FURUNO Singapore News & Events

“GPS Rollover on 20th June 2021”

15 February 2021

We would like to inform valued customers and users of FURUNO GPS marine products of the GPS week number rollover occurring on 20th June 2021.

This happens because the GPS system calculates time by counting to 1023 weeks, after which, the count resets to zero. This is called the “GPS Week Number Rollover”. Subsequent erroneous data information on the GPS receiver clock may result in position instability, causing position errors, including failure of the GPS position acquisition etc.

List of Affected Equipment

Rollover Occurrence Date: 20th June 2021

GP-3500FBefore 3484-0893GP-1650W

Before 3474-3690 and

3474-3706 to 3473-3733

GP-80All serial numberGP-1650WDBefore 3476-6430
GP-90Before 4400-6461GP-1650WFBefore 3475-0200
GP-1640Before 3458-0700GP-1650WDFBefore 3477-0254
GP-1640FBefore 3459-0950GP-1850WBefore 3478-1813
GP-320BBefore 3473-6767GP-1850WFBefore 3480-2745
GP-32Before 4439-1803GP-1850WDBefore 3479-0594
GP-37 (GP-37-J)Before 4441-3005GP-1850WDFBefore 3481-1225


  • – To update the software for GP-3500 & GP-3500F to software V.06.03.
  • – For other models, retrofit to latest model.
  • Note: Cold-starting will not restore date information.


Contact us for more information:

For Retrofits: salesgrp@furuno.sg

For Software Upgrade: sdc@furuno.sg

Click here for more details.