The ITU Radiocommunication Assembly considering a) that it is desirable to maintain coordination of standard frequency and time-signal emissions in the vicinity of the Earth; b) that universal coordinated time (UTC) is the official coordinate time scale for the Earth defined on the rotating geoid; c) that atomic clocks are subject to path-dependent second-order motional frequency shifts and position-dependent gravitational frequency shifts; d) that the Consultative Committee for the Definition of the Second (CCDS) has recognized the need for well-defined procedures to account for relativistic effects in timing systems and time comparisons; e) that, since time comparisons in non-inertial frames require special consideration and the CCDS has recommended an appropriate set of equations which provide a consistent set of measurements of UTC in the vicinity of the Earth; f) that there is a growing trend to place accurate, stable clocks in Earth-bound orbits for time-keeping purposes; g) that there is a need for comparing frequency standards in the vicinity of the Earth with an accuracy of 10-14.