Android Question Get coordinates from GPS

[Sergey_New]

Please tell me if it is possible to get coordinates of the current position using the GPS library. No map required, only coordinates.

 

[TILogistic]

Yes,

GPS / GNSS tutorial

The GNSS library replaces the old GPS library. The GNSS library is available here: https://www.b4x.com/android/forum/threads/gnss-library-an-updated-gps-library.109110/#content Using it is quite simple: 1. Checking whether location services are available. If not take the user to the...

www.b4x.com

 

[emexes]

Most GPS chips also measure speed directly, via Doppler shift, which is more accurate than taking two positions and dividing distance between them by time.

Which reminds me:

Charles Doppler had five children; what were they called?

Dopplegangers.

What do you call a guy who's been hit in the head with a shovel?

Doug.

What do you call a guy with 50 rabbits up his bum?

Warren.

 

[Sergey_New]

Yes,

Thank you!
The time to receive coordinates with the GNSS library is more than 10 seconds.
When using the GoogleMap library, this time is about 1 second.
Is there anything that can be done to reduce the time?

 

[Serge Bertet]

Make sure you are testing outdoor, you could get better results.

 

[Sergey_New]

Make sure you are testing outdoor, you could get better results.

Both tests were carried out under identical conditions, practically in the open air.

 

[Cableguy]

keep in mind that, as developers, we can only use "open" satellite constellations, slower, less accurate (typically <1m, while Digital Giants, like google, have access to faster and more accurate Satellites, with accuracies of less than 10cm at times.
What you can do, is use the GoogleMap lib without showing the actual map, and just extracting the info you need.

 

[Sergey_New]

Cableguy, that's what I do. But unfortunately, even though the GoogleMap key is free, it's tied to my debit card, which is about to expire. It's not possible to extend it in my country.

 

[Cableguy]

Cableguy, that's what I do. But unfortunately, even though the GoogleMap key is free, it's tied to my debit card, which is about to expire. It's not possible to extend it in my country.

yeap, that's google!

 

[Sergey_New]

yeap, that's google!

 

[emexes]

under identical conditions

Simultaneously?

Or was one test done before the other?

The Google location is probably fused, eg starts off by using cell tower location, then to a wi-fi/Bluetooth estimate based on "visible" nearby devices of known position, and then finally to GPS after a time-to-first-fix period when it works out what satellites are visible and their precise orbital position, and aligns (correlates, synchronises) the ranging codes.

 

[Sergey_New]

Simultaneously?

Consistently, immediately one after the other. Changed their sequence, the results are the same.

 

[Cableguy]

Consistently, immediately one after the other. Changed their sequence, the results are the same.

also keep in mind that google services are (may be) running in the background, so sat lock and other geo stuff are already available from those services to GMaps!

 

[emexes]

Changed their sequence, the results are the same.

That is intriguing. Perhaps even a little worrying. 🫣

What if you move 50 metres between the tests. Does Google Map library immediately return the new location when you start it, or is it returning the last known location until the GPS chip "catches up"?

 

[Sergey_New]

What if you move 50 metres between the tests.

I'll check and let you know. But I need a one-time and not very precise receipt of coordinates. Not required while moving.

 

[emexes]

When using the GoogleMap library, this time is about 1 second.

I'm going to guess that it's something to do with this:

Cached Location Data: The library often retrieves the last known location from the device’s location cache, which is stored by the Android LocationManager or iOS Core Location. This cached data provides an immediate rough estimate of the location, reducing the wait time for a fresh GPS fix.

sounds right, but not yet verified outside of AI, which has sometimes been known to just make sh*t up

https://x.com/i/grok/share/ecKxBEUF5fiENriGfemBhxL5s

 

[emexes]

But I need a one-time and not very precise receipt of coordinates.

My ex-wife is currently flying Australia to India. When she gets off the plane in Delhi, I would expect that for a few seconds to tens-of-seconds, her phone will be thousands of kilometres not very precise. Would your app be ok with that?

From a pragmatic perspective: if Google Maps library is providing the info you need, faster than a GNSS library that is only returning you real actual position fixes, and not interim best guesses or stale old positions, then can you just use that?

edit: still interested in your confirmation of whether or not Google Maps library is caching position and feeding you that when it starts up

 

[Sergey_New]

then can you just use that?

I guess I'll have to do just that. It's a shame to give up a better solution.

 

[emexes]

It's a shame to give up a better solution.

Perhaps use them both?

The Google Maps library to get a quick probably-correct location.

But confirmed ten seconds later by an actual GPS location fix.

Trust, but verify - Wikipedia

en.wikipedia.org

 

[Sergey_New]

Perhaps use them both?

It's not possible to extend it in my country.