Modern space technology is at the forefront of scientific and technological progress. Satellite communication, which is used in a wide variety of spheres of human life, has become the technological basis for a global system of atomic time synchronisation. Its flawless operation is particularly important for navigation systems and communication networks.

Atomic clocks define a standard for a second based on quantum transitions between the energy levels of molecules and atoms. International Atomic Time (TAI), established by the International Bureau of Weights and Measures, is the result of averaging data from several hundred geographically distributed atomic clocks. This data needs to be constantly synchronised. TWSTFT (Two-Way Satellite Time and Frequency Transfer) - synchronisation via a dedicated satellite channel with guaranteed equal delay of signal transmission in both directions - is considered the most accurate method of comparing readings of atomic clocks located in laboratories around the world. Two stations simultaneously transmit synchronised signals through a geostationary satellite and accurately measure the difference between the transmitted and received signals down to one nanosecond.

One advantage of TWSTFT is its capability to exchange data simultaneously while transmitting time pulses, as the satellite transponder has a sufficient throughput for this purpose. Thus, in fact, the system operates in real time. Equally important, the stations can be very far apart. Another advantage of TWSTFT is the symmetry of the scheme: when using the same transponder, the uplink and downlink signal paths are physically the same. The immobility of the geostationary satellite relative to the earth stations of the system and the use of antennas with a diameter of a metre or more also improve the accuracy of measurements.

Intersputnik is involved in the atomic clock synchronisation and International Atomic Time averaging system. The Organization provides satellite bandwidth to metrology laboratories and institutes in several countries, including China, Germany, India, Japan, Korea, Poland, Russia. The prospective development of the Intersputnik international system takes into account the possibility of increasing the number of laboratories connected to the international satellite system of atomic time synchronisation.