When I searched for “rollover” on FurunoUSA’s Forum, it was no surprise that some tropical cruisers experienced issues right after the Jan.
#Gps week number update
Furuno Forum moderator explains update options.Furuno user in the South Pacific with failed AIS transceiver after recent rollover.Then again, the wrong system date can cause major problems… What will a GPS rollover mean on your boat? Moreover, an unfixable GPS date is not necessarily an insurmountable problem, and I think I’ve found a solid way to use the PB200’s remaining faculties (as discussed below). It turned out that Airmar is aware of the problem but they say it can’t be fixed, and they further note that rollover is not an issue for the GPS chipsets in the many WeatherStation models that superseded the PB200 many years ago. For instance, I only powered up the 13-year-old PB200 WeatherStation because Kees Verruijt encountered the rollover in his test lab over the holidays.
#Gps week number series
So what we have here is a series of rolling rollovers that are apparently only being publicized by the manufacturers, if at all. In fact, Furuno’s long-posted GPS rollover notice lists equipment that rolled over on or 6/20/21 or earlier this month, and JRC announced rollovers that will happen on the 15th of May. Coast Guard were already warning boaters about it and many marine electronics companies offered firmware fixes.īut few of us realized then that many devices got through the 1999 rollover without problems only because their GPS receiver chipsets had been jiggered to push the 1,024-week date change forward a couple of years or more. When Ben Stein well explained the latter rollover, organizations like the U.S. The root cause of GPS week number rollover is a well-known programming limitation in the early GPS satellite transmissions, and it’s happened twice so far - at midnight August 21, 1999, and again on April 6, 2019. Furuno announced a GPS week number rollover date affecting many older devices The date changes will undoubtedly mess up some boaters in the months ahead, so let’s make ourselves aware. Yes, the problem seems like the well-publicized April 1999 GPS week number rollover, except that it just happened a few weeks ago on the attached Airmar PB200, and lots of older gear from Furuno, JRC and probably other brands are experiencing a similarly delayed and under-publicized rollover in 2022.
#Gps week number upgrade
Customers still using OEM4s are encouraged to upgrade to the latest NovAtel platform (OEM7) prior to September 2022.While I certainly knew that it was not Jwhen I took this photo last Saturday, the Sunrise/Sunset times shown above are also quite wrong, and it’s hard to tell what other calculations get screwed up when a networked device like this Maretron DSM starts receiving a system date that is 1,024 weeks old. OEM4: The latest firmware on the OEM4 family of receivers is 2.322, with a current base week that is valid until September 24, 2022, 11 years beyond the end of service date. This may impact receiver operation if it is interacting with an external system that is sending data with a different GPS week number as there will be a time mismatch.
![gps week number gps week number](https://kb.meinbergglobal.com/_media/kb/identify_gnss_receiver/receiver_info_lantime_v6_m300_gps180.png)
However, the GPS week reported by the receiver will be incorrect. When the receiver’s base week is no longer valid, the receiver will continue to operate and output a correct position. What happens when the receiver base week is not valid? This allowed the NovAtel receivers to successfully transition over the era rollover that happened on April 6, 2019. From time to time, NovAtel has updated the pre-configured date in a new firmware version to allow the receiver to determine the correct era for the next 10-18 years. In order to help the receiver determine the actual calendar date, NovAtel has historically pre-configured a date as a reference to figure out the current GPS “era”. This “era” rollover happened in 1999, and again on April 6, 2019. This means that roughly every 19 years the GPS week goes back to zero and starts incrementing again. The GPS ICD defined navigation data format limits the number of weeks before a rollover to 1023. GPS Time is reported in weeks since January 6, 1980. While the receivers will continue to operate, this may cause interoperability issues with receivers that are reporting a different week number. However, as of September 24, 2022, OEM4 receivers will start reporting a GPS week number in the past.
![gps week number gps week number](https://venturebeat.com/wp-content/uploads/2018/09/IMG_20180903_102707-1.jpg)
Due to the high quality of the OEM4 receivers, some receivers are still in service over 20 years later. OEM4s were subsequently end-of-life’d in 2006 and reached end of service in 2011. OEM4 receivers were first introduced to the market over two decades ago, providing high precision, dual constellation, dual frequency multi channel GNSS receivers to the world.