[android] Google Play Location API returns bogus location in the first 1-2 seconds #2149

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opened 2022-02-19 12:32:31 +00:00 by rtsisyk · 0 comments

rtsisyk commented

2022-02-19 12:32:31 +00:00

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A test case:

Open the app
Wait until precise location is acquired from hardware GPS.
Ensure that no other apps are using location.
Lock the screen.
Unlock the screen.
Open the app.
The app will show a previous location for 1-2 seconds, then jump to a location far away for 1-5 seconds, and then start jump back to the proper location.

Explanation:

The app disables all location services when going into the background, i.e. then the user switches to another app or locks the screen.
Android disables hardware GPS almost immediately if there are no active apps using it.
On the next run, the app starts location services again.
Google Play Location API returns network location instantly. This location can be 10-700 meters away from the real location. The accuracy depends on situation. In cities, the accuracy of the first location is about ~10 meters. In a forest, it can be up to 700 meters inaccurate.
The app blindly trusts all results returned from Google Play Location API.
HW GPS catches up and starts returning proper location 1-2 seconds.

This issue reproduces both on the new (#2023 #2087) and previous implementation.

Below is logcat after resuming the app:

2022-02-13 13:28:12.796 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.852561,37.312428 hAcc=699.999 et=+2d2h41m23s327ms alt=192.40202601485817 vAcc
=14.377255 {Bundle[EMPTY_PARCEL]}]
2022-02-13 13:28:15.722 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.846022,37.311573 hAcc=48.0 et=+2d2h41m27s412ms alt=192.40202601485817 vAcc=13
.479849 vel=0.37648338 sAcc=0.6590801 bear=68.0 bAcc=180.0 {Bundle[EMPTY_PARCEL]}]
2022-02-13 13:28:18.683 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.846000,37.311548 hAcc=49.736 et=+2d2h41m30s417ms alt=192.4040892666825 vAcc=1
3.44495 vel=0.09437784 sAcc=0.67334217 bear=87.855286 bAcc=180.0 {Bundle[EMPTY_PARCEL]}]
2022-02-13 13:28:20.678 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.845981,37.311509 hAcc=39.525 et=+2d2h41m32s409ms alt=192.4040892666825 vAcc=1
3.43119 vel=0.22056967 sAcc=0.21031955 bear=138.34778 {Bundle[EMPTY_PARCEL]}]
2022-02-13 13:28:22.099 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.845975,37.311519 hAcc=29.39 et=+2d2h41m33s832ms alt=192.34425516820477 vAcc=1
3.362372 vel=0.42359042 sAcc=0.20136186 bear=138.66772 {Bundle[EMPTY_PARCEL]}]

Please note, the first location has provider="fused" and location hAcc=699.999 of the first returned result.

See also #2034

A test case: 1. Open the app 2. Wait until precise location is acquired from **hardware** GPS. 2. Ensure that no other apps are using location. 3. Lock the screen. 4. Unlock the screen. 5. Open the app. 6. The app will show a previous location for 1-2 seconds, then jump to a location **far away** for 1-5 seconds, and then start jump back to the proper location. Explanation: 1. The app disables all location services when going into the background, i.e. then the user switches to another app or locks the screen. 2. Android disables hardware GPS almost immediately if there are no active apps using it. 3. On the next run, the app starts location services again. 4. Google Play Location API returns network location instantly. This location can be **10-700 meters** away from the real location. The accuracy depends on situation. In cities, the accuracy of the first location is about ~10 meters. In a forest, it can be up to 700 meters inaccurate. 5. [**The app blindly trusts all results returned from Google Play Location API.**](https://github.com/organicmaps/organicmaps/blob/d02453b52f760459c41dc4dd825cacdb744a8e5f/android/src/com/mapswithme/util/LocationUtils.java#L89-L92) 6. HW GPS catches up and starts returning proper location 1-2 seconds. This issue reproduces both on the new (#2023 #2087) and previous implementation. Below is logcat after resuming the app: ``` 2022-02-13 13:28:12.796 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.852561,37.312428 hAcc=699.999 et=+2d2h41m23s327ms alt=192.40202601485817 vAcc =14.377255 {Bundle[EMPTY_PARCEL]}] 2022-02-13 13:28:15.722 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.846022,37.311573 hAcc=48.0 et=+2d2h41m27s412ms alt=192.40202601485817 vAcc=13 .479849 vel=0.37648338 sAcc=0.6590801 bear=68.0 bAcc=180.0 {Bundle[EMPTY_PARCEL]}] 2022-02-13 13:28:18.683 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.846000,37.311548 hAcc=49.736 et=+2d2h41m30s417ms alt=192.4040892666825 vAcc=1 3.44495 vel=0.09437784 sAcc=0.67334217 bear=87.855286 bAcc=180.0 {Bundle[EMPTY_PARCEL]}] 2022-02-13 13:28:20.678 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.845981,37.311509 hAcc=39.525 et=+2d2h41m32s409ms alt=192.4040892666825 vAcc=1 3.43119 vel=0.22056967 sAcc=0.21031955 bear=138.34778 {Bundle[EMPTY_PARCEL]}] 2022-02-13 13:28:22.099 main: D/LocationHelper: onLocationChanged, location = Location[fused 55.845975,37.311519 hAcc=29.39 et=+2d2h41m33s832ms alt=192.34425516820477 vAcc=1 3.362372 vel=0.42359042 sAcc=0.20136186 bear=138.66772 {Bundle[EMPTY_PARCEL]}] ``` Please note, the first location has `provider="fused"` and location `hAcc=699.999` of the first returned result. See also #2034

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