This issue affects only GLONASS-enabled receivers. GLONASS tracking will be temporarily interrupted on receivers operating during the introduction of the leap second on December 31st, 2016. GPS tracking will not be impacted, and receivers will continue to compute a position using the GPS constellation. OEM6 receivers may report a solution integrity warning during this period. GLONASS tracking will return to normal once a new GPS almanac is automatically downloaded from the satellites by the receiver. Receivers powered-up after the introduction of the leap second that do not have a current almanac will also temporarily have difficulty tracking GLONASS satellites. An almanac will not be available on start-up if the receiver has not been used in 90 days or if the almanac has been cleared manually by the user. GPS tracking will not be impacted, and receivers will continue to compute a position using the GPS constellation. OEM6 receivers may report a solution integrity warning during this period. GLONASS tracking will return to normal once a new GPS almanac is automatically downloaded from the satellites by the receiver.
Solution:
The condition introduced by the leap second is temporary in nature and receiver functionality will return to normal when a new GPS almanac is automatically downloaded by the receiver. The total expected duration of the GLONASS tracking disruption is expected to be less than 60 minutes.
Recommended Minimum Firmware Version
We always recommend that our GNSS receivers are running the latest firmware, however we understand the practicality’s involved in making this happen.
With this in mind, the Leica Geomatics team has carried out a full review of our GNSS instruments back to version System 1200.
Based on this review and testing using simulated GNSS data, we can provide the following recommendations for minimum firmware versions to use in order to avoid any disruptions: