15-03-2019, 14:12
Ciao a tutti, a questo proposito riporto il messaggio trasmesso via Safetynet - Inmarsat-C:
NL BURUM LES 80.36.114.192 15-MAR-2019 12:02:03 188680
NAVAREA III 0305/19
MEDITERRANEAN AND BLACK SEAS
POTENTIAL PROBLEMS FOR USERS OF GPS RECEIVERS.
1. USERS OF GPS RECEIVERS ARE ADVISED OF POTENTIAL
PROBLEMS DUE TO GPS WEEK COUNTER ROLL OVER ON
06 APR 19.
2. THE GPS SYSTEM TRANSMITS TIME TO GPS RECEIVERS
USING A FORMAT OF TIME AND WEEKS AFTER THE START
DATE OF 06 JAN 80. THE DATA FIELD IN THE NAVIGATIONAL
MESSAGE SENT BY GPS SATELLITES CONTAINING THE NUMBER
OF WEEKS AFTER THE START DATE IS LIMITED TO A MAXIMUM
OF 1023 WEEKS. WHEN THE GPS SYSTEM REACHES WEEK 1024,
THE SYSTEM WILL REVERT BACK TO WEEK ZERO.
3. SOME GPS RECEIVERS ARE KNOWN TO BE UNABLE TO MAKE
THE TRANSITION FROM WEEK 1023 TO 1024. IF THE GPS
RECEIVER IS OUTDATED OR LACKS PROPER UPDATES,
THE RECEIVER WILL REVERT TO READING THE WEEK ZERO
AS AUGUST 1999. DURING THIS TIME THE INTERNAL CLOCKS OF
THESE GPS RECEIVERS WILL EXPERIENCE A LACK OF ABSOLUTE
REFERENCE AND MAY GIVE THE WRONG TIME AND POSITION OR
MAY LOCK UP PERMANENTLY.
4. SOME OF THESE GPS RECEIVERS ARE REPAIRABLE WITH
UPGRADES AND OTHERS WILL BECOME UNUSABLE. USERS ARE
ADVISED TO CHECK WITH THEIR GPS MANUFACTURER REGARDING
THE STATUS OF THEIR RECEIVER.
5. FOR FURTHER INFORMATION SEE:
A. WWW.GPS.GOV/CGSIC/MEETINGS/2017/POWERS.PDF.
B. WWW.GPS.GOV/GOVERNANCE/ADVISORY/MEETINGS
SELECT NOVEMBER 2017 AND THEN TIMING CRITICALITY
NOTE ON GPS WEEK-ROLL-OVER
C. WWW.GPS.GOV/TECHNICAL/ICWG/IS-GPS-200J.PDF.
6. FAILURE TO VERIFY YOUR GPS RECEIVER COULD LEAD
TO SERIOUS NAVIGATIONAL PROBLEMS PLACING LIVES
AND PROPERTY AT RISK.
NL BURUM LES 80.36.114.192 15-MAR-2019 12:02:03 188680
NAVAREA III 0305/19
MEDITERRANEAN AND BLACK SEAS
POTENTIAL PROBLEMS FOR USERS OF GPS RECEIVERS.
1. USERS OF GPS RECEIVERS ARE ADVISED OF POTENTIAL
PROBLEMS DUE TO GPS WEEK COUNTER ROLL OVER ON
06 APR 19.
2. THE GPS SYSTEM TRANSMITS TIME TO GPS RECEIVERS
USING A FORMAT OF TIME AND WEEKS AFTER THE START
DATE OF 06 JAN 80. THE DATA FIELD IN THE NAVIGATIONAL
MESSAGE SENT BY GPS SATELLITES CONTAINING THE NUMBER
OF WEEKS AFTER THE START DATE IS LIMITED TO A MAXIMUM
OF 1023 WEEKS. WHEN THE GPS SYSTEM REACHES WEEK 1024,
THE SYSTEM WILL REVERT BACK TO WEEK ZERO.
3. SOME GPS RECEIVERS ARE KNOWN TO BE UNABLE TO MAKE
THE TRANSITION FROM WEEK 1023 TO 1024. IF THE GPS
RECEIVER IS OUTDATED OR LACKS PROPER UPDATES,
THE RECEIVER WILL REVERT TO READING THE WEEK ZERO
AS AUGUST 1999. DURING THIS TIME THE INTERNAL CLOCKS OF
THESE GPS RECEIVERS WILL EXPERIENCE A LACK OF ABSOLUTE
REFERENCE AND MAY GIVE THE WRONG TIME AND POSITION OR
MAY LOCK UP PERMANENTLY.
4. SOME OF THESE GPS RECEIVERS ARE REPAIRABLE WITH
UPGRADES AND OTHERS WILL BECOME UNUSABLE. USERS ARE
ADVISED TO CHECK WITH THEIR GPS MANUFACTURER REGARDING
THE STATUS OF THEIR RECEIVER.
5. FOR FURTHER INFORMATION SEE:
A. WWW.GPS.GOV/CGSIC/MEETINGS/2017/POWERS.PDF.
B. WWW.GPS.GOV/GOVERNANCE/ADVISORY/MEETINGS
SELECT NOVEMBER 2017 AND THEN TIMING CRITICALITY
NOTE ON GPS WEEK-ROLL-OVER
C. WWW.GPS.GOV/TECHNICAL/ICWG/IS-GPS-200J.PDF.
6. FAILURE TO VERIFY YOUR GPS RECEIVER COULD LEAD
TO SERIOUS NAVIGATIONAL PROBLEMS PLACING LIVES
AND PROPERTY AT RISK.