Just updated my Fenix 5X with a new GPS Update. Not sure what improvements this is intended to provide but it is available on Garmin Express, though does not show as a software download otherwise on Garmin's support page as of tonight.
From past experience with GPS chip software updates on the Fenix series, the update wipes all previous satellite data stored on the watch; this is more than that which is contained in the EPO.bin files transferred to the watch on sync with Garmin Express or Garmin Connect Mobile. On the occasions when the Garmin folks have added instructions with GPS updates (as was the case a couple of months after the Fenix 3 came out), after the update is installed, we were advised to first record a GPS activity, remaining static with a clear view of the sky, for 20-25 minutes. That activity can be discarded rather than saved at the end. The point of this was to gather the initial satellite data (I forget the correct technical term for that data), which is on a transmission cycle of approx 10-15 minutes and is not contained within an epo.bin file. It is this extra data that makes future initial GPS fixes quicker and also makes general GPS accuracy better. There is more general advice around on the internet to do this same GPS "static soak" if you travel a long distance (several hundred miles) from where you last used a handheld GPS device, or you've had the device switched off or not used GPS for a long time.
From past experience with GPS chip software updates on the Fenix series, the update wipes all previous satellite data stored on the watch; this is more than that which is contained in the EPO.bin files transferred to the watch on sync with Garmin Express or Garmin Connect Mobile. On the occasions when the Garmin folks have added instructions with GPS updates (as was the case a couple of months after the Fenix 3 came out), after the update is installed, we were advised to first record a GPS activity, remaining static with a clear view of the sky, for 20-25 minutes. That activity can be discarded rather than saved at the end. The point of this was to gather the initial satellite data (I forget the correct technical term for that data), which is on a transmission cycle of approx 10-15 minutes and is not contained within an epo.bin file. It is this extra data that makes future initial GPS fixes quicker and also makes general GPS accuracy better. There is more general advice around on the internet to do this same GPS "static soak" if you travel a long distance (several hundred miles) from where you last used a handheld GPS device, or you've had the device switched off or not used GPS for a long time.
Does this mean that the second time i track my run with gps the route must be much better?
Crispin, I guess you were searching for the terms GPS almanac and ephemeris data. As a simplification almanac and ephemeris data are needed for positioning and a fast fix, respectively.
The "stored data" mostly controls the speed of the first fix; if the GPS knows where the satellites "should" be then it can acquire a lock more-quickly. Once it has a lock on the first satellite then it can pretty-rapidly get the others that it has in view since once the data stream starts coming in from the first one it knows where the others in the constellation are. Ultimately the quality of the track (e.g. accuracy) is limited by whether SA is on (hasn't been for many years, but could be turned back on at some point in the future), how many satellites are in-view, whether WAAS corrections are being received and processed, and the impact of both multipath and S/N on the received signal quality, which is both a function of the environment (e.g. tall buildings around, etc) and the antenna of the receiver.
I guess you were searching for the terms GPS almanac and ephemeris data
Yup, they’re the ones thanks :)
Does this mean that the second time i track my run with gps the route must be much better?
tickerguy has covered the multitude of complex variables that impact track accuracy. So there’s absolutely no certainty that a second track will be better, but it might explain a particularly bad track during the first run after the update.
Crispin - I noticed my first GPS fix yesterday after the update took over 10 minutes (didn't time it exactly, but about consistent with the time it takes to download almanac data - 12.5 minutes).
The GPs update appears to be unlisted but a by product of downloading the maps from GC. Once the download was complete and the watch disconnected the watch the asked to update GPS.
Not in my case. I have had the new maps listed for a while now (not in a rush to update). There was no sign of the GPS update (on my GE) until yesterday where it showed up as an additional update available (along with the maps). Installed it by itself without a problem. Restarted the watch and ran an activity as I was driving to training (although it did not actually take long to get the initial lock). As the release notes are really vague, I have no idea what, if any, improvements could be expected.
