Japan Radio Co,. Ltd. Notice : GPS Week Number Rollover for equipment

Dear Customers,

We would like to announce that GPS week number rollover ^＊1 for equipment is to occur on some of our GPS' on 8th September 2024 or 3rd August 2025.

The subject models are designed to turn the clock back 19.6 years (23th January 2005), and will continue to work incorrectly under normal use, however there is no influence on positioning operation.
However, as the results, the following abnormalities occur in some equipment.

• Some date information will be displayed erroneous.
• Communication function will not work properly.

For details, please see the 2. notice and countermeasures below.

*1 GPS week number rollover :
The week number counter in GPS resets once every 1023 weeks, which is approximately 19.6 years. The week number counters for the GPS in the objective equipment below started their week count from 23rd January 2005. It is on 8th September 2024 at 00:00 AM (UTC) that the week number counters rollover will occur.

1.Objective Equipment

1-1.Rollover date: 8th September 2024

• Inmarsat Fleet Broadband FB500（JUE-500）
• GPS navigator（JLR-7500/7600）
• GPS receiver（JLR-4331W/4340）
• GPS compass（JLR-20/30）

1-2.Rollover date: 3rd August 2025

• AIS（JHS-182/183）
• GPS navigator（JLR-7800/7900）
• GPS receiver（JLR-4341）
• GPS compass（JLR-21/31）

2.Notice and Countermeasures

2-1.The rollover day is on the 8th September 2024 at 00:00 AM (UTC).

2-2.The rollover day is on the 3rd August 2025 at 00:00 AM (UTC).

*2 : For more information, and countermeasures, please contact our service agents or sales representatives.
For the software update, the corresponding cost will be charged.

Japan Radio Co., Ltd.
Marine Business Department
TEL : [phone]