Time sync off by 7 seconds

you are welcome !

I just now found this thread and remembered that when I first got my Fenix 6 last summer I noticed the same thing when doing a GPS sync.

I'm not sure I ever figured it out completely, but one thing I noticed is if I purposely set the watch time off by a few minutes and did the GPS manual sync, then it synched to the proper time. 

I also seem to recall if it was off by just a few seconds, the GPS sync would report the correct time when manually synching, but then 15-30 seconds later the watch would be back to the incorrect time again, as if it never accepted the sync.

Haven't experimented with it since then, and only tried a few times when I did experiment, but I'm curious to hear if anyone else has tried the method of setting the time way off and see if it helped sync to the exact second.

Hi,

I have not experimented that much. As I wrote, after the manual GPS sync the precision becomes within +/- 1 second tolerance, which is good for me. Because, as I have read somewhere, we cannot expect cell phones or smart watches be as precise as radio-controlled watches. For example, I have verified two cell phones run by different network operators just right now and there is an obvious 1 second difference.

The only thing I expected was a periodical automatic GPS time sync, however, this function is not available, as Allalin72 explained. But well, pressing one button for manual GPS time sync is not a big deal.

My guess is, that the reason why Garmin does not tackle this issue is that most of users engage their watches in an activity mode frequently and in this way their watches always show more or less close to precise time.

Speaking about experiments, my initial concern was that having synced by GPS manually, the precision might be ruined by the next automatic sync with the paired phone. Fortunately, it is not the case. It seems, that by syncing with a paired phone only minutes are adjusted and seconds are left on their own.

The other experiment I have not done so far, because I need a month or a month and a half for that. The idea is the following. If not synced with GPS, the watch becomes 1-2 seconds late on daily basis. I am curious what happens the next day once the watch is already 59 seconds late? Will paired phone keep it 59 seconds late adjusting only a minute precision, or it would break the minute precision barrier? But well, I need to keep it out of the GPC sync for one months or more, certain determination is needed for this type of experiment.

Hi Allalin72!

From your previous explanations I understood that a GPS receiver in a watch stays disconnected, unless:

1) manually activated for the time sync;

2) an activity is activated using GPS for tracking the route of a user.

I would really much appreciate if you could confirm/deny if my understanding is correct about the following.

I found at least two sections in the watch where I can select between modes of GPS seeking balance between the battery life and precision of tracking.

1) Activities & Apps – a specific activity (cardio e.g.) – GPS:

1. Off
2. GPS only
3. GPS + GLONASS
4. GPS + GALILEO
5. UltraTrac

2) Power Modes:

1. Don’t Change
2. Turn Off
3. Normal
4. Ultra Trac
5. GPS + GLONASS
6. GPS + GALILEO

Question 1. Is it correct, that no matter which mode of GPS I select, it does not affect the battery life anyhow until I switch on an activity?

Question 2. If my above assumption is correct, which means that the GPS receiver is off if the watch is not in an activity mode, how the watch counts steps and estimates walked distance then? It can take GPS data from a paired phone of course. However, even if I walk all day long with the phone unpaired, steps are still recorded on the watch and then in the evening, once paired with the phone, the steps are displayed in the “Connect” app. Again, may guess is, that the watch estimates steps based on the movement of hand and it estimates walked distance accordingly. This is why there is an option to “Custom Stride Lengths” which enables the phone to estimate more accurate walked distance based on the counted steps. Am I right?

Thank you very much in advance!

5405423 said:

as I have read somewhere, we cannot expect cell phones or smart watches be as precise as radio-controlled watches.

My Iphone XR is constantly in sync with my radio controlled clock without any deviation. Apple gets the time over the internet. I have not yet been able to determine any deviation between the iPhone time and the radio clock. However, when synchronizing via GCM, I was able to determine up to 10 seconds deviation from the iPhone.

Thank you for clarification. It is interesting to know that iPhone gives a precise time. I found 1 second difference between Samsung and ZTE.

5405423 said:

may guess is, that the watch estimates steps based on the movement of hand and it estimates walked distance accordingly. This is why there is an option to “Custom Stride Lengths” which enables the phone to estimate more accurate walked distance based on the counted steps. Am I right?

right !

5405423 said:

Question 1. Is it correct, that no matter which mode of GPS I select, it does not affect the battery life anyhow until I switch on an activity?

It should be like that. If I read correctly, there are reports that the watch occasionally remains in GPS mode. But that shouldn't be the case. This would be incorrect behavior, which leads to increased battery consumption. You can find more about this in the "Increased Battery Usage" threads.

Many thanks again!

Thank you!