3/14/2023 0 Comments Gps week number![]() *5: For more information, and countermeasures, please contact us. Notice and countermeasures are same as this. *4: Next rollover of KE51719 and after will be May 2022. *3: Next rollover of KE50479 and after will be May 2022. ![]() ![]() *2: Next rollover of KE54239 and after will be May 2022. *1: Next rollover of BB51401 and after will be August 2025. Note that time and date will go back to the starting date (December 19, 1999) when a master-reset of equipment or a battery replacement is carried out after rollover day. notice and countermeasures below or click here to download the file. The subject models are designed to turn the clock back 19.6 years (December 19, 1999), and will continue to work incorrectly under normal use, however there is no influence on positioning operation.įor details, please see the 2. JRC announces measures for GPS week number rollover for equipment that is to occur on some of the GPS' on 4th August 2019. Due to this inaccurate date, the positioning operation may temporarily become unstable or be interrupted.All dated data output by equipment date back to 19.6 years ago.Date displayed dates back to 19.6 years ago (19 December 1999).When GPS week number rollover occurs, our GPS navigator and or sensor may show the following erroneous phenomena: Therefore, when 19.6 years have 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. The GPS week number rollover occurs every 1,024 weeks which means about once every 19.6 years. This is called “GPS week number rollover”. After week 1,023, the week number count is reset to zero. The GPS system calculates time by counting the number of weeks up to a maximum of 1,023 weeks. Should your equipment be on one of these lists we will be happy to assist you in either arranging upgrade of software or installing new equipment.This newsletter contains information in regard to the "GPS week number rollover" and how this affects JRC's GPS receivers and the GPS incorporated equipment. At a minimum, we recommend consulting your receiver manufacturer to confirm that the issue has been fully tested and will not occur.īelow are statements from some of the major suppliers - click on the supplier name and read their statement: In these cases, we want to verify that an issue will not occur. Receiver is a core component of a critical timing system – ask yourself – what is the impact to my system if the GPS receiver stopped operating or put out wrong GPS or UTC information.Receiver has been fielded for more than 10-15 years without firmware updates.You should be concerned, though, if either of the following applies: Should I Be Concerned?īecause this it is the second time the GPS week rollover will occur, many receiver manufacturers have prepared for it, and newer receivers will continue to operate without issue. ![]() Using this method, the problem could occur, but at a different date and year than the actual GPS rollover date. Another way is to shift that 1023 window with reference to some firmware or manufacture date within the receiver. It is also possible for the user to modify this reference date in some receivers. This works well if the receiver is new or is receiving firmware updates. One common method is to use the firmware date as a reference. To do this, receivers use various methods to ensure that they are providing the correct date. Receivers must properly interpret that week number as the correct date, not 19.7 years into the past or future. The next time the counter will reach week 1023 and rollover to zero is on April 6, 2019. The week counter then reset to zero, and it has been recounting ever since. The 1024 weeks counter ran out and rolled over on August 21, 1999. The next time the counter will reach week 1023 and rollover to zero is on April 6, 2019 This limits the range of the week number to 0 – 1023, or 1024 total weeks. However, the field that contains the week number is a 10-bit binary number. This allows the receiver to translate the date and time into a more typical format – day, month, year, and time of day. It also includes the ability to transmit the proper date and time to a receiver by supplying the receiver with the current week and the current number of seconds into the week. The Global Positioning System provides accurate timing information to many of our critical systems – AIS, GPS, Speedlog and SATCOM systems to name a few.
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