of cosmic "Marco Polo." You shout "Marco!" (your device sending a message), and several satellites respond with "Polo!" (sending their own messages). By listening to how long it takes for the "Polo!" to reach you, you can figure out how far away you are from the satellites, and pinpoint your location.

### ... like I'm in College

The Global Positioning System (GPS) is a satellite navigation system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth.

The system operates independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the GPS positioning information. There are currently 31 operational satellites in the GPS network, which orbit the Earth twice a day in a precise formation.

GPS receivers work by using a method called trilateration. In simple terms, trilateration involves the measurement of distances. By knowing the exact location of three or more satellites and the distance between the receiver and each satellite, the receiver can determine its location on Earth.

Let's imagine a simplified GPS system using Lego bricks. Suppose we have three Lego towers (our satellites) and one Lego figure (our GPS receiver).

The Lego figure wants to find out where it is in relation to the towers. It sends out a signal (imagine this like a shout), which each tower hears. The time it takes for the signal to reach each tower depends on how far away the figure is from each tower.

By figuring out how long it took for its signal to reach each tower (how long it took each tower to hear its shout), the Lego figure can figure out how far away it is from each tower. With this information, it can pinpoint its exact location.

Just like our Lego figure, a GPS receiver sends out a signal that is picked up by satellites. The time it takes for the signal to reach each satellite tells the receiver how far away it is from each satellite, and it uses this information to determine its precise location.

### ... like I'm an expert

The Global Positioning System is a highly sophisticated navigation system based on a constellation of 31 satellites orbiting the Earth at an altitude of approximately 20,200 kilometers. Each satellite broadcasts a signal that includes both the precise time the signal is sent, based on an atomic clock, and the exact orbital position of the satellite.

GPS receivers calculate their position by precisely timing the signals sent by the satellites. The receiver measures the time delay for the signal to reach the receiver, which gives the receiver the distance to each satellite, given that the signal travels at a known speed (the speed of light).

The receiver uses the time delay of the received signals from four satellites to solve for the four unknowns: x, y, z, and t (time). This process is referred to as trilateration.