NOTE:- Round Island boas, (also called Mauritius snakes and splitjaw snakes) are no longer regarded as Boas (Boidae family) and are now in the Bolyeriidae family. There were 2 species, one if which is believed to be extinct.
This is where the Shuttle and ISS conduct their operations. One complete orbit in LEO takes about 90 minutes. Satellites that seem to be attached to some location on Earth are in Geosynchronous Earth Orbit (GEO). These satellites orbit about 23,000 miles above the equator and complete one revolution around the Earth precisely every 24 hours. Satellites headed for GEO first go to an elliptical orbit with an apogee about 23,000 miles.
The receiver multiplies this time by the speed of light to determine how far the signal traveled. Assuming the signal traveled in a straight line, this is the distance from receiver to satellite. In order to make this measurement, the receiver and satellite both need clocks that can be synchronized down to the nanosecond. To make a satellite positioning system using only synchronized clocks, you would need to have atomic clocks not only on all the satellites, but also in the receiver itself. But atomic clocks cost somewhere between $50,000 and $100,000, which makes them a just a bit too expensive for everyday consumer use.