What GPS tools would you choose in a big city now? Generally, TomTom, Magellan and Garmin will come into your sight. With the popularity of smart phones, everyone can have a GPS 。 But do you know how GPS works?

Global Positioning System (GPS) is actually a term for satellite monitoring. At present, there are 24 satellites circling the earth. The first satellite was launched in 1978, and the 24 satellites were fully launched in 1993. The system was officially put into use in 1995. The system costs 10 to 12 billion dollars, and the annual cost of maintenance is estimated to be about 400 million dollars. Each satellite weighs 2000 pounds and uses solar power to power it. It takes 11 hours and 58 minutes to circle the earth once and twice a day. The altitude is 10600 miles (high altitude).

The original reason for establishing the satellite system was that the United States wanted to deploy military weapons. The system code was NAVSTAR. In 2000, President Clinton opened the system to the world System.

At any time, your mobile GPS system will receive the positioning from 4 to 12 satellites. The entire satellite orbit forms a birdcage shaped surrounding system. Through the triangle positioning technology, your GPS device can tell you the exact position. For example, it uses high-frequency and low-power radio signals to spread at the speed of light through the three satellites in front of it, and then calculates the distance between these satellites and the equipment. Because these satellites have a fixed orbit mode and are synchronized with the atomic clock of the US Naval Weather Observatory, this process will generate an accurate position reading. But in order to be more accurate, GPS systems usually capture signals from multiple satellites, especially when When.

As long as GPS knows where you are, it can determine the map route, speed, and other location information, such as sunrise and sunset at a certain location in the other half of the earth. Over time, the accuracy of GPS will be slightly affected by the sun and moon, but the US Defense Agency will regularly send updated data to the satellite system for correction.

The GPS system is very useful for walking, cars, boats and aviation. Thanks to the introduction of many applications, the stage of GPS has become larger and larger. The closest example to life is that the government uses relevant technologies and shares urban traffic data to alleviate urban traffic problems.

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