Placed in the 1980s was GPS available for civilian use by an Executive Order. Until then, it was primarily limited to military purposes, as mentioned. The civilians were able to use low-power radio signals from the satellite broadcast in the L1 frequency. The other L2 frequency was reserved for military purposes. The use of GPS by "Selective Availability was restricted" clause of the U.S. military.

Explosion in commercial use:

With the removal of this clause, the use of GPSexploded. A large number of applications were found for GPS. By tracking your pet to keep track of children and elderly people back from finding your location in remote campsite and find your way to civilization, from the search for breakdown service for an accident to an emergency tracking tool for an accident victim , 911 to fire departments, public transport, the pursuit of their vehicles and courier services, tracking your packages and their drivers, companies, managementtheir logistics more efficiently to search for a hidden treasure on a global fun game. GPS has brought a whole new world of applications, which was probably not from the creators of the system considered.

Military purposes:

The GPS primarily developed for the military troops to help them on their way to see the country, has remote control has Afghanistan and Iraq. During Operation Desert Storm "of U.S. troops heavily on GPS systems to find their way into the remote, featureless desert of Iraqand Kuwait. It helps in the identification of targets, sending troops and many other applications that are familiar to us.

Is it free?

GPS is available free of charge. Finally, it is your tax money pays for them in the first place.

Is it reliable?

The U.S. Department of Defense control and utilize them, then it has to be reliable. The system of 24 satellites are designed so that at some point, a GPS receiver on the ground receives signals from at least 4 satellites if not more. Should one or more satellitesfails, then they are back to take up to 4 satellites to their place. And the U.S. defense budget includes the replacement of satellites, and if a satellite goes out of service.

Ground control stations on Earth to continuously monitor and keep the data on the state via satellite. If the satellite orbits assume the master control station sends commands to get it back into orbit. Help backup battery boosters and on board the satellites, the systems work in times of need to consider howduring a solar eclipse or when the orbital correction is necessary.

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