SOLVED: GPS working?

[espruino-discuss2]

Posted at 2020-03-26 by user110776

Hi. I got my Bangle.js today. Great device. All is well so far, except that I don't seem to be able to get a GPS lock. Using the GPS Info app from the Library, the watch never gets a fix, indoors or outdoors. Is that normal? Do I need to enable something extra?

Thanks, Gary.

[espruino-discuss2]

Posted at 2020-03-26 by Old_account

Not getting a proper fix indoors is normal. And from what's been posted previously I believe the first fix can take quite some time (I haven't received mine yet, still in the mail). How long did you wait?

[espruino-discuss2]

Posted at 2020-03-26 by user110776

Not getting a fix indoors isn't normal. But let's assume that due to antenna space etc that it won't get a fix indoors. As for outdoors, I would say I waited 2 maybe 3 minutes. I will try again tomorrow and wait longer.

[espruino-discuss2]

Posted at 2020-03-26 by user110776

OK, so reading about a bit on the ublox forums, maybe a cold TTFF could take up to 20 minutes. The question is this... What state does the watch need to be in to get the fix? If I just leave it outside for 20 minutes will it get a fix? Does a GPS specific app need to be running?

[espruino-discuss2]

Posted at 2020-03-26 by user110776

I left the watch outside for 30 minutes running the GPS Info app. The app keeps the watch on and it doesn't go to sleep. When I returned it had a fix. I don't know how long it took as I just left it there. So it looks like the cold TTFF is quite long.

As for indoors, it seems to be a bit hit and miss, which is probably expected. I think the fix jumps around a lot as the app is reporting my speed as > 2 km/h!!!

You can mark this is SOLVED/CLOSED/WHATEVER and maybe you could add this information to any FAQ you are working on.

Thanks.

[espruino-discuss2]

Posted at 2020-03-26 by nikmartin

Yes, the watches likely have never had a fix yet, or if they did it was in China or possibly the UK. Anytime you change locations over several 1000 miles you'll spend a good 10-15 minutes for a cold TTFF until the rx knows where ALL the satellites are.

[espruino-discuss2]

Posted at 2020-03-26 by Paul

finding the satellites should be a lot quicker the next time you restart it.

Inside, it will pick up fewer satellites, if any, because the radio signal is very weak, so it will get blocked easily. That will reduce its accuracy considerably.

[gfwilliams]

Posted at 2020-03-27 by @gfwilliams

Glad you got it sorted.

Not getting a fix indoors isn't normal.

Phones and internet-connected GPS devices use AGPS (A=Assisted). They use the time and rough location info from mobile phone masts to help them get a fix much faster. Since Bangle.js doesn't have that info it's working from first principles and it can take a while to get a lock - I'd say usually 5 mins does it, but leave up to 10.

After that initial lock, it'll be much faster to get a lock again, even indoors.

[espruino-discuss2]

Posted at 2020-07-06 by DrBard

I might be a bit late to this but surely the bangle.js could use the current time (if it is told this is accurate)?

[gfwilliams]

Posted at 2020-07-07 by @gfwilliams

That could help, but it still doesn't even know which country it's in.

It has been suggested that we could have an app that loads AGPS data into the GPS receiver, and that actually looks pretty promising - you can add data for a few weeks in advance, and when you do that the fix should be faster/better.