Accuracy of cell tower GPS

patienttruth99

Does Graphene OS report an accuracy to an app with network location fixes? There's an app "Traccar" that is showing "0m" for the occasional network location based fix. The developer said it a cell tower based fix shouldn't be reported as "0", so I'm wondering if it's something about GrapheneOS. We would like to filter out the less accurate fixes, but that won't work with 0 being reported.

Thanks for any info.

soupslurpr

patienttruth99 Yes, GrapheneOS reports an accuracy to an app that's requesting locations from the network-based location provider. Which specific parameter is being reported as 0m?

GrapheneOS

patienttruth99 Network location is primarily based on Wi-Fi, not cell towers. It only falls back to cell towers when it isn't able to obtain an estimate via Wi-Fi either because there aren't enough known networks or because it's disabled without Wi-Fi scanning enabled. We use the accuracy data from Apple's data for the networks and the resulting estimate should never have 0m as the accuracy.

patienttruth99

soupslurpr "accuracy” is showing "0" only for the fixes that are likely cell tower fixes since they are miles away. It happens occasionally throughout a day at home and will be the same approximate location. For the fixes that are in the actual general area of the phone I get reasonable numbers for accuracy like 1-5 meters.

The problem is that I can't filter out the lower accuracy cell fixes since they're logged as "0" currently. The author of the tracking software also does not expect "0" to ever be reported, even for wifi or cell fixes.

patienttruth99

GrapheneOS thanks for that. Any idea where 0 would come from?

soupslurpr

patienttruth99 interesting, for the other likely cell tower fixes at home, what are their accuracies?

patienttruth99

soupslurpr any of the other fixes I assumed were GPS fixes, and were <10m.

soupslurpr

@patienttruth99 Unfortunately, I don't think we can do much more about your issue without additional information. It may be Apple's server just having a 0 accuracy for one cell tower near you for some reason. You could check logs but it requires ADB to turn on the specific logs that tell you what info it gets from the server.

de0u

soupslurpr I wonder if the code could log anomalous results (such as zero), at least sometimes, without reconfiguration?

soupslurpr

de0u It can't as it would be a privacy issue.

de0u

soupslurpr Next dumb question: is there a small app, along the lines of GPSTest for GNSS, that could invoke the various location APIs in ways similar to what production apps would do, and display/log the results?

soupslurpr

de0u There is SatStat, but it has a low target SDK so it requires adb to install. I don't know of any other app that does this.