User`s guide

Chapter 5 - I/O Commands
LEAP SECOND PENDING MESSAGE (@@Gj)
This command polls the receiver for leap second status information decoded from the Navigation
Data message. The output response provides specific date and time information pertaining to any
future leap second addition or subtraction. Present and future leap second values are also output
rounded to the nearest integer value.
This command only operates in a polled manner, thus it must be requested each time leap
second information is desired.
The ‘present leap second value’ and ‘future leap second value’ are reported from the navigation
data from the satellites. They do not change based on the leap second application time; they will
be updated based on when the navigation data is updated.
Leap seconds are occasionally inserted in UTC and generally occur on midnight UTC June 30 or
midnight UTC December 31. The GPS control segment typically notifies GPS users of pending
leap second insertions to UTC several weeks before the event. When a leap second is inserted,
the time of day will show a value of 60 in the seconds field. When a leap second is removed, the
date will roll over at 58 seconds.
The ‘current UTC offset’ will be zero if UTC is disabled.
Motorola GPS Products - M12+ User's Guide Revision 6.X 09FEB05
152