35. Impact Analysis of the Leap Second to the Computer System in Beijing Aerospace Control Center

It analyzes the impact of the leap second at 07:59:60 July 1, 2012 to the timing system and applications in Beijing Aerospace Control Center (BACC), and proposes a solution for the leap second adjustment. First it introduces the source of the leap second. Next it articulates the timing system device, timing system clients, timing system topology, as well as their working mechanism. Then it describes the experiments on the leap second adjustment, presents the test contents, procedures, and results under the automatic and manual adjustment modes. It also presents the test results of the leap second adjustment under the NTP protocol. The test results indicate that the timing system devices work well under both automatic and manual adjustment modes, and the clients can synchronize with the timing system device in 4 s. When the adjustment is executed on the timing system device, the clients can synchronize with the timing system device after a pause of one second at the synchronization point. As for the NTP conditions, the clients can not synchronize within 5 min, and can synchronize immediately if the clients are rebooted. The leap second will make a big impact on the time-sensitive systems such as the TT&C devices and applications. It suggest that the leap second adjustment and synchronization need to be executed outside the critical command and control procedures, and a thorough implementation plan needs to be made. The most important point is that the synchronization must be after a delay of 4 s in the leap second adjustment.