Since the GPS project was launched in 1973, its satellite signal has been the source of controversy. This was the idea of a colonel named Bradford Parkinson, who was disillusioned with the wanton air battle in Vietnam and designed GPS as a method to improve the precision of precision bombing. The Parkinson's disease research team has designed two versions of GPS signal jammers, one for civilian use and the other for military use, with stricter security protocols and more accurate readings. However, when the first GPS satellite was launched, people soon realized that civil signals were more accurate than their architects had expected. Smart scientists found that although the information content of military signals has been highly encrypted, the radio signals themselves are not difficult to obtain.
The company is owned by the Department of Defense, operated by the U.S. Air Force in a highly secure room at the Colorado base, and is free of charge for anyone in the world. There are 24 GPS satellites in the world, orbiting 20000 kilometers. Each satellite sends out a radio signal, which contains a time code and a description of the exact location of the satellite. By measuring the signal transmission time, the GPS receiver can determine its distance from the satellite. If the receiver simultaneously receives signals from at least four satellites in the line of sight, its position can be inferred from three dimensions. In about 67 milliseconds, the signal reaches our hands and becomes extremely weak. In the 1990s, the Pentagon deliberately destroyed civilian signals - a practice known as "selective availability" - in the hope of preventing terrorists or other villains who might use signals to launch precise attacks.
However, the user also found a solution here. An order by President Bill Clinton came into force in 2000, which halted the Pentagon's plans. Global Positioning System. Now it can realize its full potential. Soon, the civilian GPS industry is booming. By the middle of this century, the sales of Garmin, a large GPS user company, exceeded 1.6 billion dollars. Motor vehicles are soaring at a rate of more than 140% every year. The prosperity of car GPS has certainly been replaced by the prosperity of smartphones: GPS is now something you can carry with you. However, the explosive growth of the civilian GPS market has also prompted people to try to destroy signals. Today, GPS jammers are sold for hundreds of dollars on the Internet, providing an easy way for anyone who is worried about employer monitoring. Global Positioning System. For reasons unrelated to geographical positioning, "geographic information system" is now crucial.
Since the GPS clock is synchronized to the nanosecond level, the network signal is used for the time-related system with uniform distribution in a large range. Global Positioning System. Time facilitates the call back between cellular towers, regulates the energy flow in the grid, and adds timestamps to financial transactions on major stock exchanges. If the deceiver provides wrong information, or even confuses the clocks of multiple nodes in these systems, the damage may be extensive: with the increase of time error, the communication system may fail, and the energy distribution may be uneven, leading to power failure and automatic trading procedures May exit the market and cause accidents.
These are only a few cases. Four years later, in June 2017, the French tanker Atria crossed the Mediterranean Sea and crossed the Bosporus Strait into the Black Sea. When the ship was sailing towards Novorossisk, Russia, captain Gurvan Le Meur noticed that the navigation system of the ship seemed to lose its GPS signal. The signal came back soon, but the position given was far away. The Atria was apparently located about 40 kilometers inland and crashed at the airport of the Russian resort of Gelenjik.
