These days, you would see GPS watches of different brands and styles everywhere. Each boasting of competitive features and functionalities that promise to help you progress on your fitness journey. But are you among us who wonder how do GPS watches work?
How Do GPS Watches Work?
Your GPS watch uses, well, GPS to get your exact location through triangulation, which is the process of determining the difference between the time that your device receives a signal from satellites, and the time when that signal is sent to your device.
The GPS receiver, which is integrated into your GPS watch, will then use this data to determine how far your device is from the satellites. Your GPS watch will measure a series of points to calculate metrics such as speed, pace, and distance accurately.
What About the Satellites?
So, how do satellites work in space, and how are they related to GPS? A network of 24 satellites with known positions orbits the earth in a precise path to send microwave signals to GPS receivers which then use the data for triangulation to determine your exact location.
A GPS receiver needs to detect at least four satellites to be able to calculate your longitude, latitude, and elevation. Note though that the more satellites in view, the more accurate the results are. This process happens continuously, measuring time lag and distance from the other satellites in relation to you as the GPS receiver in your device keeps track of them as you move.
What About Elevation?
An elevation measurement is a distance between the surface of the earth and a point below or above it. But because the earth’s surface is constantly changing and is full of physical anomalies, scientists tend to rely on vertical data which are abstract representations of the surface of the earth.
You can get elevation information from your GPS device. Many fitness devices or watches make use of barometric altimeters to get accurate readings and measure the pressure changes from different elevation levels when you exercise or workout so that you can get real-time elevation change data.
What About Accuracy?
There are times when you have ran the same route as your buddies, but your devices show different readings. You may be thinking, “Why did it give me a different distance?” or “How come I took way more steps today than yesterday on the same route?” Here are some possible ways that cause the discrepancy:
- Different Device Model
Among the major reasons could be because you use a different device model which uses a different process of receiving, filtering, and logging GPS signals.
Additionally, the quality of the antenna, which detects the signals provided by the satellites, and the number of tracking channels may also cause this discrepancy. Unfortunately, there can even be larger discrepancies if you traveled long distances.
Some devices also have battery-saving options which can decrease the accuracy of measurement from your GPS. Other devices also use satellite orbit predictions which provides data for a short time and can be refreshed when a data connection is used.
- The Satellite Position
As previously discussed, the more satellites used, the better the level of accuracy is. These satellites orbit Earth, and so the number