Location Services for Emergency Calls

SignalScout

I work updating and correcting map data for a rural county in the United States. I was working with some state experts upgrading some pretty horrendous errors from the old landline telephone days when they asked if I had performed any 911 test calls from that area. I'm pretty reluctant to use my Pixel 9a Graphene phone to do this, and I have considered asking to borrow a county phone.

The last time I tried this was with an e/os phone and I recall it turned a bunch of privacy features off and was never really confident that I had successfully reenabled them.

Are my concerns unfounded? Thanks!

DeletedUser370

SignalScout The last time I tried this was with an e/os phone and I recall it turned a bunch of privacy features off and was never really confident that I had successfully reenabled them.

A web search will reveal that Android contains code to automatically disable airplane mode and enable microphone access when a user calls an emergency number.

Google's stock OS contains a feature called AML (Advanced Mobile Location) which is programmed to collect GNSS and WiFi location data when a user calls an emergency number and to send the coordinates to the PSAP that receives the emergency call. AML requires privileged Google Play and it is not included in GrapheneOS. This is also openly documented on the internet.

I agree with de0u that the question needs to be clarified.

SignalScout

SignalScout One of the draws of Graphene for a lot of users is that you don't necessarily have to know all of the features and differences between OS to install it and use it.

I'll just borrow a work phone. Thanks.

GrapheneOS

SignalScout

The last time I tried this was with an e/os phone and I recall it turned a bunch of privacy features off and was never really confident that I had successfully reenabled them.

This is not something that's present in the Android Open Source Project, stock Pixel OS or GrapheneOS. Making an emergency call only enables the minimal functionality required to make an emergency call and provide a location estimate. It's trivial to turn that off afterwards. It doesn't make any non-trivial or non-obvious settings changes. It will not give apps access to location and microphone data unless you already granted them persistent access via the permissions. You should already be using the permission system to grant one-time access if you don't want to grant persistent access rather than relying on having the global toggles for Location and Microphone disabled. The global toggles can be useful but it's better to use the permission system.

Open_Source_Enjoyer

SignalScout The last time I tried this was with an e/os phone and I recall it turned a bunch of privacy features off and was never really confident that I had successfully reenabled them.

What privacy features did it turn off?
If its turn on your microphone, then its a feature not a bug.
And to change it back after is eassier then borrow a phone.

SignalScout

Nobody?

de0u

SignalScout Nobody?

I have previously placed 911 calls from a 3a and a 6a both running GrapheneOS without observing anything concerning, and would do it again.

I think maybe there aren't a lot of people jumping in to answer because perhaps people here haven't run that other OS and also because the original post didn't contain specifics, just said "a bunch of privacy features". Perhaps a question with details might elicit more responses.

soupslurpr

SignalScout you didn't clarify your question, it's unclear what you're asking. Can you please clarify? Emergency calls work fine on GrapheneOS, including E911. Though the network location settings aren't currently overridden so location might not be reported or have lower accuracy if that's off and there is no GNSS lock.

GrapheneOS

SignalScout

I'll just borrow a work phone. Thanks.

This is really not necessary and doesn't make sense.

SignalScout

What I want to know, is if dialing 911 enables any location service or tracking on the device that I then have to go back and manually disable?

This stems from trying to do this task on an e/os phone. When I dialed, the phone popped up a message that that had changed something. I don't recall what. It was a year ago.

GrapheneOS

SignalScout

What I want to know, is if dialing 911 enables any location service or tracking on the device that I then have to go back and manually disable?

It does not enable any location tracking and doesn't change settings like SUPL, PSDS or network location. We could add the option of automatically enabling those 3 things for emergency calls, at least temporarily, but it doesn't exist right now.

It's easy enough to turn the prominent global toggles back off afterwards. There are no non-trivial or non-obvious things changed by it.

juanolo

https://docdb.cept.org/download/3552

4.2 HANDSET-BASED LOCATION INFORMATION (ADVANCED MOBILE LOCATION)

Modern mobile devices with Global Navigation Satellite System (GNSS) capabilities can calculate a very
accurate location. In Europe, a technology called Advanced Mobile Location (AML) has been widely deployed. In the event of an emergency call, an AML-enabled device (all Android and iOS devices worldwide support AML) will automatically calculate its position and send this location information to the emergency services. The device also has the capability to augment GNSS location information with Cell-ID and location information obtained from nearby Wi-Fi devices to further verify the accuracy and reliability of the location information received. It should be noted that even though almost all smartphones in the world support AML, the infrastructure for supporting it may not yet be available in all countries. AML is currently deployed in 23 CEPT countries (Austria, Belgium, Croatia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Latvia, Lithuania, Malta [16], Moldova, The Netherlands, Norway, Romania, Slovenia, Sweden, United Kingdom) as well as in New Zealand, United Arab Emirates and the US [11].

4.3 CALLER LOCATION THROUGH IMEI

In such cases where the CLI cannot be determined and transmitted to the PSAP by the originating network, the originating network should provide alternative information to the PSAP [13]. In this situation, an identifier of the device (i.e. IMEI) or the SIM in the case of a device with a valid SIM in LSS for another reason (i.e. IMSI), may be transmitted by the originating network. When only the IMEI is received, the PSAP call taker can deduce that the call is from a device in LSS and possibly does not have a valid SIM.

Signed by Nusko