GPS
The first gps was used by the United States in 1960.
The gps navagation is able to provide fix approximately
once per hour. the navy developed the timation satillite
which had then approved ability to place satellite and
accurate clocks in space, A team of scientist were monitoring
spuntnik's radio tranmissions. they realized that since they
know their exact location on the globe, they could pinpoint where the
satellite was long its orbit by measuring the droppler distortion.

• The importance for the function of GPS is crucial and it is the placement of atomic clocks in the satellites, which was proposed by Friedwarat Winterberg in 1955.