The locations are most likely calculated using orbit information published by NORAD and/or the spacecraft operators. This is called ephemeris data, and is usual

The locations are most likely calculated using orbit information published by NORAD and/or the spacecraft operators. This is called ephemeris data, and is usually published in a format called "two-line element," or TLE. A TLE contains a complete description of the spacecraft's orbit at a specific time, so you can then calculate where the spacecraft will be at any moment given that it stays in that orbit. See http://www.celestrak.com http://www.celestrak.com for a bunch more information on the subject. Of particular interest is the TLE format itself (http://www.celestrak.com/NORAD/documentation/tle-fmt.asp http://www.celestrak.com/NORAD/documentation/tle-fmt.asp).