GPS week rollover issue

I just came across this interesting page: https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some older instruments it could mess up the date. How many of our soaring instruments might have this problem?

Jonathan

On 2/6/19 10:00 AM, Jonathan Foster wrote:
I just came across this interesting page: https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some older instruments it could mess up the date. How many of our soaring instruments might have this problem?

Jonathan

There's some potential for problems, but some of the firmware has been
hacked to delay the actual appearance of the problem for years in the
future. I doubt there's going to be a big ripple of problems in April.

At 17:00 06 February 2019, Jonathan Foster wrote:
I just came across this interesting page:
https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some older
instruments it could mess up the date. How many of our soaring
instruments
might have this problem?

Jonathan

Any of them, but the older instrument the more likely it is to have a
problem.

The date is transmitted by the satellite as a day oy the week and a week
number. there are 11 bits available for the week number (0-1023) and a
rollover occurs every 1024 weeks (an Epoch) or 19 years 8 months approx.

As the GPS engine in the instrument does not receive the Epoch number from
a satellite, it relies on a Battery Maintained Real Time Clock on the GPS
Engine module. If the battery fails or is allowed to become discharged,
Epoch 0 may be assumed, which it probably isn't. Epoch 0 started 6th Jan
1980 originally, but some recorders may have a different date set to fix
previous rollover problems.

The RTC battery should hold up for six months or so, but as the battery
becomes older, the capacity may decrease, reducing the figure. The best
advice seems to be to connect your instrument just before 6th April to
allow the GPS Engine battery to charge. And pray. If you Recorder has the
right date after 6th April 2019 all is well and good, but never allow the
RTC battery to become discharged.

If you have the wrong date after 6th April, it is a Return-to-Manufacturer
repair.

Good Luck!

Tim, thanks for that explanation. Is this what happened to the Cambridge instruments that needed an update to keep working several years ago?

On Wednesday, February 6, 2019 at 10:45:04 AM UTC-7, Tim Newport-Peace wrote:
At 17:00 06 February 2019, Jonathan Foster wrote:
I just came across this interesting page:
https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some older
instruments it could mess up the date. How many of our soaring
instruments
might have this problem?

Jonathan

Any of them, but the older instrument the more likely it is to have a
problem.

The date is transmitted by the satellite as a day oy the week and a week
number. there are 11 bits available for the week number (0-1023) and a
rollover occurs every 1024 weeks (an Epoch) or 19 years 8 months approx.

As the GPS engine in the instrument does not receive the Epoch number from
a satellite, it relies on a Battery Maintained Real Time Clock on the GPS
Engine module. If the battery fails or is allowed to become discharged,
Epoch 0 may be assumed, which it probably isn't. Epoch 0 started 6th Jan
1980 originally, but some recorders may have a different date set to fix
previous rollover problems.

The RTC battery should hold up for six months or so, but as the battery
becomes older, the capacity may decrease, reducing the figure. The best
advice seems to be to connect your instrument just before 6th April to
allow the GPS Engine battery to charge. And pray. If you Recorder has the
right date after 6th April 2019 all is well and good, but never allow the
RTC battery to become discharged.

If you have the wrong date after 6th April, it is a Return-to-Manufacturer
repair.

Good Luck!

My old Cambridge gps had to be sent back to be reset.Â* What about the
ClearNav or PowerFlarm portable?

On 2/6/2019 10:56 AM, Jonathan Foster wrote:
Tim, thanks for that explanation. Is this what happened to the Cambridge instruments that needed an update to keep working several years ago?

On Wednesday, February 6, 2019 at 10:45:04 AM UTC-7, Tim Newport-Peace wrote:
At 17:00 06 February 2019, Jonathan Foster wrote:
I just came across this interesting page:
https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some older
instruments it could mess up the date. How many of our soaring
instruments
might have this problem?

Jonathan

Any of them, but the older instrument the more likely it is to have a
problem.

The date is transmitted by the satellite as a day oy the week and a week
number. there are 11 bits available for the week number (0-1023) and a
rollover occurs every 1024 weeks (an Epoch) or 19 years 8 months approx.

As the GPS engine in the instrument does not receive the Epoch number from
a satellite, it relies on a Battery Maintained Real Time Clock on the GPS
Engine module. If the battery fails or is allowed to become discharged,
Epoch 0 may be assumed, which it probably isn't. Epoch 0 started 6th Jan
1980 originally, but some recorders may have a different date set to fix
previous rollover problems.

The RTC battery should hold up for six months or so, but as the battery
becomes older, the capacity may decrease, reducing the figure. The best
advice seems to be to connect your instrument just before 6th April to
allow the GPS Engine battery to charge. And pray. If you Recorder has the
right date after 6th April 2019 all is well and good, but never allow the
RTC battery to become discharged.

If you have the wrong date after 6th April, it is a Return-to-Manufacturer
repair.

Good Luck!

--
Dan, 5J

A number of Legacy Cambridges had problems. They use the Garmin GPS25
Engine and lets face it, the batteries are very old now. I believe that CAI
replaced the GPS Engine, which includes the RTC Battery.

ClearNav are more recent by far, so are unlikely to be affected.

