GPS issue in china

ttttttttt

i'm a local user in China (not a foreign traveler), so i don't have access to international roaming or foreign eSIMs that could bypass network restrictions. (i have a proxy service, but i won't enable all time.)
i found that battery drain quickly. i noticed it is gps issue.
running adb shell dumpsys location, I got this GNSS KPI data:

GNSS_KPI_START
KPI logging start time: +28s487ms
KPI logging end time: +5d8h8m18s991ms
Number of location reports: 930
Percentage location failure: 92.36559139784947
Number of TTFF reports: 7
TTFF mean (sec): 280.275
TTFF standard deviation (sec): 476.82394731239265
Number of position accuracy reports: 71
Position accuracy mean (m): 28.923541438411657
Position accuracy standard deviation (m): 42.25906592710122
Number of CN0 reports: 0
Total number of sv status messages processed: 4
Total number of L5 sv status messages processed: 0
Total number of sv status messages processed, where sv is used in fix: 0
Total number of L5 sv status messages processed, where sv is used in fix: 0
Number of L5 CN0 reports: 0
Used-in-fix constellation types:
GNSS_KPI_END

gps service always failed. i've enabled grapheneos proxy for SUPL and PSDS
it seems that it can not download satelite data?
and how can i know that satelite data download successfully

i am using grapheneos with build number 2026032001

Johnnyloans

ttttttttt TTFF mean (sec): 280.275
TTFF standard deviation (sec): 476.82394731239265

This is extremely poor performance. Your phone does support the Beidou network.

Try using a different option in:
settings > location
bottom 2 menus are SUPL & PSDS
(Maybe your phone fails to connect to one of them?)

Inside settings > location > location services
you could enable "network location"

Optionally turn on bluetooth or WiFi scanning (compare on and off?)

Also, it might depend on what maps app you use since China's GPS does things slightly different.

Being inside a building or radio signals being blocked by metal hurts accuracy/performance.

Take care mate.

ttttttttt

All kernel wake locks:
Kernel Wake lock gnss: 8m 53s 690ms (89 times) realtime
Kernel Wake lock gnss_ipc: 8m 27s 492ms (2549 times) realtime

dhhdjbd

Idk about gps,

but are you in a big city?
and / or use 5g?

because for me with pixel 8 it helped to turn off wifi (when not at home), and switch to 4g

ttttttttt

thanks for answer!
i am in shanghai, only use LTE (4G).
i enabled network location with provider Apple (China)
most apps' GPS permission is disabled.
most gps usage is for auto dark mode (turn on dark mode when sun rise)

i test with gps status & tools:
gps:

outdoor: get a fix fast
indoor: can not get a fix

fused location:

outdoor: failed
indoor: failed

(*) when i reset the AGPS data, it is successfully download, so it is probably not SUPL or PSDS download issue

when i open organic maps, it successfully locate indoor.
now, i disabled auto darkmode, using manual time from 18:00₆:00
i'll test today to see if the battery drain improves.
or simply disable gps, only enable when necessary (but i don't prefer that, maybe it is better privacy way?)

maade

@ttttttttt what device are you using?

ttttttttt

maade @ttttttttt what device are you using?

pixel 9a (i put it in the discussion tags)

it seems battery drain improved after i switched to manual dark mode schedule. (see above)
i'll continue testing