Normally today things are easier to get, for less than $100; you can get a pocket-sized device that will tell you exactly where you are on earth at any time. As long as you have a GPS (Global Positioning System) receiver and a clear view of the sky, you'll never be getting lost in any weather conditions. Most of the people know only that the GPS can give you Position, Velocity, and Time, but they don't know exactly when the GPS was initially created and how is it works from the time they switch it ON till they start to navigate.
Nowadays, there are at least 24 operational GPS satellites at all times plus a number of spares. The satellites, operated by the United States Department of Defence, orbit with a period of 12 hours (two orbits per day) at a height of about 11,500 miles traveling at 9,000mph (3.9km/s or 14,000kph). Ground stations are used to precisely track each satellite's orbit. So GPS was originally created by the U States DOD as a military application. The system has been active since the early 1980s, but began to become useful to civilians in the late 1990s
The simple way to explain behind GPS is this: If you know how far away you are from three known points, you can use high school math to determine exactly where you are. Here's how it works when those known points and those measurements come from outer space Global Positioning System satellites transmit signals to equipment on the ground. GPS receivers passively receive satellite signals no transmit. GPS receivers require an unobstructed view of the sky, so they are used only outdoors and they often do not perform well within forested areas or near tall buildings.
Each GPS satellite transmits data that indicates its location and the current time. All GPS satellites synchronize operations so that these repeating signals are transmitted at the same instant. The signals, moving at the speed of light, arrive at a GPS receiver at slightly different times because some satellites are farther away than others. The distance to the GPS satellites can be determined by estimating the amount of time it takes for their signals to reach the receiver. When the receiver estimates the distance to at least four GPS satellites, it can calculate its position in three dimensions.
As we can see now, GPS can know where you are anywhere on the surface of the planet. Since the GPS is receiver from the satellite, it means the line of sight should be there, otherwise the accuracy will be less and hard for the GPS to locate position. GPS is small device but there is a big process behind it.
Normally today things are easier to get, for less than $100; you can get a pocket-sized device that will tell you exactly where you are on earth at any time
.... I wish you rephrased the first part of this line... What are the things that you can easily buy for less than $100? Not very clear :(
As long as you have a GPS (Global Positioning System) receiver and a clear view of the sky,you'll never be getting lost in any weather conditions.
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you will never get lost under any weather condition.Most of the people know only that the GPS can give you Position, Velocity, and Time, but they don't know exactly when the GPS was initially created and how is it works from the time they switch it ON till they start to navigate.
Most of the people only know that GPS provides accurate information about Position, Velocity, and Time, but they lack knowledge about how GPS works