Have you ever wondered how GPS works? I have decided to do some explanation here for those who are not familiar.
1. What is GPS?
GPS or Global Positioning System consists of satellites orbiting the earth and it is a system made public by the United States Department of Defense in 1983. Originally meant for military purposes, it is now widely used for GPS services.
Your auto GPS contains a receiver and it receives signals (at a fixed interval) from the many satellites orbiting the earth. To be specific, it receives signals from at least three satellites at any one point of time.
These satellites are programmed to send signals simultaneously, and they allow the receiving device (your auto GPS) to locate its position and determine transmission time. Since the signals travel at the speed of light, knowing the transmission time allows the GPS software to calculate the distance to the satellite (speed x time = distance).
2. Why it Works That Way
Before I go on, you need to know that GPS uses distance (trilateration) to determine location while map and compass use bearings (triangulation) system. If you know how map and compass works, you’ll know that you need three points of reference to pinpoint your location on the map.
Same thing goes for GPS – you need at least 3 satellites to tell your location. Why? Simply because getting to one satellite will tell you where you are in relation to it, but it doesn’t give any clue to your position on earth.
Well, just picture with me. Imagine that you are stuck in the middle of nowhere and a person tells you that you are 100 miles from Chicago. You have no idea which direction that is and it could be anywhere within a 100-mile circle radius.
Therefore, satellites help you to pinpoint your exact coordinates. As I’ve mentioned earlier, you need at least three satellites to do so. If you have four, you’ll get a more accurate location with elevation details.
3. Coordinates Are Not Enough
Coordinates alone won’t be much help. That’s why auto GPS comes with mapping software. From the maps, you get information on roadways and directions (more detailed maps give better directions). These maps are also constantly updated to accommodate road changes.
You’ll need to buy digital maps from map companies. The software works to translate your GPS information and display it unto the map. With the map and satellite signal, you can tell your exact location on road and navigate your way around with ease.
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