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Leap Second

Configuration of leap seconds include two parameters: initial GPS-to-UTC offset (due to accumulated leap second events) and future leap second event.

To set a leap second event, navigate to Select > [Select Scenario] > Configure [selected scenario]: View 2/3 > LS:.

Leap second configuration

The leap second event field can be set to -1, 0 or 1, and indicates a future change in GPS-to-UTC offset value.

Initial GPS-to-UTC offset (ΔtLS) can be initialized automatically by the scenario start time (using history information about actual leap second events), or by navigation data files. Alternatively, the user can also specify any desired offset value. This is configured under the scenario menu: Advanced > GPS to UTC offset, or by using the scenario file parameter GpsToUtcOffset.

The allowed values are:

  • Auto: In this setting, the initial offset is determined by scenario start time
  • Rinex: determined by information taken from navigation data files attached to a scenario
  • <Fixed Offset in Seconds>: the user can select an offset from a range of 0-30

An up-to-date leap second events history is embedded in each firmware release, but you can also download the latest list from the Internet using Options > Advanced options > Download leap seconds list.

Considerations

Note that downloaded and default navigation data files do not contain any LSF information (RINEX v2.1). Therefore, it is still necessary to set the LSF when a leap second change will occur, in order to ensure correct behavior.