Studying on the Leap Second Calculational Methods in BeiDou System

Abstract

Time is one of the basic reference systems in satellite navigation systems. The time scale of Universal Time Coordinated (UTC) is an atomic uniform time scale, at the same time a leap second is adopted to approach Universal Time (UT). BeiDou Time (BDT) belongs to atomic time systems, and keeps in contact with UTC by leap seconds. User receivers in BeiDou Satellite Navigation System (BDS) calculate a leap second, according to the leap second algorithms in the Interface Control Document (ICD) and navigation messages. User receivers have different interpretations of how to calculate a leap second in BDS, in a result some user terminals did not successfully complete BDT to UTC on 30 June 2015 and 31 December 2016 in time. This paper takes the leap second on 31 December 2016 as an example, introduces how to calculate a leap second in BDS in detail, explains the meanings of time synchronization parameters of BDT to UTC, and shows the leap second calculational methods in each period before and after a leap second, helping user terminals in BDS to correct their leap second calculational methods. It is of an active guiding significance and great reference value for user receivers in BDS.