Important Notice

FURUNO ELECTRIC CO., LTD.
Marine Electronic Products Division
First Posted : 2019-02-06
Posted : 2019-03-20
Posted : 2020-04-02

We thank you very much for your trust in and continued support for our products and services.

It is regretful to announce that there is a possibility that some of our GPS products (please see the list below) may face GPS errors after the 17th of March 2019, due to the problem of GPS week number rollover. If you happened to spot any errors on the equipment listed below, we would like you to take the following countermeasures to resolve the problem. If the problem persisted after having taken the countermeasures, please consult with our sales representative closest to your location. We sincerely apologize for all the inconveniences caused.

NOTE: The date specified below is the date in which week number rollover occurs in our products listed below, and the date is independent from the one announced by the US Department of Homeland Security, namely, the 6th of April 2019, which is the date when GPS week number rollover occurs in the GPS as a system per se. The difference stems from different initial dates of counting week between GPS system and the GPS chipset used in our products.

Added equipments that will be affected on 2021/06/20.

1.List of equipment that may be affected by the GPS week number rollover

Rollover Occurrence Date: 2022/01/02

Type of Equipment	Model
GPS NAVIGATOR	GP-80 / GP-90 / GP-90-DUAL / GP-150* / GP-150-DUAL* / GP-70MK2 / GP-500MK2 / GP-32 / GP-33*(Serial No.6412-8194 or earlier)
DGPS NAVIGATOR	GP-37
GPS RECEIVER	GP-320B / GP-330B (Serial No.4457-7001 or earlier)
GPS/PLOTTER	GP-1640 / GP-188 / GP-280 / GP-380 / GP-680 / GP-8000 / GP-8000MK2
GPS/PLOTTER/SOUNDER	GP-1640F
COLOR GPS/PLOTTER	GP-1650W / GP-1850W / GP-7000 / GP-3500* / GP-1800 / GP-1800MK2 / GP-3000 / GP-3050 / GP-3100 / GP-3100MK2 / GP-3300
COLOR DGPS/PLOTTER	GP-1650WD / GP-1850WD
COLOR DGPS/PLOTTER/SOUNDER	GP-1650WDF / GP-1850WDF
COLOR GPS/PLOTTER/SOUNDER	GP-1650WF / GP-1850WF / GP-7000F / GP-3500F*/ PS-8000 / PS-8000NK2
PLOTTER/SOUNDER	PS-1000
RADAR PLOTTER SOUNDER	FRS-1000
SATELLITE COMPASS	SC-30* / SC-50* / SC-110*
AIS	FA-50* / FA-150*
INMARSAT	FELCOM15* / FELCOM16* / FELCOM18* (Serial No.4507-4045 or earlier) / FELCOM19* (Serial No.3599-2507 or earlier)
WEATHER STATION	WS-200

Rollover Occurrence Date: 2021/06/20

Type of Equipment	Model
GPS NAVIGATOR	GP-32 / GP-80 / GP-90 / GP-90-DUAL
DGPS NAVIGATOR	GP-37
GPS RECEIVER	GP-320B
GPS/PLOTTER	GP-1640
GPS/PLOTTER/SOUNDER	GP-1640F
COLOR GPS/PLOTTER	GP-1650W / GP-1850W / GP-3500
COLOR DGPS/PLOTTER	GP-1650WD / GP-1850WD
COLOR GPS/PLOTTER/SOUNDER	GP-1650WF / GP-1850WF / GP-3500F
COLOR DGPS/PLOTTER/SOUNDR	GP-1650WDF / GP-1850WDF

Rollover Occurrence Date: 2019/03/17

2.Natures of the error and its cause

The GPS system is synchronized to a different time scale than Coordinated Universal Time (UTC) and calculates time by counting the number of weeks up to 1,023rd week.After week 1,023, the week number count is reset to zero. This is called "GPS week number rollover". Subsequently, the erroneous date information on the GPS receiver clock may result in instability in positioning, causing position errors, including failure of GPS position acquisition, etc.

3.Procedure for checking the integrity of the equipment and counter measures to be taken

Please carry out the following counter measures:

1. Since the nature of the problem of "GPS week number roll-over" is the erroneous date information on the receiver clock, the equipment that does not require date information would be unaffected by the problem in question. If, by any chance, the positioning performance became instable, you would be able to resolve the problem of positioning integrity by cold-starting the equipment through the operating menu. Please note, however, that even though you regain the GPS position acquisition, the date information cannot be restored merely by cold-starting.
2. If the positioning integrity is not restored after cold start, the problem may stem from the failure of the equipment, not from GPS week number roll-over. If such is the case, please consult with our sales representative closest to your location.
3. If you want to return the date data to normal for the models with * (asterisk), you can replace the GPS receiver inside the device or update the software (both for a fee).

NOTE

If the GPS product is interfaced with any of the following equipment and systems, the countermeasures would have to be taken, for the date information is utilized by the interfaced equipment and systems.

• GMDSS radio installation, incl. internal GNSS receiver of Inmarsat-C terminal
• Ship Security Alert System (SSAS)
• Vessel Monitoring System (VMS)
• Equipment that displays route information such as ECDIS
• Voyage Data Recorder (VDR)
• Automatic Identification System (AIS)
• Equipment that records ship tracks such as Color video plotter
• Other equipment and systems that utilizes the date information from GPS receiver clock

For further information and consultation, please contact your nearest point of contact of FURUNO.

Contact US

For information about your nearest point of contact of FURUNO, please visit:
https://www.furuno.com/en/support/distributors/