Below is the "official" notice of the ILRS Leap Second Procedure" sent several times this year.

Dear Prediction, Station, and Analyst Colleagues,

As you are probably aware, there is a leap second at the end of December 31 this year. Our last couple of leap second experiences could have been better. This time, the ILRS has adopted the following simplified policy approved by the Data Formats and Procedures Standing Committee and the ILRS Central Bureau.

1) Stations:

    - On December 31, track as normal up until the end of the UTC day.

    - On January 1 UTC, be sure your stations clock is updated, and switch to the CPF files that start on

        January 1. Do NOT use CPF files that start in December.

    - Tracking a satellite pass through the December 31/January 1 crossover will probably not work

        properly.

2) Prediction providers:

    - Most of you do not need to change anything. It does not matter whether you are setting the leap

        second flag or not, as long as it it is set consistent with the CPF document.

    - The CPF files starting on January 1 and thereafter MUST NOT have the leap second flag set to '1'.

        After the last leap second, one or two providers did not reset the flag for a few days into January.

    - Be sure to have your leap second files updated properly.

3) Analysts:

    - Be sure to update your leap second files!

This procedure should be easier than dealing with leap second flags, although some passes that span the leap second will be lost. Let us know if you have any issues with this procedure.

Best regards,
Randall Ricklefs
For the ILRS Central Bureau