Mankind used different methods in establishing a standard of time scale before,
of which the method of astronomical observation is still being in used. Astronomers
observe the orbits of the sun, moon and stars to measure time, and astronomic
observation is based on the Earth's rotation. However, the Earth's rotation
is not uniform, so the demand of accuracy in modern times cannot be met. Hence,
it is essential to establish a standard of time scale to ensure the accuracy
of time. Time service authorities world-wide are using the atomic clock as a
standard of "time scale", in which they synchronize time and frequency signals
to together for comparison before disseminating time signals to the public.
This service is called "Time Service".
The Seismic Monitoring Centre of Macao Meteorological and Geophysical Bureau (SMG) is responsible for generating and disseminating the standard of time scale in Macao. Formally, GPS time signal was disseminated to the citizens of Macao through radio broadcast after it has been received by SMG. Because of the development of science and technology and with the implementation of the service of e-Government, the range of our service is being enhanced and a new set of atomic clock and time server is being added in 2003 so as to provide time service more rapidly and accurately to the citizens of Macao.