Relativity - correction 

The effect of gravitational frequency shift on the GPS system due to general relativity is that a clock closer to a massive object will be slower than a clock farther away. Applied to the GPS system, the receivers are much closer to Earth than the satellites, causing the GPS clocks to be faster by a factor of 5×10^(-10), or about 45.9 μs/day. This gravitational frequency shift is also a noticeable effect.

There is a mistake. Yes, it is true, that the clock father away will be faster due to the weaker gravitional field. However, in case of orbiting satellites the effective gravitational field is completely canceled by the acceleration (remember totaly weightless astronauts in the orbit). According of the postulate of the general relativity theory an steady acceleration is equivalent to a homogenuos gravitational field - the satellite is in the effective zero-field.
Thus, the factor 45.9 μs/day must correspond to zero-field time dilatation, not somewhat-weaker-field time dilatation.