Global Positioning System Rollover week—06 April 2019

[Alita49DS]

For your information, the Australian Maritime Safety Authority has issue the following notice. Which would appear to have worldwide application. Whether it impacts you would seem to be a matter or how modern your GPS system(s) are:-

Purpose

This marine notice advises Global Positioning System (GPS) users of potential issues that may occur with older GPS receiver time and positional accuracy as a result of the scheduled GPS week counter roll over on 06 April 2019.
NAVAREA X 012/19 has been issued to inform shipping of potential issues.

Background

The GPS system transmits time to GPS receivers using a format of time and weeks from a start date of 06 January 1980. GPS Rollover week occurs when the data field in the navigational message sent by GPS satellites reaches the maximum limit of 1023 weeks and ‘rolls over’ to week zero. This last occurred in August 1999.
Some older GPS receivers are unable to make the transition from week 1023 back to week zero. If your GPS receiver is outdated or has not had a software update, it may revert to reading the week zero as August 1999. When this happens, the internal clocks of these GPS receivers will experience a lack of absolute reference and may give incorrect time or position information, or may lock up permanently. Some GPS receivers may experience issues and disruptions prior to or after the rollover date.
Some GPS receivers are repairable with upgrades, but others may become unusable. Newer receivers that are fully compliant with GPS ICD-200 should not encounter any issues.

Considerations

You should check with your GPS manufacturer regarding the status of your receiver. If you have any doubt as to whether your receiver is compliant you should contact the manufacturer or supplier.
A advises that GPS users should navigate with caution, having due regard for the potential errors that may occur with GPS receivers.

The link is www.amsa.gov.au/marine-notice-01-2019

If anyone contacts to Raymarine or other suppliers to find out which, if any, of their systems might be impacted perhaps they would post here.

[john61ct]

https://www.nws.noaa.gov/om/marine/G...verEffects.pdf

[belizesailor]

Just finished a short near coastal run (San Blas to Bocas del Toro). One planning consideration was to finish before the 6th!

Tomorrow is the big day and I can see what my old Raymarine gear does while comfortably at anchor in Bocas.

[SeanPatrick]

From a post on NavList:

Originally Posted by Paul Hirose on NavList

The origin of the GPS time scale is 1980 January 6 00:00:00 UTC =
00:00:19 TAI = Julian date 2 444 244.5 + 19s TAI.

A week number rollover occurs every 1024 weeks, and this will be the
second rollover in GPS history, so add 2 * 7 * 1024 days to obtain JD 2
458 580.5 + 19s TAI = 2019 April 7 00:00:19 TAI.

Until the next leap second, UTC is 37s behind TAI. Therefore, April 7
00:00:19 TAI - 37s = April 6 23:59:42 UTC. That's when the rollover occurs.

[PJHoffnet]

My SIMRAD NSS12 (pre-evo) came up with no time/posit data on 7 APR. Pi$$es me off because SIMRAD had just put out an update in NOV '18 for an earlier lack of time issue and they assured me that the fix also would support the GPS week rollover. Checked site and they acknowledge that the older NSS will be affected and they'll let us know when an update is ready.
https://www.simrad-yachting.com/news/gps-week-rollover/

[Gruz]

I think that GlobalSat BU-353 USB GPS does not work any more.

[Pitchondesign]

Raystar 125 gps works.

[belizesailor]

Like Y2K it appears this was mostly a non-event. Was for me.

My primary concern was my old Raymarine instruments. They have been unsupported for years, so no software update available. Booted today to check, took longer than usual to acquire, but eventually came right up with a good fix and correct time and date. Yeeha!

As expected, non of my newer devices aboard had any issues.

Good day for me.

Did anyone experience any problems?

[Alan Mighty]

Originally Posted by Pitchondesign

Raystar 125 gps works.

My RS 125 works too. Or it did yesterday.

But you will have noted Raymarine's advice that we need to replace our RS 125 receivers by 2022 because errors will accumulate, no?

[Reefmagnet]

My trusty old Garmin 152H came up with the correct position and time. But reported the date as sometime in January 2021 and took a L-O-N-G time to acquire satellite positions first time it was started after the rollover.

[Lake-Effect]

so far, my GARMIN 64st is good (better be, it's barely a year old), and my elderly GARMIN etrex Vista is ok, though it took a while to lock.


Haven't yet tried my USB GPS fob.

[J Clark H356]

Anyone have an RN300 GPS working with Pathfinder RL70C. I haven’t been to boat yet?

[Beausoleil]

Originally Posted by J Clark H356

Anyone have an RN300 GPS working with Pathfinder RL70C. I haven’t been to boat yet?

I'm in the same "boat" - our newly acquired Sundancer 390 came with an RN300 and RL70C, plus an E80 Classic. Hope to run down to the marina this week...

[s/v Thea]

Fired up my old handheld garmin 45xl for first time in years. Shows date as Aug 24 1999, it acquired position quickly (considering last time it was used) and position is correct.

[s/v Jedi]

My Maretron GPS200 is reporting the date to be August 23, 2099