Bangle 2 GPS - time for first fix, quite variable

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  • Yes, Bangle.js 1 does have better GPS reception (however it seems using AGPS and setting it to just use GPS you can improve Bangle.js 2).

    Unfortunately I think it's just a side-effect of the maybe not so good GPS chip (AT6558 vs Ublox) and the much more constrained size for the aerial.

  • Thanks for the tips! Indeed, after installing the AGPS app, my Bangle2 now usually acquires a GPS lock in about 10-20 seconds. It seems that the AGPS data is lost after shutting down the watch, however.

  • It seems that the AGPS data is lost after shutting down the watch, however.

    It shouldn't be... It'll be lost when the watch runs out of power, but not due to powering the watch off via the menu

  • Interesting--perhaps the AGPS data "expired" while my watch was turned off then? I noticed that the AGPS app for Bangle.js 1 gives the user the option to select how much data to download but that option isn't provided for Bangle.js 2. I think it had been a couple of days since I last uploaded AGPS data so perhaps only a couple days' worth of data is uploaded to Bangle.js 2.
    Regardless, using the AGPS app on days when I need to use GPS is easy so it's a non-issue. Thanks!

  • I think it had been a couple of days since I last uploaded AGPS data so perhaps only a couple days' worth of data is uploaded to Bangle.js 2.

    Yes... On Bangle.js 2 we only get enough data to last for ~48 hours I think, so that's probably it

  • Can't you "just" implement frequent AGPS data uploading (like once a day) to Gadgetbridge as an option?

  • Github user pidajo is developing an app for pulling the AGPS data directly from the bangle over the Gadgetbridge http functionality: https://github.com/espruino/BangleApps/p­ull/1974

  • I think that app is merged now too.

    Can't you "just" implement frequent AGPS data uploading (like once a day) to Gadgetbridge

    I could, if I had any time at all :) Others are welcome to contribute code though!

    In an ideal world, we'd have a way to have JS running on the phone push data to the Bangle, but I think in the absence of that, the app mentioned above is really the way to go.

  • I am having an issue with GPS. I didn't use it much when the Bangle first arrived. I tested it and got a (slow) lock outside, but because I couldn't run for months after having covid that was about it. I recently started running again and I had a couple of weeks getting a really fast lock as long as I uploaded agps immediately before going, but the last few times I have uploaded the data but still no lock before giving up. This morning I fired gpsinfo up to see what was happening and it showed GP/BD/GL 10 2 0, but no lock. I only selected GPS onthe AGPS config and its the first time it I have noticed more than 1 for BD, but guess that is a red herring. Any thoughts?

  • That's an odd one - not sure... But the fact it's reporting 10 satellites for GPS implies that you should have a good lock. I think as long as you have 4 or more, GPS usually starts giving you location information.

    So maybe it's actually a software issue?

  • Did anything change around GPS in the latest firmware? Before I saw how many satellites it was seeing I thought maybe the AGPS data was off somehow. Now I am wondering whether it is "seeing" satellites that aren't there. All wild speculation.

  • Did anything change around GPS in the latest firmware?

    Not that I'm aware of, no... I guess you could try using some code like Bangle.on('GPS',print);Bangle.setGPSPowe­r(1) to see if the raw data coming from Bangle.js is ok

  • I missed your last message Gordon, I will try that next time. In case anyone else has the same issue: I've had it happen a few times and running the battery down to completely power the watch off is what solves it for a while. I can't see a pattern about when it happens.

  • I've had it happen a few times and running the battery down to completely power the watch off is what solves it for a while

    I see something similar on my B2: I can only get a GNSS fix after rebooting the watch.
    Until i do that it tries to get a fix for several minutes - without success. After reboot the fix is there in a less than a minute usually - if i am outside.

  • Hi everyone! Experiencing the same issue here.
    I upload the AGPS data but still it takes at least 7/10 minutes to get the first fix. Anyone experiencing the same issue despite the upload?
    @myxor did you notice a pattern?
    F

  • How do you upload AGPS data? Was it with https://banglejs.com/apps/?id=assistedgp­s or something else ? And how long before using the Bangle did you update the data?

    There have been issues with the other app/widget there not always being able to update, so that could be an issue.

  • @Gordon I upload exactly using the "assistedgps" app. My procedure is as follows:

    • Upload the AGPS data
    • Start my monitoring program (which simply enables GPS and prints location)

    Despite that it takes a lot to get the first fix (I selected to upload all constellations).
    Btw, is there a way to upload the the AGPS data programmatically using the assistedgps code?
    Thanks

  • I selected to upload all constellations

    Is this for Bangle.js 2? If so you may be having the opposite effect to what you intend. For instance by enabling just GPS you're actually freeing up more computation in the GPS receiver so you can get a fix more quickly.

    is there a way to upload the the AGPS data programmatically using the assistedgps code?

    You need to get it from the internet - but if you check out the AGPS app, it can do that via Gadgetbridge

  • @Gordon yes it's for Bangle.js 2. I'm trying every day with different configurations and this morning I've tried uploading GPS data only and I still got 17-19 mins for the first fix.

    • Do you have any suggestions? I'm in Italy if it can help. BTW
    • Is there a way to erase the AGPS data to perform cold start tests more quickly without waiting a day or so?
  • Hi, How are you waiting for the fix to occur? Do you leave the Bangle somewhere outside where it can see GPS satellites, or are you inside, in a city, or wearing it while walking around?

    It can be pretty hard to get a satellite fix when it's being moved around a lot because the satellites it is searching for come and go.

    Is there a way to erase the AGPS data to perform cold start tests more quickly without waiting a day or so?

    There may be a way to delete the AGPS data but I don't know it. I'd maybe run the battery down until the device turns off which will 100% reset the GPS, then you could just partially charge it to do some tests, then discharge it (there is an option in Settings->Utils to quickly discharge).

    In terms of improving time to lock, it may be possible to upload the estimated GPS location and time. I would love to do this and there are some threads about it, but the GPS chip is pretty badly documented so it's hard to know exactly what data needs to be sent.

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Bangle 2 GPS - time for first fix, quite variable

Posted by Avatar for HughB @HughB

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