I'm not sure about Flarm, why not ask them?

Tim.

At 18:40 06 February 2019, Dan Marotta wrote:
My old Cambridge gps had to be sent back to be reset.Â* What about the
ClearNav or PowerFlarm portable?

On 2/6/2019 10:56 AM, Jonathan Foster wrote:
Tim, thanks for that explanation. Is this what happened to the
Cambridge
instruments that needed an update to keep working several years ago?

On Wednesday, February 6, 2019 at 10:45:04 AM UTC-7, Tim Newport-Peace
wrote:
At 17:00 06 February 2019, Jonathan Foster wrote:
I just came across this interesting page:

https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some
older
instruments it could mess up the date. How many of our soaring
instruments
might have this problem?

Jonathan

Any of them, but the older instrument the more likely it is to have a
problem.

The date is transmitted by the satellite as a day oy the week and a
week
number. there are 11 bits available for the week number (0-1023) and a
rollover occurs every 1024 weeks (an Epoch) or 19 years 8 months
approx.

As the GPS engine in the instrument does not receive the Epoch number
from
a satellite, it relies on a Battery Maintained Real Time Clock on the
GPS
Engine module. If the battery fails or is allowed to become
discharged,
Epoch 0 may be assumed, which it probably isn't. Epoch 0 started 6th
Jan
1980 originally, but some recorders may have a different date set to
fix
previous rollover problems.

The RTC battery should hold up for six months or so, but as the
battery
becomes older, the capacity may decrease, reducing the figure. The
best
advice seems to be to connect your instrument just before 6th April to
allow the GPS Engine battery to charge. And pray. If you Recorder has
the
right date after 6th April 2019 all is well and good, but never allow
the
RTC battery to become discharged.

If you have the wrong date after 6th April, it is a
Return-to-Manufacturer
repair.

Good Luck!

--
Dan, 5J

I'll post information pertinent to ClearNav products here and on the CN user forum as soon as I have the official story.

-Evan

On Wednesday, February 6, 2019 at 5:15:04 PM UTC-5, Tim Newport-Peace wrote:
A number of Legacy Cambridges had problems. They use the Garmin GPS25
Engine and lets face it, the batteries are very old now. I believe that CAI
replaced the GPS Engine, which includes the RTC Battery.

ClearNav are more recent by far, so are unlikely to be affected.

I'm not sure about Flarm, why not ask them?

Tim.

At 18:40 06 February 2019, Dan Marotta wrote:
My old Cambridge gps had to be sent back to be reset.Â* What about the
ClearNav or PowerFlarm portable?

On 2/6/2019 10:56 AM, Jonathan Foster wrote:
Tim, thanks for that explanation. Is this what happened to the
Cambridge
instruments that needed an update to keep working several years ago?

On Wednesday, February 6, 2019 at 10:45:04 AM UTC-7, Tim Newport-Peace
wrote:
At 17:00 06 February 2019, Jonathan Foster wrote:
I just came across this interesting page:

https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some
older
instruments it could mess up the date. How many of our soaring
instruments
might have this problem?

Jonathan

Any of them, but the older instrument the more likely it is to have a
problem.

The date is transmitted by the satellite as a day oy the week and a
week
number. there are 11 bits available for the week number (0-1023) and a
rollover occurs every 1024 weeks (an Epoch) or 19 years 8 months
approx.

As the GPS engine in the instrument does not receive the Epoch number
from
a satellite, it relies on a Battery Maintained Real Time Clock on the
GPS
Engine module. If the battery fails or is allowed to become
discharged,
Epoch 0 may be assumed, which it probably isn't. Epoch 0 started 6th
Jan
1980 originally, but some recorders may have a different date set to
fix
previous rollover problems.

The RTC battery should hold up for six months or so, but as the
battery
becomes older, the capacity may decrease, reducing the figure. The
best
advice seems to be to connect your instrument just before 6th April to
allow the GPS Engine battery to charge. And pray. If you Recorder has
the
right date after 6th April 2019 all is well and good, but never allow
the
RTC battery to become discharged.

If you have the wrong date after 6th April, it is a
Return-to-Manufacturer
repair.

Good Luck!

--
Dan, 5J

Our very own Y2K bug. To be fair, they designed it before 2000 made us all worry about such things, but still, maybe they could've allocated an extra hex character.

9B

On Wednesday, February 6, 2019 at 9:00:44 AM UTC-8, Jonathan Foster wrote:
I just came across this interesting page: https://www.orolia.com/resources/blo...-you-need-know

On April 6th of this year the GPS week will roll over and on some older instruments it could mess up the date. How many of our soaring instruments might have this problem?

I'm guessing that will be the final end of my 1994 Cambridge Model 10. (It's already had the battery replaced, of course)

At 02:12 07 February 2019, Andy Blackburn wrote:
Our very own Y2K bug. To be fair, they designed it before 2000 made us
all
worry about such things, but still, maybe they could've allocated an
extra
hex character.

9B

It is just transmissions on the L1 frequency that have this limitation.
Transmissions on L2 & L5 do not, but GPS Engines in Flight Recorders use
L1,
presumably on cost grounds.