Maintaining the Timeline Reliability in the Master Network Clock in Conditions of Deliberate Interference

Time synchronization systems are based on the formation of the time scale by the master network clock equipment and transfer of data about the current value of time to the slave clocks of consumers. At the same time, to maintain stable operation of endpoints, it is necessary to correctly generate timestamps of the master time server. For this purpose, communication channels with national time and frequency standards are used, including the most common channel - the reception of signals of global navigation systems. However, the reception of GNSS signals can be disrupted by various types of interference - natural or deliberate interference, including spoofing, i.e. substitution of satellite signals with false ones. At the same time, the master clock either loses the ability to obtain data on a single time scale, or receives invalid data on the time code or the initial phase of the second interval. The use of terrestrial channels for receiving time stamps can also lead to timing errors due to various kinds of failures that can occur in the transmission system from the national standard to the master clock. Thus, when creating complexes of master network clocks, it is necessary to use special technical solutions to control the accepted time stamps and maintain the reliability of the formed time scale.