How a GPS Device Works

How Does a GPS Device Function? 

A GPS (Global Positioning System) device works by receiving signals from a network of satellites in orbit around the Earth. These satellites transmit a precise time signal and information about their location. The GPS device uses this information to calculate its own position on the Earth’s surface.

To determine its position, the GPS device needs to receive signals from at least four GPS satellites. When the device receives the signals, it calculates the time it took for each signal to reach it, based on the time stamp sent by the satellite. By knowing the time it took for each signal to arrive, and the location of each satellite, the GPS device can calculate its own position using a process called trilateration.

Trilateration involves using the time it took for the signals to arrive from each satellite to calculate the distance between the GPS device and each satellite. By knowing the distance to at least three satellites, the GPS device can determine its position on the Earth’s surface. The fourth satellite is used to correct any errors in the calculations due to factors such as atmospheric interference.

Once the GPS device has determined its position, it can provide the user with information such as their latitude, longitude, altitude, and speed. This information can be used for navigation, tracking, and a variety of other purposes.

What is the technology they use?

Nothing more than the satellites! They synchronize with the 24 operational satellites and fix up some errors arising out of the obstacles, either artificial or natural. Find more below.

GPS is short for Global Positioning System, and that captures well what it does: it indicates your position on the globe. The way GPS operates is a fascinating tale that doesn’t require advanced mathematics to understand.

Before looking into how navigation systems work, it’s helpful to know how certain positions on Earth are specified. The classic view provides one that’s easy to visualize.

Imagine a simple grid that wraps the globe ‘vertically’ originating at the Earth’s North Pole and stretching out over to the South Pole. Then add ‘horizontal’ lines that cross the globe at right angles to the vertical lines. That grid is the familiar longitude and latitude ‘mesh’ found on every schoolroom globe and map. Each line of lat and long is divided in degrees that specify how far along a line you are located.

Now, what does the ‘mesh’ have to do with the GPSes system?

The U.S. Air Force maintains 24 different operational GPS satellites (with 3 spares). Each satellite has the electronics and software installed to calculate its location, most importantly the distance to the Earth. It does that by sending a radio beam out and registering the time needed to hit the Earth, where ground stations pick up the signal.

A simple formula is distance = velocity * time, and that describes it pretty straightforwardly. Radio waves travel at the speed of light (~186,00 mph or ~300,000 kph), and the electronics measure the delay from when the beam is sent to when it hits the target.

Satellites (and ground stations) can measure that delay accurately because they have computers synchronized by atomic clocks that can measure time incredibly accurately. GPS Receivers don’t have atomic clocks included but perform some tricks to compensate.

Also, because of variations in the atmosphere, the motion of the satellites, reflections from buildings, and other imperfections, GPS has to make up for small calculation errors to get the precision needed to locate your GPS receiver within a few meters.

Distance provides only one important factor in GPS. Imagine you’re told you are 600 miles east of Los Angeles. That puts you in the center of a circle of 600 miles, with LA somewhere on the circumference (the rim). But you don’t know exactly where. You’re told you are also a few hundred miles north of Las Vegas, and another circle is created. Those two circles intersect at two points. A third intersecting circle will place you at exactly one unique point (to within measurement accuracy).

Satellites and GPS Receivers

Since the GPS is dependent on satellites in space that interact with ground stations, it operates in three dimensions, not just the two provided by the surface of the Earth. So, the Global Positioning System works with spheres rather than circles. The calculations are more complex, but the idea is the same. Where the surfaces of four spheres intersect, they calculate a certain point, the location point of the GPS device.

Your GPS receiver is designed to ‘listen’ for the signals from four of those satellites and uses the info provided to determine your latitude and longitude. It overlays that unique point onto a map that resembles your surrounding area to help you navigate your way to anywhere in the world.


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Personal GPS Tracking Device

I never realized just how helpful would a personal GPS tracking device be. A personal GPS tracker is very useful in case you often hike to remote locations. I utilize it regularly when I go to foreign countries, given that I like discovering new places on my own with solely the help of a GPS unit and compass. I likewise carry it in my automobile regularly as a safeguard in case my motor vehicle gets taken. Furthermore, I know some individuals who utilize a personal GPS tracking device to spy on where their spouse or kids are going. I’m not indicating this is the correct thing to do, but it is beneficial to know that you may likewise utilize a personal GPS tracking device in this manner.

GPS covers a large area of communication concepts. Understanding it is very difficult. But here, a brief idea is given about it. After reading it, one can understand what GPS is all about. But still, much information is there to know about it.

I saw a segment about the Global Positioning Satellite Devices in Space. According to Stephen Hawking’s, Into the Universe, the effects of time go slower closer to Earth than in space. Gravity has an effect on time which slows time down. So basically, these GPS satellites are “getting older” faster than objects/humans on Earth.

Read More: The Ultimate Guide to Tools for Spatial Data Collection