On 6 April 2019 there will be a Global Positioning System (GPS) week number (WN) rollover on Coordinated Universal Time derived from GPS receivers and devices.
The GPS system stores the current week number as a 10-bit number. Therefore, every 1024 weeks, the week number rolls over to zero. The start date for the week number count was 6th January 1980. The next rollover event is due on 6th April 2019.
Current Models
TimeTools T-Series Models
TimeTools T100, T300 and T550 models utilize Trimble GPS and Multi-GNSS receivers. The receivers have a software updatable base week to extend the week number. Currently, the week number of these devices will rollover on 9 August 2036.
Summary: No immediate action is required.
Legacy Models
TimeTools SR, SC and LC Series Models
TimeTools SR7110, SR9210, SR9750, SR9850, SR9860D, SC7105, SC9205, SC9705 and LC2750 models utilize earlier model Trimble GPS receivers. The receivers have a base week number derived from the firmware build date.
All models up to serial number SR1443 (manufactured before April 2010) week number rollover: June 2025
All models after serial number SR1443 (manufactured after April 2010) week number rollover: 29 December 2029.
Summary: No immediate action is required.
TimeTools NTP s5000 Series Models
TimeTools s5000, s5100 and s5500 models have been out of production for over 10 years. The GPS receivers used in these models are now obsolete. TimeTools recommends replacing these devices with new T-Series units.
Summary: Action required.
TimeTools tServer Models.
The tServe 5000 series models have been out of production for over 10 years. The GPS receivers used in these models are now obsolete. TimeTools recommends replacing these devices with new T-Series units.
Summary: Action required.
Article Published: June 2018
