Are All Garmin Navigators About The Same At Keeping Time Without A Signal?

 

I powered up one of my Garmin GPS navigators recently to get the time to set an atomic wristwatch that was no longer getting signal from WWVB. When the Garmin was on, but before it received a GPS signal, I noticed the clock was off by a couple of minutes. That made be wonder how accurate Garmin navigators are at keeping time without a GPS signal.

Obviously, Garmin navigators need GPS signals to work properly and display time. However, is it possible that newer Garmin navigators keep track of time better if/when they don't have GPS signals?

I guess part of the reason I am wondering about this is in case I ever get a smartwatch, be it from Garmin, Samsung or another manufacturer. I realize that a smartwatch is designed to keep track of time and, hopefully, does a good job of that. How often do smartwatches need to get a GPS Signal to keep them on time? Or, do they use Bluetooth to a smartphone to sync time, as well?

Correct time

Jim1348 wrote:

I powered up one of my Garmin GPS navigators recently to get the time to set an atomic wristwatch that was no longer getting signal from WWVB. When the Garmin was on, but before it received a GPS signal, I noticed the clock was off by a couple of minutes. That made be wonder how accurate Garmin navigators are at keeping time without a GPS signal.

Obviously, Garmin navigators need GPS signals to work properly and display time. However, is it possible that newer Garmin navigators keep track of time better if/when they don't have GPS signals?

I guess part of the reason I am wondering about this is in case I ever get a smartwatch, be it from Garmin, Samsung or another manufacturer. I realize that a smartwatch is designed to keep track of time and, hopefully, does a good job of that. How often do smartwatches need to get a GPS Signal to keep them on time? Or, do they use Bluetooth to a smartphone to sync time, as well?

My wife has a Garmin Vivofit and she has had it for years. The only time I sync to the computer is during time change to daylight savings time. It has always kept good time.

--
Charlie. Nuvi 265 WT and Nuvi 2597 LMT. MapFactor - Offline Maps & GPS.

On GPS timing signals

Everything about the GPS is quite complex. For a good insight into the complexity, read the NASA article at https://ilrs.gsfc.nasa.gov/docs/timing/gpsrole.pdf.

Some of the content states "...and the timing accuracies can be in
the 100-nanosecond range."

--
John from PA

Maybe,

charlesd45 wrote:
Jim1348 wrote:

I powered up one of my Garmin GPS navigators recently to get the time to set an atomic wristwatch that was no longer getting signal from WWVB. When the Garmin was on, but before it received a GPS signal, I noticed the clock was off by a couple of minutes. That made be wonder how accurate Garmin navigators are at keeping time without a GPS signal.

Obviously, Garmin navigators need GPS signals to work properly and display time. However, is it possible that newer Garmin navigators keep track of time better if/when they don't have GPS signals?

I guess part of the reason I am wondering about this is in case I ever get a smartwatch, be it from Garmin, Samsung or another manufacturer. I realize that a smartwatch is designed to keep track of time and, hopefully, does a good job of that. How often do smartwatches need to get a GPS Signal to keep them on time? Or, do they use Bluetooth to a smartphone to sync time, as well?

My wife has a Garmin Vivofit and she has had it for years. The only time I sync to the computer is during time change to daylight savings time. It has always kept good time.

Does your wife use Garmin's Connect app on her phone? If she does then the Vivofit is getting the time from the phone whenever it automaticaly syncs.

--
I never get lost, but I do explore new territory every now and then.

Garmin Express

Use Garmin Express from the computer for vivofit.

--
Charlie. Nuvi 265 WT and Nuvi 2597 LMT. MapFactor - Offline Maps & GPS.

Its the crystal

While I lack specific detailed knowledge of GPSr design, I'm a little familiar with time-keeping (my first job out of college in 1974 was designing a watch chip for Intel).

As a broad generalization, whether you are talking about a PC, an "atomic watch" or almost anything else that has intermittent access to extremely accurate time, but somehow must generate a version of time between accesses, the key point is that they have a quartz crystal. How accurate they are is down to "the quartz lottery" on how close to perfectly on-frequency that specific sample of quartz crystal is, and how much it gets driven astray by environmental variables being off-optimal (mostly temperature and the operating voltage supplied to the oscillator).

If you win the quartz lottery, remarkably cheap devices can keep remarkably good time. I bought a daughter a cheap Timex watch decades ago which was off by far under a minute a year for some years. But if you bought 50 more of the same exact model, they would not have all done nearly so well.

Now if Garmin has spent more on battery crystals, or developed ways to run them that suffer less from temperature or voltage variation, a new model might do better. But if they found a way to save a few pennies, and assessed that the average user is unaffected, they could easily be worse.

--
personal GPS user since 1992

Garmin is making the

Garmin is making the interconnection of their device more complicated. They had a dash cam with turn-by-turn signal instructions. You can not link it with the Garmin GPS unit. It should you connected with the mobile phone. Nowadays, the interconnection between devices is so crucial. Apple does an excellent job in its device interconnection.

--
Sanjay Majumder

As someone has said, a

As someone has said, a quartz crystal is effected by temp (and voltage). If I recall, warm (hot) temps will cause will cause the time to slow and the opposite for cool (cold). A quartz is accurate but not 100%. My watch contacts WWV every night shortly after midnight (overkill). I compared it to GPS time at work and it's right on.