NEWS
Notice of GPS week number rollover on GPS Navigator / Sensor
product
2026.01.27To All Customers:
We greatly appreciate your use of our products.
This is to inform you of the “GPS week number rollover” problem and how it affects our GPS Navigator / Sensor.
The GPS system calculates time by counting the number of weeks up to a maximum of 1,023 weeks. After week 1,023, the week number count is reset to zero. This is called “GPS week number rollover”.
The GPS week number rollover occurs every 1,024 weeks – about once every 19.6 years. Therefore, when 19.6 years has passed from the reference date in the systems, the clock time incorporated in GPS sensors and navigators will be reset, causing as a result errors in display or output of date, or unstable occurrence in positioning operation.
When GPS week number rollover occurs, our GPS Navigator / Sensor may cause the following problems:
- Date displayed dates back to 19.6 years ago.
- All dated data output by equipment date back to 19.6 years ago.
- Due to this inaccurate date, positioning operation may temporarily become unstable or be interrupted.
When this rollover has occurred, please switch on the equipment twice to recover the normal positioning operation. After recovery of the operation, the date will remain as it is in 19.6 years ago, but time and positioning operation will function normally.
We regret any inconvenience this may cause you, but appreciate your kind understanding in this matter.
Sincerely yours,
Affected GPS Navigator / Sensor and Countermeasures
- When the dated data displayed on equipment and the dated data output from equipment are not used, there would be no need to take countermeasures. When data is continued to be used, either one of the following countermeasures shall be taken:
- Upgrade of software version.
- Replacement of equipment (When equipment can not be dealt with by upgrade of software version).
Please refer to the tables below for countermeasures for each type of equipment.
It is possible to postpone the occurrence of rollover to the year of 2028 by upgrading of software, but it may not be possible to upgrade software, even if charge is paid, as the needed ROM software may not be available on all models. In such cases, replacement of equipment will be provided with charge. Please contact our distributors / dealers where you have purchased or our marine sales department for details on the equipment subject “upgrading of software version”. We appreciate your kind understanding that the cost shall be born by you for either case of the countermeasure above mentioned.
- Even on the same equipment models, this phenomenon may occur on a different date, due to its software number and version number. The tables below list the earliest possible date of occurrences.
Table 1 – GPS Sensors
| Date of rollover occurrence | Model Name | Serial Number | Countermeasures |
|---|---|---|---|
| August 15, 2010 | GPS-4A | All | Unit replacement is necessary Please contact your nearest distributor |
| GPS-5 | All | ||
| February 5, 2012 | GPS-4Amk2 | All | Unit replacement is necessary Please contact your nearest distributor |
| GPS-6 | All | ||
| January 20, 2013 | GPS-10 | All | Unit replacement is necessary Please contact your nearest distributor |
| GPS-10A | All | ||
| KBG-1 | All | ||
| KBG-2 / DGPS-11 | All | ||
| August 1, 2021 | GPS-20A | 02097323 and before | Unit replacement is necessary Please contact your nearest distributor |
| From 02097324 to 02097358 | GPS module software upgrading (*) Please contact your nearest distributor | ||
| KBG-3 | 00302555 and before | Unit replacement is necessary Please contact your nearest distributor | |
| From 00302556 to 00302682 | GPS module software upgrading (*) Please contact your nearest distributor | ||
| November 5, 2028 | GPS-20A MkⅡ | All | Unit replacement is necessary Please contact your nearest distributor |
| GPS-21 | 02191200 and before | Unit replacement is necessary Please contact your nearest distributor | |
| December 2, 2029 | GPS-20A | 02097359 and after | GPS module software upgrading (*) Please contact your nearest distributor |
| KGB-3 | 00302683 and after | ||
| April 7, 2041 | GPS-21 | 02191201 and after | Unit replacement is necessary Please contact your nearest distributor |
Table 2 – GPS Compass / GPS Navigators
| Date of rollover occurrence | Model Name | Serial Number | Countermeasures |
|---|---|---|---|
| August 15, 2010 | KGP-95 / GPS-7 | All | Unit replacement is necessary Please contact your nearest distributor |
| KGP-97 / GPS-8 | All | ||
| KGP-910 / 910A | All | ||
| GPS-77P | All | ||
| KGP-911 / GPS-88P | All | ||
| KGP-930 | All | ||
| February 5, 2012 | KGP-98 / 98D | All | Unit replacement is necessary Please contact your nearest distributor |
| GPS-9 / 9D | All | ||
| KGP-931 | All | ||
| January 20, 2013 | KGP-9 / HG-7 | All | Unit replacement is necessary Please contact your nearest distributor |
| KGP-912 / GPS-99P | All | ||
| KGP-913 / 913D | All | ||
| GPS-90 / 90D | All | ||
| KGP-931D | All | ||
| August 1, 2021 | KGP-920 | 92002298 and before | Unit replacement is necessary Please contact your nearest distributor |
| From 92002299 to 92002415 | GPS module software upgrading (*). Please contact your nearest distributor | ||
| KGP-913MkII | 91332146 and before | Unit replacement is necessary Please contact your nearest distributor | |
| From 91332147 to 91332250 | GPS module software upgrading (*) Please contact your nearest distributor | ||
| February 19, 2023 | KGC-1 | 00101312 and before | Software upgrading Please contact your nearest distributor |
| August 15, 2027 | From 00101313 to 00101791 | ||
| April 1, 2029 | 00101792 and after | ||
| December 2, 2029 | KGP-920 | 92002416 and after | GPS module software upgrading (*) Please contact your nearest distributor |
| KGP-913MkII | 91332251 and after | ||
| September 1, 2030 | KGC-222 | 22201288 and before | Software upgrading Please contact your nearest distributor |
| April 16, 2033 | KGP-915 | All | **Unit replacement is necessary |
| KGP-922 | All | ||
June 2, 2035 | KGP-915 | All | **Unit replacement is necessary |
| KGP-922 | All | ||
| KC-1400 | All | GPS module software upgrading (*) Please contact your nearest distributor | |
| August 18, 2035 | KGC-222 | 22201289 and after | Unit replacement is necessary Please contact your nearest distributor |
| KGC-300 | All | No action required The rollover date will be updated automatically | |
| September 27, 2036 | KGP-915 | All | **Unit replacement is necessary |
| KGP-922 | All |
**Due to the built-in GPS module version, there are three possible rollover dates, but the specifications do not allow distinction by serial number. Please contact your nearest distributor before April 2033.
Table 3 – Navigation and Multifunction display
| Date of rollover occurrence | Model Name | Serial Number | Countermeasures |
|---|---|---|---|
| August 15, 2010 | GTD-07 | All | *Turn on the unit twice |
| GTD-2000 | All | Unit replacement is necessary Please contact your nearest distributor | |
| GTD-2020 | All | *Turn on the unit twice | |
| GTD-210 | All | Unit replacement is necessary Please contact your nearest distributor | |
| GTD-2200 / 2200X | All | *Turn on the unit twice | |
| GTD-2210 | All | ||
| GTD-2400 | All | ||
| GTD-2410 | All | ||
| February 5, 2012 | GTD-1100 | All | Unit replacement is necessary Please contact your nearest distributor |
| GTD-2010 | All | *Turn on the unit twice | |
| January 20, 2013 | GTD-1200 | All | Unit replacement is necessary Please contact your nearest distributor |
| November 20. 2038 | KTN-70A | All | Unit replacement is necessary Please contact your nearest distributor |
| KTN-70AF | All | ||
| KSD-1100 | All | No action required The rollover date will be updated automatically | |
| KSD-1210 | All |